# coriolis effect

## coriolis effect

The Coriolis effect describes how Earths rotation steers winds and surface ocean currents (Figure 1.1). Coriolis causes freely moving objects to appear to move to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. The objects themselves are actually moving straight, but the Earth is rotating beneath them, so they seem to bend or curve. Thats why it is incorrect to call Coriolis a force. It is not forcing anything to happen! An example might make the Coriolis effect easier to visualize. If an airplane flies 500 miles due north, it will not arrive at the city that was due north of it when it began its journey. Over the time it takes for the airplane to fly 500 miles, that city moved, along with the Earth it sits on. The airplane will therefore arrive at a city to the west of the original city (in the Northern Hemisphere), unless the pilot has compensated for the change. So to reach his intended destination, the pilot must also veer right while flying north. As wind or an ocean current moves, the Earth spins underneath it. As a result, an object moving north or south along the Earth will appear to move in a curve instead of in a straight line. Wind or water that travels toward the poles from the Equator is deflected to the east, while wind or water that travels toward the Equator from the poles gets bent to the west. The Coriolis effect bends the direction of surface currents to the right in the Northern Hemisphere and left in the Southern Hemisphere. The Coriolis effect causes winds and cur- rents to form circular patterns. The di- rection that they spin depends on the hemisphere that they are in. Coriolis effect is demonstrated using a metal ball and a rotating plate in this video. The ball moves in a circular path just like a freely moving particle of gas or liquid moves on the rotating Earth (5b). Click image to the left or use the URL below. URL:

## instructional diagrams

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## questions

the coriolis effect describes how

``````a) earths rotation steers the movement of air and water.

b) earths rotation goes in different directions in the northern and southern hemisphere.

-->  c) how earth moves beneath and water, causing it to appear that their motion is curved.

d) all of the above
``````

if a pilot wants to fly to a city that is 1000 miles due north of his starting city, he must fly

``````a) due north.

-->  b) north but also east.

c) north but also west.

d) due west.
``````

coriolis effect occurs because earth is rotating beneath a moving object.

``````-->  a) true

b) false
``````

freely moving objects appear to move to the right in the southern hemisphere.

``````a) true

-->  b) false
``````

you can tell which hemisphere youre in because water in a drain always spirals right in the northern hemisphere and left in the southern hemisphere.

``````a) true

-->  b) false
``````

coriolis is an effect, because it is not forcing the movement