document_title: Coriolis force

question_text: what is the term for circular movement around a central point

question_tokens: what is the term for circular movement around a central point

text: Coriolis force

text: History[edit]

text: Italian scientist Giovanni Battista Riccioli and his assistant Francesco Maria Grimaldi described the effect in connection with artillery in the 1651 Almagestum Novum, writing that rotation of the Earth should cause a cannonball fired to the north to deflect to the east.[7] In 1674 Claude François Milliet Dechales described in his Cursus seu Mundus Mathematicus how the rotation of the Earth should cause a deflection in the trajectories of both falling bodies and projectiles aimed toward one of the planet's poles. Riccioli, Grimaldi, and Dechales all described the effect as part of an argument against the heliocentric system of Copernicus. In other words, they argued that the Earth's rotation should create the effect, and so failure to detect the effect was evidence for an immobile Earth.[8] The Coriolis acceleration equation was derived by Euler in 1749[9][10] and the effect was described in the tidal equations of Pierre-Simon Laplace in 1778.[11]

text: Gaspard-Gustave Coriolis published a paper in 1835 on the energy yield of machines with rotating parts, such as waterwheels.[12] That paper considered the supplementary forces that are detected in a rotating frame of reference. Coriolis divided these supplementary forces into two categories. The second category contained a force that arises from the cross product of the angular velocity of a coordinate system and the projection of a particle's velocity into a plane perpendicular to the system's axis of rotation. Coriolis referred to this force as the "compound centrifugal force" due to its analogies with the centrifugal force already considered in category one.[13][14] The effect was known in the early 20th century as the "acceleration of Coriolis",[15] and by 1920 as "Coriolis force".[16]

text: In 1856, William Ferrel proposed the existence of a circulation cell in the mid-latitudes with air being deflected by the Coriolis force to create the prevailing westerly winds.[17]

text: The understanding of the kinematics of how exactly the rotation of the Earth affects airflow was partial at first.[18] Late in the 19th century, the full extent of the large scale interaction of pressure-gradient force and deflecting force that in the end causes air masses to move along isobars was understood.[citation needed]

text: Formula[edit]

text: In non-vector terms: at a given rate of rotation of the observer, the magnitude of the Coriolis acceleration of the object is proportional to the velocity of the object and also to the sine of the angle between the direction of movement of the object and the axis of rotation.

text: The vector formula for the magnitude and direction of the Coriolis acceleration is derived through vector analysis and is[19]

text:
where (here and below)

a

C

{\displaystyle {\boldsymbol {a}}_{C}}

 is the acceleration of the particle in the rotating system,

v

{\displaystyle {\boldsymbol {v}}\,}

 is the velocity of the particle with respect to the rotating system, and Ω is the angular velocity vector having magnitude equal to the rotation rate ω, with direction along the axis of rotation of the rotating reference frame, and the

×

{\displaystyle {\boldsymbol {\times }}}

 symbol represents the cross product operator.

text: The equation may be multiplied by the mass of the relevant object to produce the Coriolis force:

text: See fictitious force for a derivation.

text: The Coriolis effect is the behavior added by the Coriolis acceleration. The formula implies that the Coriolis acceleration is perpendicular both to the direction of the velocity of the moving mass and to the frame's rotation axis. So in particular:

text:
if the velocity is parallel to the rotation axis, the Coriolis acceleration is zero. (For example, on Earth, this situation occurs for a body on the equator moving north or south relative to Earth's surface.)
if the velocity is straight inward to the axis, the acceleration is in the direction of local rotation. (For example, on Earth, this situation occurs for a body on the equator falling downward, as in the Dechales illustration above, where the falling ball travels further to the east than does the tower.)
if the velocity is straight outward from the axis, the acceleration is against the direction of local rotation. (In the tower example, a ball launched upward would move toward the west.)
if the velocity is in the direction of local rotation, the acceleration is outward from the axis. (For example, on Earth, this situation occurs for a body on the equator moving east relative to Earth's surface. It would move upward as seen by an observer on the surface. This effect (see Eötvös effect below) was discussed by Galileo Galilei in 1632 and by Riccioli in 1651.[20])
if the velocity is against the direction of local rotation, the acceleration is inward to the axis. (On Earth, this situation occurs for a body on the equator moving west, which would deflect downward as seen by an observer.)

tag: ul

text: Causes[edit]

text: The Coriolis force exists only when one uses a rotating reference frame. In the rotating frame it behaves exactly like a real force (that is to say, it causes acceleration and has real effects). However, the Coriolis force is a consequence of inertia,[21] and is not attributable to an identifiable originating body, as is the case for electromagnetic or nuclear forces, for example. From an analytical viewpoint, to use Newton's second law in a rotating system, the Coriolis force is mathematically necessary, but it disappears in a non-accelerating, inertial frame of reference. For example, consider two children on opposite sides of a spinning roundabout (Merry-go-round ), who are throwing a ball to each other. From the children's point of view, this ball's path is curved sideways by the Coriolis force. Suppose the roundabout spins anticlockwise when viewed from above. From the thrower's perspective, the deflection is to the right.[22] From the non-thrower's perspective, deflection is to the left. For a mathematical formulation see Mathematical derivation of fictitious forces. In meteorology, a rotating frame (the Earth) with its Coriolis force provides a more natural framework for explanation of air movements than a non-rotating, inertial frame without Coriolis forces.[23] In long-range gunnery, sight corrections for the Earth's rotation are based upon the Coriolis force.[24] These examples are described in more detail below.

text:
The acceleration entering the Coriolis force arises from two sources of change in velocity that result from rotation: the first is the change of the velocity of an object in time. The same velocity (in an inertial frame of reference where the normal laws of physics apply) is seen as different velocities at different times in a rotating frame of reference. The apparent acceleration is proportional to the angular velocity of the reference frame (the rate at which the coordinate axes change direction), and to the component of velocity of the object in a plane perpendicular to the axis of rotation. This gives a term

−

Ω

×

v

{\displaystyle -{\boldsymbol {\Omega }}\times {\boldsymbol {v}}}

. The minus sign arises from the traditional definition of the cross product (right-hand rule), and from the sign convention for angular velocity vectors.

text:
The second is the change of velocity in space. Different positions in a rotating frame of reference have different velocities (as seen from an inertial frame of reference). For an object to move in a straight line, it must accelerate so that its velocity changes from point to point by the same amount as the velocities of the frame of reference. The force is proportional to the angular velocity (which determines the relative speed of two different points in the rotating frame of reference), and to the component of the velocity of the object in a plane perpendicular to the axis of rotation (which determines how quickly it moves between those points). This also gives a term

−

Ω

×

v

{\displaystyle -{\boldsymbol {\Omega }}\times {\boldsymbol {v}}}

.

text: Length scales and the Rossby number[edit]

text:
The time, space and velocity scales are important in determining the importance of the Coriolis force. Whether rotation is important in a system can be determined by its Rossby number, which is the ratio of the velocity, U, of a system to the product of the Coriolis parameter,

f
=
2
ω
sin

φ

{\displaystyle f=2\omega \sin \varphi \,}

, and the length scale, L, of the motion:

text: The Rossby number is the ratio of inertial to Coriolis forces. A small Rossby number indicates a system is strongly affected by Coriolis forces, and a large Rossby number indicates a system in which inertial forces dominate. For example, in tornadoes, the Rossby number is large, in low-pressure systems it is low, and in oceanic systems it is around 1. As a result, in tornadoes the Coriolis force is negligible, and balance is between pressure and centrifugal forces. In low-pressure systems, centrifugal force is negligible and balance is between Coriolis and pressure forces. In the oceans all three forces are comparable.[25]

text: An atmospheric system moving at U = 10 m/s (22 mph) occupying a spatial distance of L = 1,000 km (621 mi), has a Rossby number of approximately 0.1.

text: A baseball pitcher may throw the ball at U = 45 m/s (100 mph) for a distance of L = 18.3 m (60 ft). The Rossby number in this case would be 32,000.

text: Baseball players don't care about which hemisphere they're playing in. However, an unguided missile obeys exactly the same physics as a baseball, but can travel far enough and be in the air long enough to experience the effect of Coriolis force. Long-range shells in the Northern Hemisphere landed close to, but to the right of, where they were aimed until this was noted. (Those fired in the Southern Hemisphere landed to the left.) In fact, it was this effect that first got the attention of Coriolis himself.[26][27][28]

text: Simple cases[edit]

text: This section may be too long to read and navigate comfortably. Please consider splitting content into sub-articles, condensing it, or adding or removing subheadings. (March 2014)

text: Cannon on turntable[edit]

text: This section may be too technical for most readers to understand. Please help improve it to make it understandable to non-experts, without removing the technical details. (June 2010) (Learn how and when to remove this template message)

text: The animation at the top of this article is a classic illustration of Coriolis force. Another visualization of the Coriolis and centrifugal forces is this animation clip.

text: Given the radius R of the turntable in that animation, the rate of angular rotation ω, and the speed of the cannonball (assumed constant) v, the correct angle θ to aim so as to hit the target at the edge of the turntable can be calculated.

text: The inertial frame of reference provides one way to handle the question: calculate the time to interception, which is tf = R / v . Then, the turntable revolves an angle ω tf in this time. If the cannon is pointed an angle θ = ω tf = ω R / v, then the cannonball arrives at the periphery at position number 3 at the same time as the target.

text: No discussion of Coriolis force can arrive at this solution as simply, so the reason to treat this problem is to demonstrate Coriolis formalism in an easily visualized situation.

text: Trajectory in the inertial frame[edit]

text: The trajectory in the inertial frame (denoted A) is a straight line radial path at angle θ. The position of the cannonball in (x, y) coordinates at time t is:

text: In the turntable frame (denoted B), the x- y axes rotate at angular rate ω, so the trajectory becomes:

text: and three examples of this result are plotted in the figure.

text: Accelerations[edit]

text: Components of acceleration[edit]

text: To determine the components of acceleration, a general expression is used from the article fictitious force:

text: in which the term in Ω × vB is the Coriolis acceleration and the term in Ω × ( Ω × rB) is the centrifugal acceleration. The results are (let α = θ − ωt):

text: Producing accelerations[edit]

text: Producing a centrifugal acceleration:

text: Also:

text: producing a Coriolis acceleration:

text: These accelerations are shown in the diagrams for a particular example.

text: It is seen that the Coriolis acceleration not only cancels the centrifugal acceleration, but together they provide a net "centripetal", radially inward component of acceleration (that is, directed toward the center of rotation):[29]

text: and an additional component of acceleration perpendicular to rB (t):

text: The "centripetal" component of acceleration resembles that for circular motion at radius rB, while the perpendicular component is velocity dependent, increasing with the radial velocity v and directed to the right of the velocity. The situation could be described as a circular motion combined with an "apparent Coriolis acceleration" of 2ωv. However, this is a rough labelling: a careful designation of the true centripetal force refers to a local reference frame that employs the directions normal and tangential to the path, not coordinates referred to the axis of rotation.

text: These results also can be obtained directly by two time differentiations of rB (t). Agreement of the two approaches demonstrates that one could start from the general expression for fictitious acceleration above and derive the trajectories shown here. However, working from the acceleration to the trajectory is more complicated than the reverse procedure used here, which is made possible in this example by knowing the answer in advance.

text: As a result of this analysis an important point appears: all the fictitious accelerations must be included to obtain the correct trajectory. In particular, besides the Coriolis acceleration, the centrifugal force plays an essential role. It is easy to get the impression from verbal discussions of the cannonball problem, which focus on displaying the Coriolis effect particularly, that the Coriolis force is the only factor that must be considered,[30] but that is not so.[31] A turntable for which the Coriolis force is the only factor is the parabolic turntable. A somewhat more complex situation is the idealized example of flight routes over long distances, where the centrifugal force of the path and aeronautical lift are countered by gravitational attraction.[32][33]

text: Tossed ball on a rotating carousel[edit]

text: The figure illustrates a ball tossed from 12:00 o'clock toward the center of a counter-clockwise rotating carousel. On the left, the ball is seen by a stationary observer above the carousel, and the ball travels in a straight line to the center, while the ball-thrower rotates counter-clockwise with the carousel. On the right the ball is seen by an observer rotating with the carousel, so the ball-thrower appears to stay at 12:00 o'clock. The figure shows how the trajectory of the ball as seen by the rotating observer can be constructed.

text: On the left, two arrows locate the ball relative to the ball-thrower. One of these arrows is from the thrower to the center of the carousel (providing the ball-thrower's line of sight), and the other points from the center of the carousel to the ball.(This arrow gets shorter as the ball approaches the center.) A shifted version of the two arrows is shown dotted.

text: On the right is shown this same dotted pair of arrows, but now the pair are rigidly rotated so the arrow corresponding to the line of sight of the ball-thrower toward the center of the carousel is aligned with 12:00 o'clock. The other arrow of the pair locates the ball relative to the center of the carousel, providing the position of the ball as seen by the rotating observer. By following this procedure for several positions, the trajectory in the rotating frame of reference is established as shown by the curved path in the right-hand panel.

text: The ball travels in the air, and there is no net force upon it. To the stationary observer the ball follows a straight-line path, so there is no problem squaring this trajectory with zero net force. However, the rotating observer sees a curved path. Kinematics insists that a force (pushing to the right of the instantaneous direction of travel for a counter-clockwise rotation) must be present to cause this curvature, so the rotating observer is forced to invoke a combination of centrifugal and Coriolis forces to provide the net force required to cause the curved trajectory.

text: Bounced ball[edit]

text: The figure describes a more complex situation where the tossed ball on a turntable bounces off the edge of the carousel and then returns to the tosser, who catches the ball. The effect of Coriolis force on its trajectory is shown again as seen by two observers: an observer (referred to as the "camera") that rotates with the carousel, and an inertial observer. The figure shows a bird's-eye view based upon the same ball speed on forward and return paths. Within each circle, plotted dots show the same time points. In the left panel, from the camera's viewpoint at the center of rotation, the tosser (smiley face) and the rail both are at fixed locations, and the ball makes a very considerable arc on its travel toward the rail, and takes a more direct route on the way back. From the ball tosser's viewpoint, the ball seems to return more quickly than it went (because the tosser is rotating toward the ball on the return flight).

text: On the carousel, instead of tossing the ball straight at a rail to bounce back, the tosser must throw the ball toward the right of the target and the ball then seems to the camera to bear continuously to the left of its direction of travel to hit the rail (left because the carousel is turning clockwise). The ball appears to bear to the left from direction of travel on both inward and return trajectories. The curved path demands this observer to recognize a leftward net force on the ball. (This force is "fictitious" because it disappears for a stationary observer, as is discussed shortly.) For some angles of launch, a path has portions where the trajectory is approximately radial, and Coriolis force is primarily responsible for the apparent deflection of the ball (centrifugal force is radial from the center of rotation, and causes little deflection on these segments). When a path curves away from radial, however, centrifugal force contributes significantly to deflection.

text: The ball's path through the air is straight when viewed by observers standing on the ground (right panel). In the right panel (stationary observer), the ball tosser (smiley face) is at 12 o'clock and the rail the ball bounces from is at position one (1). From the inertial viewer's standpoint, positions one (1), two (2), three (3) are occupied in sequence. At position 2 the ball strikes the rail, and at position 3 the ball returns to the tosser. Straight-line paths are followed because the ball is in free flight, so this observer requires that no net force is applied.

text: Applied to the Earth[edit]

text: An important case where the Coriolis force is observed is the rotating Earth. Unless otherwise stated, directions of forces and motion apply to the Northern Hemisphere.

text: Intuitive explanation[edit]

text: As the Earth turns around its axis, everything attached to it turns with it (imperceptibly to our senses). An object that is moving without being dragged along with this rotation travels in a straight motion over the turning Earth. From our rotating perspective on the planet, its direction of motion changes as it moves, bending in the opposite direction to our actual motion. When viewed from a stationary point in space directly above the north pole, any land feature in the Northern Hemisphere turns anticlockwise—and, fixing our gaze on that location, any other location in that hemisphere rotates around it the same way. The traced ground path of a freely moving body travelling from one point to another therefore bends the opposite way, clockwise, which is conventionally labeled as "right," where it will be if the direction of motion is considered "ahead," and "down" is defined naturally.

text: Rotating sphere[edit]

text: Consider a location with latitude φ on a sphere that is rotating around the north-south axis.[34] A local coordinate system is set up with the x axis horizontally due east, the y axis horizontally due north and the z axis vertically upwards. The rotation vector, velocity of movement and Coriolis acceleration expressed in this local coordinate system (listing components in the order east (e), north (n) and upward (u)) are:

text: When considering atmospheric or oceanic dynamics, the vertical velocity is small, and the vertical component of the Coriolis acceleration is small compared to gravity. For such cases, only the horizontal (east and north) components matter. The restriction of the above to the horizontal plane is (setting vu = 0):

text:
where

f
=
2
ω
sin

φ

{\displaystyle f=2\omega \sin \varphi \,}

 is called the Coriolis parameter.

text: By setting vn = 0, it can be seen immediately that (for positive φ and ω) a movement due east results in an acceleration due south. Similarly, setting ve = 0, it is seen that a movement due north results in an acceleration due east. In general, observed horizontally, looking along the direction of the movement causing the acceleration, the acceleration always is turned 90° to the right and of the same size regardless of the horizontal orientation.

text: As a different case, consider equatorial motion setting φ = 0°. In this case, Ω is parallel to the north or n-axis, and:

text: Accordingly, an eastward motion (that is, in the same direction as the rotation of the sphere) provides an upward acceleration known as the Eötvös effect, and an upward motion produces an acceleration due west.

text: Meteorology[edit]

text: Perhaps the most important impact of the Coriolis effect is in the large-scale dynamics of the oceans and the atmosphere. In meteorology and oceanography, it is convenient to postulate a rotating frame of reference wherein the Earth is stationary. In accommodation of that provisional postulation, the centrifugal and Coriolis forces are introduced. Their relative importance is determined by the applicable Rossby numbers. Tornadoes have high Rossby numbers, so, while tornado-associated centrifugal forces are quite substantial, Coriolis forces associated with tornadoes are for practical purposes negligible.[35]

text: Because surface ocean currents are driven by the movement of wind over the water's surface, the Coriolis force also affects the movement of ocean currents and cyclones as well. Many of the ocean's largest currents circulate around warm, high-pressure areas called gyres. Though the circulation is not as significant as that in the air, the deflection caused by the Coriolis effect is what creates the spiraling pattern in these gyres. The spiraling wind pattern helps the hurricane form. The stronger the force from the Coriolis effect, the faster the wind spins and picks up additional energy, increasing the strength of the hurricane.[36]

text: Air within high-pressure systems rotates in a direction such that the Coriolis force is directed radially inwards, and nearly balanced by the outwardly radial pressure gradient. As a result, air travels clockwise around high pressure in the Northern Hemisphere and anticlockwise in the Southern Hemisphere. Air around low-pressure rotates in the opposite direction, so that the Coriolis force is directed radially outward and nearly balances an inwardly radial pressure gradient.[37][citation needed]

text: Flow around a low-pressure area[edit]

text: If a low-pressure area forms in the atmosphere, air tends to flow in towards it, but is deflected perpendicular to its velocity by the Coriolis force. A system of equilibrium can then establish itself creating circular movement, or a cyclonic flow. Because the Rossby number is low, the force balance is largely between the pressure-gradient force acting towards the low-pressure area and the Coriolis force acting away from the center of the low pressure.

text: Instead of flowing down the gradient, large scale motions in the atmosphere and ocean tend to occur perpendicular to the pressure gradient. This is known as geostrophic flow.[38] On a non-rotating planet, fluid would flow along the straightest possible line, quickly eliminating pressure gradients. Note that the geostrophic balance is thus very different from the case of "inertial motions" (see below), which explains why mid-latitude cyclones are larger by an order of magnitude than inertial circle flow would be.

text: This pattern of deflection, and the direction of movement, is called Buys-Ballot's law. In the atmosphere, the pattern of flow is called a cyclone. In the Northern Hemisphere the direction of movement around a low-pressure area is anticlockwise. In the Southern Hemisphere, the direction of movement is clockwise because the rotational dynamics is a mirror image there.[39] At high altitudes, outward-spreading air rotates in the opposite direction.[40] Cyclones rarely form along the equator due to the weak Coriolis effect present in this region.[41]

text: Inertial circles[edit]

text:
An air or water mass moving with speed

v

{\displaystyle v\,}

 subject only to the Coriolis force travels in a circular trajectory called an 'inertial circle'. Since the force is directed at right angles to the motion of the particle, it moves with a constant speed around a circle whose radius

R

{\displaystyle R}

 is given by:

text:
where

f

{\displaystyle f}

 is the Coriolis parameter

2
Ω
sin

φ

{\displaystyle 2\Omega \sin \varphi }

, introduced above (where

φ

{\displaystyle \varphi }

 is the latitude). The time taken for the mass to complete a full circle is therefore

2
π

/

f

{\displaystyle 2\pi /f}

. The Coriolis parameter typically has a mid-latitude value of about 10−4 s−1; hence for a typical atmospheric speed of 10 m/s (22 mph) the radius is 100 km (62 mi), with a period of about 17 hours. For an ocean current with a typical speed of 10 cm/s (0.22 mph), the radius of an inertial circle is 1 km (0.6 mi). These inertial circles are clockwise in the Northern Hemisphere (where trajectories are bent to the right) and anticlockwise in the Southern Hemisphere.

text:
If the rotating system is a parabolic turntable, then

f

{\displaystyle f}

 is constant and the trajectories are exact circles. On a rotating planet,

f

{\displaystyle f}

 varies with latitude and the paths of particles do not form exact circles. Since the parameter

f

{\displaystyle f}

 varies as the sine of the latitude, the radius of the oscillations associated with a given speed are smallest at the poles (latitude = ±90°), and increase toward the equator.[42]

text: Other terrestrial effects[edit]

text: The Coriolis effect strongly affects the large-scale oceanic and atmospheric circulation, leading to the formation of robust features like jet streams and western boundary currents. Such features are in geostrophic balance, meaning that the Coriolis and pressure gradient forces balance each other. Coriolis acceleration is also responsible for the propagation of many types of waves in the ocean and atmosphere, including Rossby waves and Kelvin waves. It is also instrumental in the so-called Ekman dynamics in the ocean, and in the establishment of the large-scale ocean flow pattern called the Sverdrup balance.

text: Eötvös effect[edit]

text: The practical impact of the "Coriolis effect" is mostly caused by the horizontal acceleration component produced by horizontal motion.

text: There are other components of the Coriolis effect. Westward-travelling objects are deflected downwards (feel heavier), while Eastward-travelling objects are deflected upwards (feel lighter).[43] This is known as the Eötvös effect. This aspect of the Coriolis effect is greatest near the equator. The force produced by this effect is similar to the horizontal component, but the much larger vertical forces due to gravity and pressure mean that it is generally unimportant dynamically.

text: In addition, objects travelling upwards (i.e., out) or downwards (i.e., in) are deflected to the west or east respectively. This effect is also the greatest near the equator. Since vertical movement is usually of limited extent and duration, the size of the effect is smaller and requires precise instruments to detect. However, in the case of large changes of momentum, such as a spacecraft being launched into orbit, the effect becomes significant. The fastest and most fuel-efficient path to orbit is a launch from the equator that curves to a directly eastward heading.

text: Intuitive example[edit]

text: Imagine a train that travels through a frictionless railway line along the equator. Assume that, when in motion, it moves at the necessary speed to complete a trip around the world in one day (465 m/s).[44] The Coriolis effect can be considered in three cases: when the train travels west, when it is at rest, and when it travels east. In each case, the Coriolis effect can be calculated from the rotating frame of reference on Earth first, and then checked against a fixed inertial frame. The image below illustrates the three cases in an inertial frame as observed from a fixed point above Earth along its axis of rotation:

text: If one looks at this train from the fixed non-rotating frame on top of the center of the Earth, at that speed it remains stationary as the Earth spins beneath it. Hence, the only force acting on it is gravity and the reaction from the track. This force is greater (by 0.34%)[44] than the force that the passengers and the train experience when at rest (rotating along with Earth). This difference is what the Coriolis effect accounts for in the rotating frame of reference.

text: From the fixed inertial frame of reference above Earth, the train now rotates along with the rest of the Earth. 0.34% of the force of gravity provides the centripetal force needed to achieve the circular motion on that frame of reference. The remaining force, as measured by a scale, makes the train and passengers "lighter" than in the previous case.

text:
From the fixed inertial frame of reference above Earth, the train travelling east now rotates at twice the rate as when it was at rest—so the amount of centripetal force needed to cause that circular path increases leaving less force from gravity to act on the track. This is what the Coriolis term accounts for on the previous paragraph.
As a final check one can imagine a frame of reference rotating along with the train. Such frame would be rotating at twice the angular velocity as Earth's rotating frame. The resulting centrifugal force component for that imaginary frame would be greater. Since the train and its passengers are at rest, that would be the only component in that frame explaining again why the train and the passengers are lighter than in the previous two cases.

text: This also explains why high speed projectiles that travel west are deflected down, and those that travel east are deflected up. This vertical component of the Coriolis effect is called the Eötvös effect.[45]

text: The above example can be used to explain why the Eötvös effect starts diminishing when an object is travelling westward as its tangential speed increases above Earth's rotation (465 m/s). If the westward train in the above example increases speed, part of the force of gravity that pushes against the track accounts for the centripetal force needed to keep it in circular motion on the inertial frame. Once the train doubles its westward speed at 930 m/s that centripetal force becomes equal to the force the train experiences when it stops. From the inertial frame, in both cases it rotates at the same speed but in the opposite directions. Thus, the force is the same cancelling completely the Eötvös effect. Any object that moves westward at a speed above 930 m/s experiences an upward force instead. In the figure, the Eötvös effect is illustrated for a 10 kilogram object on the train at different speeds. The parabolic shape is because the centripetal force is proportional to the square of the tangential speed. On the inertial frame, the bottom of the parabola is centered at the origin. The offset is because this argument uses the Earth's rotating frame of reference. The graph shows that the Eötvös effect is not symmetrical, and that the resulting downward force experienced by an object that travels west at high velocity is less than the resulting upward force when it travels east at the same speed.

text: Draining in bathtubs and toilets[edit]

text: Contrary to popular misconception, water rotation in home bathrooms under normal circumstances is not related to the Coriolis effect or to the rotation of the Earth, and no consistent difference in rotation direction between toilet drainage in the Northern and Southern Hemispheres can be observed.[46][47][48][49] The formation of a vortex over the plug hole may be explained by the conservation of angular momentum: The radius of rotation decreases as water approaches the plug hole, so the rate of rotation increases, for the same reason that an ice skater's rate of spin increases as they pull their arms in. Any rotation around the plug hole that is initially present accelerates as water moves inward.

text: The Coriolis force still impacts the direction of the flow of water, but only minutely. Only if the water is so still that the effective rotation rate of the Earth is faster than that of the water relative to its container, and if externally applied torques (such as might be caused by flow over an uneven bottom surface) are small enough, the Coriolis effect may indeed determine the direction of the vortex. Without such careful preparation, the Coriolis effect is likely to be much smaller than various other influences on drain direction[50] such as any residual rotation of the water[51] and the geometry of the container.[52] Despite this, the idea that toilets and bathtubs drain differently in the Northern and Southern Hemispheres has been popularized by several television programs and films, including Escape Plan, Wedding Crashers, The Simpsons episode "Bart vs. Australia", Pole to Pole,[53][54] and The X-Files episode "Die Hand Die Verletzt".[55] Several science broadcasts and publications, including at least one college-level physics textbook, have also stated this.[56][57]

text: In 1908, the Austrian physicist Ottokar Tumlirz described careful and effective experiments that demonstrated the effect of the rotation of the Earth on the outflow of water through a central aperture.[58] The subject was later popularized in a famous 1962 article in the journal Nature, which described an experiment in which all other forces to the system were removed by filling a 6 ft (1.8 m) tank with 300 U.S. gal (1,100 L) of water and allowing it to settle for 24 hours (to allow any movement due to filling the tank to die away), in a room where the temperature had stabilized. The drain plug was then very slowly removed, and tiny pieces of floating wood were used to observe rotation. During the first 12 to 15 minutes, no rotation was observed. Then, a vortex appeared and consistently began to rotate in an anticlockwise direction (the experiment was performed in Boston, Massachusetts, in the Northern Hemisphere). This was repeated and the results averaged to make sure the effect was real. The report noted that the vortex rotated, "about 30,000 times faster than the effective rotation of the Earth in 42° North (the experiment's location)". This shows that the small initial rotation due to the Earth is amplified by gravitational draining and conservation of angular momentum to become a rapid vortex and may be observed under carefully controlled laboratory conditions.[59][60]

text: Ballistic trajectories[edit]

text: The Coriolis force is important in external ballistics for calculating the trajectories of very long-range artillery shells. The most famous historical example was the Paris gun, used by the Germans during World War I to bombard Paris from a range of about 120 km (75 mi). The Coriolis force minutely changes the trajectory of a bullet, affecting accuracy at extremely long distances. It is adjusted for by accurate long-distance shooters, such as snipers.[24] Unlike large-scale motions of air in the atmosphere or water in the ocean, a bullet's path is not constrained to be horizontal, and the vertical component of the Coriolis force is often more important than the horizontal component: westward shots hit low, and eastward shots hit high.

text: The effects of the Coriolis force on ballistic trajectories should not be confused with the curvature of the paths of missiles, satellites, and similar objects when the paths are plotted on two-dimensional (flat) maps, such as the Mercator projection. The projections of the three-dimensional curved surface of the Earth to a two-dimensional surface (the map) necessarily results in distorted features. The apparent curvature of the path is a consequence of the sphericity of the Earth and would occur even in a non-rotating frame.

text: Visualization of the Coriolis effect[edit]

text: To demonstrate the Coriolis effect, a parabolic turntable can be used. On a flat turntable, the inertia of a co-rotating object forces it off the edge. However, if the turntable surface has the correct paraboloid (parabolic bowl) shape (see the figure) and rotates at the corresponding rate, the force components shown in the figure make the component of gravity tangential to the bowl surface exactly equal to the centripetal force necessary to keep the object rotating at its velocity and radius of curvature (assuming no friction). (See banked turn.) This carefully contoured surface allows the Coriolis force to be displayed in isolation.[61][62]

text: Discs cut from cylinders of dry ice can be used as pucks, moving around almost frictionlessly over the surface of the parabolic turntable, allowing effects of Coriolis on dynamic phenomena to show themselves. To get a view of the motions as seen from the reference frame rotating with the turntable, a video camera is attached to the turntable so as to co-rotate with the turntable, with results as shown in the figure. In the left panel of the figure, which is the viewpoint of a stationary observer, the gravitational force in the inertial frame pulling the object toward the center (bottom ) of the dish is proportional to the distance of the object from the center. A centripetal force of this form causes the elliptical motion. In the right panel, which shows the viewpoint of the rotating frame, the inward gravitational force in the rotating frame (the same force as in the inertial frame) is balanced by the outward centrifugal force (present only in the rotating frame). With these two forces balanced, in the rotating frame the only unbalanced force is Coriolis (also present only in the rotating frame), and the motion is an inertial circle. Analysis and observation of circular motion in the rotating frame is a simplification compared to analysis or observation of elliptical motion in the inertial frame.

text: Because this reference frame rotates several times a minute rather than only once a day like the Earth, the Coriolis acceleration produced is many times larger and so easier to observe on small time and spatial scales than is the Coriolis acceleration caused by the rotation of the Earth.

text: In a manner of speaking, the Earth is analogous to such a turntable.[63] The rotation has caused the planet to settle on a spheroid shape, such that the normal force, the gravitational force and the centrifugal force exactly balance each other on a "horizontal" surface. (See equatorial bulge.)

text: The Coriolis effect caused by the rotation of the Earth can be seen indirectly through the motion of a Foucault pendulum.

text: Coriolis effects in other areas[edit]

text: Coriolis flow meter[edit]

text: A practical application of the Coriolis effect is the mass flow meter, an instrument that measures the mass flow rate and density of a fluid flowing through a tube. The operating principle involves inducing a vibration of the tube through which the fluid passes. The vibration, though not completely circular, provides the rotating reference frame that gives rise to the Coriolis effect. While specific methods vary according to the design of the flow meter, sensors monitor and analyze changes in frequency, phase shift, and amplitude of the vibrating flow tubes. The changes observed represent the mass flow rate and density of the fluid.[64]

text: Molecular physics[edit]

text: In polyatomic molecules, the molecule motion can be described by a rigid body rotation and internal vibration of atoms about their equilibrium position. As a result of the vibrations of the atoms, the atoms are in motion relative to the rotating coordinate system of the molecule. Coriolis effects are therefore present, and make the atoms move in a direction perpendicular to the original oscillations. This leads to a mixing in molecular spectra between the rotational and vibrational levels, from which Coriolis coupling constants can be determined.[65]

text: Gyroscopic precession[edit]

text: When an external torque is applied to a spinning gyroscope along an axis that is at right angles to the spin axis, the rim velocity that is associated with the spin becomes radially directed in relation to the external torque axis. This causes a Coriolis force to act on the rim in such a way as to tilt the gyroscope at right angles to the direction that the external torque would have tilted it. This tendency has the effect of keeping spinning bodies stably aligned in space.

text: Insect flight[edit]

text: Flies (Diptera) and some moths (Lepidoptera) exploit the Coriolis effect in flight with specialized appendages and organs that relay information about the angular velocity of their bodies.

text: Coriolis forces resulting from linear motion of these appendages are detected within the rotating frame of reference of the insects' bodies. In the case of flies, their specialized appendages are dumbbell shaped organs located just behind their wings called "halteres".[66]

text: The fly's halteres oscillate in a plane at the same beat frequency as the main wings so that any body rotation results in lateral deviation of the halteres from their plane of motion.[67]

text: In moths, their antennae are known to be responsible for the sensing of Coriolis forces in the similar manner as with the halteres in flies.[68] In both flies and moths, a collection of mechanosensors at the base of the appendage are sensitive to deviations at the beat frequency, correlating to rotation in the pitch and roll planes, and at twice the beat frequency, correlating to rotation in the yaw plane.[69][68]

text: Lagrangian point stability[edit]

text: In astronomy, Lagrangian points are five positions in the orbital plane of two large orbiting bodies where a small object affected only by gravity can maintain a stable position relative to the two large bodies. The first three Lagrangian points (L1, L2, L3) lie along the line connecting the two large bodies, while the last two points (L4 and L5) each form an equilateral triangle with the two large bodies. The L4 and L5 points, although they correspond to maxima of the effective potential in the coordinate frame that rotates with the two large bodies, are stable due to the Coriolis effect.[70] The stability can result in orbits around just L4 or L5, known as tadpole orbits, where trojans can be found. It can also result in orbits that encircle L3, L4, and L5, known as horseshoe orbits.


document_title: The Cosby Show

question_text: where did the cosbys live in new york

question_tokens: where did the cosbys live in new york

root

text: The Cosby Show

text: Premise[edit]

text: The show focuses on the Huxtable family, an upper middle-class African-American family, living in a brownstone in Brooklyn Heights, New York, at 10 Stigwood Avenue.[6] The patriarch is Cliff Huxtable, an obstetrician and son of a prominent jazz trombonist. The matriarch is his wife, attorney Clair Huxtable.[7]

tag: p

text: They have four daughters and one son: Sondra, Denise, Theo, Vanessa, and Rudy. Despite its comedic tone, the show sometimes involves serious subjects, like Theo's experiences dealing with dyslexia,[8] inspired by Cosby's dyslexic son, Ennis.[9] The show also deals with teen pregnancy when Denise's friend, Veronica (Lela Rochon), becomes pregnant.[10]

text: Episodes[edit]

text:
Season
Episodes
Originally aired
Nielsen ratings[11]

First aired
Last aired
Rank
Rating
Tied with

1
24
September 20, 1984 (1984-09-20)
May 9, 1985 (1985-05-09)
3
24.2
N/A

2
25
September 26, 1985 (1985-09-26)
May 15, 1986 (1986-05-15)
1
33.7
N/A

3
25
September 25, 1986 (1986-09-25)
May 7, 1987 (1987-05-07)
1
34.9
N/A

4
24
September 24, 1987 (1987-09-24)
April 28, 1988 (1988-04-28)
1
27.8
N/A

5
26
October 6, 1988 (1988-10-06)
May 11, 1989 (1989-05-11)
1
25.6
N/A

6
26 + Special
September 21, 1989 (1989-09-21)
May 3, 1990 (1990-05-03)
1
23.1
Roseanne

7
26
September 20, 1990 (1990-09-20)
May 2, 1991 (1991-05-02)
5
17.1
N/A

8
25
September 19, 1991 (1991-09-19)
April 30, 1992 (1992-04-30)
18
15.0
N/A

tag: table

text: Pilot[edit]

text: The Cosby Show pilot episode uses the same title sequence as the rest of the first season, and is widely regarded as the first episode. However, it is notable for a number of differences from the remainder of the series.

text: In the pilot, the Huxtables have only four children.[12] Following the pilot, the Huxtables have five children, with the addition of their eldest daughter, Sondra (Sabrina Le Beauf), who is mentioned in episode four and appears first in episode 11. The character was created when Bill Cosby wanted the show to express the accomplishment of successfully raising a child (i.e., a college graduate).[13]

text: Whitney Houston was considered for the role of Sondra Huxtable. Houston, however, was unable to commit to the full-time television production schedule in the NBC contract, as she was intending to be a full-time music recording artist.[14][15]

text: Most of the story in the pilot presentation is taken from Bill Cosby's classic comedy film, Bill Cosby: Himself. Cosby's character is called "Clifford" in the early episodes of the first season (as evidenced by his name plate on the exterior of the Huxtable home). His name was later switched to "Heathcliff."

text: Additionally, Vanessa refers to Theo as "Teddy" twice in the dining room scene. The interior of the Huxtables' home features an entirely different living room from subsequent episodes, and different color schemes in the dining room and the master bedroom. Throughout the remainder of the series, the dining room is reserved for more formal occasions.

text: Background and production[edit]

text: Conception and development[edit]

text: In the early 1980s, Marcy Carsey and Tom Werner, two former executives at ABC, left the network to start their own production company.[16] At ABC, they had overseen sitcoms such as Mork & Mindy, Three's Company, and Welcome Back, Kotter. The two decided that to get a sitcom to sell for their fledgling company, they needed a big name behind it. Bill Cosby, who starred in two failed sitcoms during the 1970s, produced award-winning stand-up comedy albums, and had roles in several different films, was relatively quiet during the early 1980s.

text: Outside of his work on his cartoon series Fat Albert and the Cosby Kids, Cosby was doing little in film or television, but Carsey and Werner were fans of Cosby's stand-up comedy and thought it would be the perfect material for a family sitcom.[17]

text: Cosby originally proposed that the couple should both have blue-collar jobs, with the father a limousine driver,[18] who owned his own car, and the mother an electrician.[19] With advice from his wife Camille Cosby, though, the concept was changed so that the family was well-off financially, with the mother a lawyer and the father a physician.[20][21]

text: Cosby wanted the program to be educational, reflecting his own background in education. He also insisted that the program be taped in New York City instead of Los Angeles, where most television programs were taped.[22] The Huxtable home exterior was filmed at 10 St. Luke's Place near 7th Avenue in Manhattan's Greenwich Village (although in the show, the residence was the fictional "10 Stigwood Avenue").[23]

text: Production notes[edit]

text: The earliest episodes of the series were videotaped at NBC's Brooklyn studios (now owned by JC Studios).[24] The network later sold that building, and production moved to the Kaufman Astoria Studios in Queens.[25] Even though the show was set to take place in Brooklyn, the exterior façade was actually of a brownstone townhouse located in Manhattan's Greenwich Village at 10 Leroy Street/ 10 St. Luke's Place.[26] The pilot was filmed in May 1984, with season one's production commencing in July 1984, and the first taping on August 1, 1984 (Goodbye Mr. Goldfish).[27][28]

text: During its original run on NBC, it was one of five successful sitcoms on the network that featured predominantly African-American casts. The other sitcoms were 227 (1985–90), Amen (1986–91), Cosby Show spin-off A Different World (1987–93), and The Fresh Prince of Bel-Air (1990–96). Four other NBC sitcoms of that time also featured Black actors and actresses in lead starring or supporting roles--Nell Carter and Telma Hopkins on Gimme a Break (1981−87); Leonard Lightfoot, and later Franklyn Seales and Alfonso Ribeiro on Silver Spoons (1982−86); Kim Fields on The Facts of Life (1979−88), and Gary Coleman and Todd Bridges on Diff'rent Strokes (1978–85).

text: Although the cast and characters were predominantly African American,[29] the program was unusual in that issues of race were rarely mentioned when compared to other situation comedies of the time, such as The Jeffersons.[30] However, The Cosby Show had African-American themes, such as the Civil Rights Movement, and it frequently promoted African-American and African culture represented by artists and musicians such as Jacob Lawrence, Miles Davis, James Brown, B.B. King, Stevie Wonder, Sammy Davis, Jr., Lena Horne, Duke Ellington, Dizzy Gillespie, and Miriam Makeba.[31]

text: The show's spin off, A Different World, dealt with issues of race more often.[32] The series finale (taped on March 6, 1992)[33] aired during the 1992 Los Angeles riots, with Cosby quoted in media at the time pleading for peace.[34][35]

text: During the third season of the show, actress Phylicia Rashad was pregnant with her daughter Condola Rashād. Rather than write this pregnancy into the character of Claire Huxtable, the producers simply greatly reduced Rashad's scenes or filmed in such a way that her pregnancy was not noticeable.[36]

text: Another pregnancy of one of the main stars, that of Lisa Bonet, almost caused the actress to be fired, especially coming in the wake of appearing in the film Angel Heart, which contained graphic sexual scenes with actor Mickey Rourke. Bill Cosby strongly disapproved of Bonet appearing in the film, but she was allowed to retain her role on A Different World until returning to The Cosby Show after her pregnancy. Tensions remained, however, and Bonet was eventually fired from the show in April 1991.[37]

text: Theme song and opening sequence[edit]

text: The show's theme music, "Kiss Me", was composed by Stu Gardner and Bill Cosby.[38] Seven versions of this theme were used during the run of the series, making it one of the few television series to use multiple versions of the same theme song over the course of a series. For season four, the theme song music was performed by musician Bobby McFerrin.[39]

text: Due to legal complications regarding the background mural, the opening for season seven (filmed in August 1990) was replaced with the one from the previous season.[40][41][42] The original season-seven opening, with slight modifications, returned to use in the beginning of season eight.

text: Cast and characters[edit]

text:
Actor
Character
Seasons

1
2
3
4
5
6
7
8

Bill Cosby
Dr. Heathcliff "Cliff" Huxtable
Main

Phylicia Rashad*
Clair Olivia Hanks Huxtable
Main

Lisa Bonet
Denise Huxtable–Kendall
Main
Recurring
Main

Malcolm-Jamal Warner
Theodore "Theo" Huxtable
Main

Tempestt Bledsoe
Vanessa Huxtable
Main

Keshia Knight Pulliam
Rudith "Rudy" Lilian Huxtable
Main

Sabrina Le Beauf
Sondra Huxtable–Tibideaux
Recurring
Main

Geoffrey Owens
Elvin Tibideaux

Recurring
Main

Joseph C. Phillips+
Lt. Martin Kendall

Main
Recurring

Raven-Symoné
Olivia Kendall

Main

Erika Alexander
Pamela "Pam" Tucker

Main

text: *Phylicia Rashad was credited as "Phylicia Ayers-Allen" during season one and the first fourteen episodes of season two.

text: +Prior to joining the cast as a regular, Joseph C. Phillips appears as Daryl, a potential boyfriend for Sondra in season two (episode: "Cliff in Love").

text: Reception and Legacy[edit]

text: The show's portrayal of a successful, stable black family was praised by some for breaking racial stereotypes and showing another part of the African-American experience.[43][44] However, it was criticized by others, including Henry Louis Gates, for allowing white audiences to think that racism and poverty were problems of the past.[45] As a result of the sexual assault allegations against Cosby, Malcolm-Jamal Warner has stated that the show's legacy is "tarnished".[46]

text: Broadcast history and ratings[edit]

text: The Cosby Show aired on Thursdays at 8:00 pm for all eight seasons.[47] In its first season, the show was the beginning of a Thursday NBC schedule that was followed by Family Ties, Cheers, Night Court, and Hill Street Blues.[48]

text: The Cosby Show is one of three television programs (All in the Family and American Idol being the others) that were number one in the Nielsen ratings for five consecutive seasons.[49][50][51]

text:
Season
Season premiere
Season finale
Time slot (ET)
Ranking
Households
(in millions)

1
1984–85
September 20, 1984
May 9, 1985
Thursday at 8:00 pm
No. 3[52]
20.546 (24.2 rating)[52]

2
1985–86
September 26, 1985
May 15, 1986
No. 1[53]
28.948 (33.7 rating)[53]

3
1986–87
September 25, 1986
May 7, 1987
No. 1[54]
30.503 (34.9 rating)[54]

4
1987–88
September 24, 1987
April 28, 1988
No. 1[55]
30.502 (34.9 rating)[55]

5
1988–89
October 6, 1988
May 11, 1989
No. 1[56]
23.142 (25.6 rating)[56]

6
1989–90
September 21, 1989
May 3, 1990
No. 1 (tie with Roseanne)[57]
21.275 (23.1 rating)[57]

7
1990–91
September 20, 1990
May 2, 1991
No. 5[58]
15.920 (17.1 rating)[58]

8
1991–92
September 19, 1991
April 30, 1992
No. 18[59]
13.815 (15.0 rating)[59]

text: Syndication[edit]

text: Carsey-Werner Distribution handles domestic distribution, while CBS Television Distribution handles international distribution of the series, and has done so since 1997. In the United States, The Cosby Show began its television syndication run in September 1988 in broadcast syndication, shortly before the show's fifth-season premiere, and was at the time distributed by Viacom; many stations that carried the series were Big Three network affiliates, though since the mid 1990s, the show has largely begun airing on independent stations and minor network affiliates.

text: Fort Worth, Texas-based independent station, KTVT, carried the series until 1995, when it ceased operating as a regional cable superstation and became an affiliate of CBS. TBS, then a national cable superstation, carried the series for nearly a decade beginning in 1999. Fellow superstation WGN America began carrying the series shortly thereafter, and continued to until September 2010. Viacom's Nick at Nite began airing reruns of the series in March 2002, and its sister network TV Land began airing reruns in 2004, making The Cosby Show one of the few series that were shown on both Nick at Nite and TV Land at the same time.

text: Pulled from broadcasting[edit]

text: Reruns of The Cosby Show have been pulled as a result of sexual assault allegations against Cosby. In November 2014, TV Land pulled the series from its lineup.[60][61] In December 2014, the Magic Johnson owned network Aspire removed the show from its lineup.[62]

text: BET's Centric (another Viacom unit) stopped airing reruns of The Cosby Show. At the same time, barter syndication The Program Exchange ceased distributing the latter show.[63][64] Bounce TV resumed airing the series in December 2016[65] but pulled the show the day Cosby was convicted of sexual assault[66] On May 19, 2017, TV One began airing reruns of the show.

text: Spin-off[edit]

text: The Cosby Show's producers created a spin-off series called A Different World that was built around the "Denise" character (portrayed by actress Lisa Bonet), the second of the Huxtables' four daughters. Initially, the new program dealt with Denise's life at Hillman College, the fictional historically black college from which her father, mother, and paternal grandfather had graduated.

text: Denise was written out of A Different World after its inaugural season, due to Bonet's pregnancy, and the following season was revamped, with the addition of director Debbie Allen (Phylicia Rashad's sister) and new characters.[67] Denise later became a recurring character on The Cosby Show for seasons four and five, and a regular again in seasons six and seven.

text: Awards and honors[edit]

text: Awards won[edit]

text: Emmy Awards[68]

text:
Outstanding Comedy Series (1985)
Outstanding Writing in a Comedy Series (1985) – Michael Leeson and Ed. Weinberger for the pilot episode
Outstanding Directing in a Comedy Series (1985) – Jay Sandrich for "The Younger Woman"
Outstanding Directing in a Comedy Series (1986) – Jay Sandrich for "Denise's Friend"
Outstanding Guest Performer in a Comedy Series (1986) – Roscoe Lee Browne for "The Card Game"
Outstanding Editing for a Series – Multi-Camera Production (1986) – Henry Chan for "Full House"

text: Golden Globe Awards

text:
Best TV Series – Comedy (1985)
Best Performance by an Actor in a TV Series – Comedy – Bill Cosby (1985, 1986) 2 wins

text: NAACP Image Awards

text:
Outstanding Comedy Series (1988)
Outstanding Actress in a Comedy Series – Phylicia Rashad (1988, 1989) 2 wins
Outstanding Actor in a Comedy Series – Bill Cosby (1989, 1993) 2 wins

text: Peabody Award (1986)

text: People's Choice Awards

text:
Favorite New TV Comedy Program (1985)
Favorite Male Performer in a New TV Program – Bill Cosby (1985)
Favorite Female Performer in a New TV Program – Phylicia Rashad (1985)
Favorite TV Comedy Program (1985–89) 5 wins
Favorite Male TV Performer – Bill Cosby (1986–92) 7 wins
Favorite All-Around Male Entertainer – Bill Cosby (1986–88, 1990–91) 5 wins
Favorite Young TV Performer – Keshia Knight Pulliam (1988)
All-Time Favorite TV Program (1989)
Favorite Female TV Performer – Phylicia Rashad (1989)
Favorite All-Around Male Star – Bill Cosby (1989)
Favorite TV Comedy Series (1990, 1992) 2 wins

text: Nominations[edit]

text: Emmy Awards[68]

text:
Outstanding Technical Direction/Electronic Camerawork/video control for a series – 1985
Outstanding Live and Tape Sound Mixing and Sound Effects for a series – (1985) 2 nominations
Outstanding Writing in a Comedy Series – (1985–86)
Outstanding Lead Actress in a Comedy Series – Phylicia Rashad (1985–86) 2 nominations
Outstanding Comedy Series (1986–87) 2 nominations
Outstanding Supporting Actress in a Comedy Series – Lisa Bonet (1986)
Outstanding Supporting Actress in a Comedy Series – Keshia Knight Pulliam (1986)
Outstanding Supporting Actor in a Comedy Series – Malcolm-Jamal Warner (1986)
Outstanding Sound Mixing for a Comedy Series or a Special – (1986–87)
Outstanding Editing for a Series (multi camera production) – (1987)
Outstanding Directing in a Comedy Series – Jay Sandrich (1987)
Outstanding Comedy Series – (1987)
Outstanding Guest Performer in a Comedy Series – Eileen Heckart (1988)
Outstanding Guest Actor in a Comedy Series – Sammy Davis Jr. (1989)

text: Golden Globe Awards

text:
Best TV Series – Comedy – (1986–1987) – Two nominations
Best Performance by an Actor in a TV Series – Comedy – Bill Cosby (1987)

text: Other honors[edit]

text:
1993: TV Guide named The Cosby Show the All-Time Best Family Show in its issue celebrating 40 years of television.[69]
1997: TV Guide ranked the episode "Happy Anniversary" #54 on their list of the 100 Greatest Episodes of All Time[70]
1999: Entertainment Weekly placed show's debut at #24 in its list of the "100 Greatest Moments in Television"[71]
2002: TV Guide placed The Cosby Show at #28 in its list of the 50 Greatest TV Shows of All Time[72]
2004: TV Guide ranked Cliff Huxtable number 1 on its 50 Greatest TV Dads of All Time list[73]
2004: Bravo ranked Cliff Huxtable #44 on its list of the 100 Greatest TV Characters[74]
2007: Time magazine placed the show on its unranked list of "100 Best TV Shows of All-TIME"[75]
2007: USA Today's web site ranked the show as #8 in its list of the "top 25 TV moments of the past quarter century"[76]
2008: Entertainment Weekly selected Cliff Huxtable as the Dad for "The Perfect TV Family"[77]
2013: TV Guide ranked The Cosby Show #26 on its list of the 60 Best Series.[78]

text: Albums[edit]

text: Two albums were produced that included various theme and background music from the show. The albums were presented by longtime Cosby collaborator Stu Gardner. They were:

text:
A House Full of Love: Music from The Cosby Show (1986)
Total Happiness (Music from the Bill Cosby Show, Vol. II) (1987)

text: In popular culture[edit]

text: During the series' run, the character of Cliff Huxtable frequently wore an array of knit sweaters that were often brightly colored and featured abstract, asymmetrical patterns or themes. The sweaters were erroneously thought to be designed by the Australian clothing company Coogi, but were actually designed by Dutchman Koos Van Den Akker.[79][80][81]

text: They were dubbed "Cosby sweaters", a term that is used to describe sweaters that are generally deemed garish and unappealing.[82][83] In May 2008, Cosby's daughter Evin auctioned a batch of the sweaters that her father had kept on eBay. The proceeds of the sales went to the Hello Friend/Ennis William Cosby Foundation, a non profit charity named for Ennis Cosby. Ennis, Cosby's only son, was murdered in January 1997.[84]

text: The character of Dr. Hibbert, who is featured on the long running animated sitcom The Simpsons, is modelled after Dr. Cliff Huxtable. The Simpsons writing staff decided to make Dr. Hibbert a parody of Cliff Huxtable after the Fox network moved The Simpsons to Thursday nights airing opposite the top rated The Cosby Show.[85]

text: In the Teen Titans Go! episode "Oil Drums", Starfire says "I would like to watch The Crosby Pudding Half Hour Show of Sweaters. Theo, get your glorp-nops off the kitchen table. Rudy!"

text: DVD releases[edit]

text: All eight seasons of The Cosby Show have been released on DVD in Region 1. Seasons one and two were released by UrbanWorks which was subsequently acquired by First Look Studios, who then released the remaining six seasons. Seasons One and Two contain special features, including the ninety minute retrospective documentary entitled The Cosby Show: A Look Back, which aired on NBC in May 2002.

text: It contains interviews with cast members, bloopers, deleted scenes and audition footage. In December 2010, First Look Studios filed bankruptcy, and all its assets were subsequently acquired by Millennium Entertainment, who also took over distribution of The Cosby Show DVD releases. As of 2013, these releases have been discontinued, and are now out of print.

text: On November 5, 2013, it was announced that Mill Creek Entertainment had acquired the rights to the series. They have subsequently re released all eight seasons on DVD.[86][87][88][89] On September 1, 2015, Mill Creek released a sixteen disc complete series set entitled The Cosby Show – The Complete Series.[90]

text: In Region 4, Magna Pacific has released all eight seasons on DVD in Australia and New Zealand. The first two seasons have similar artwork to the North American copies, although season two is red rather than blue. Each Australian cover also features the tagline "In a house full of love, there is always room for more".

text: Universal Studios Home Entertainment has released Seasons 1 to 4 in Region 2 (United Kingdom).

text:
DVD title
Ep #
Release dates

Region 1
Region 2
Region 4

Season 1
24
August 2, 2005
January 21, 2014 (re release)
May 19, 2008
October 4, 2006

Season 2
25
March 7, 2006
January 21, 2014 (re release)
August 25, 2008
February 7, 2007

Season 3
25
June 5, 2007
April 15, 2014 (re release)
Oct 13, 2008
April 4, 2007

Season 4
24
June 5, 2007
April 15, 2014 (re release)
Feb 9, 2009
November 7, 2007

Season 5
26
November 6, 2007
January 6, 2015 (re release)

March 5, 2008

Season 6
26
November 6, 2007
January 6, 2015 (re release)

July 9, 2008

Season 7
26
April 8, 2008
June 16, 2015 (re release)

January 13, 2010

Season 8
25
April 8, 2008
June 16, 2015 (re release)

January 13, 2010

25th Anniversary
Commemorative Edition
202
November 11, 2008
September 1, 2015 (re release)

Collector's Edition
202

August 6, 2014

text: Note: The Millennium Entertainment release of season one contains the edited versions of the episodes aired in syndication. However, all subsequent DVD releases (including the complete series set) contain the original, uncut broadcast versions. In 2011, Millennium quietly released season one uncut in Region 1, which featured the special features from The Complete Series set.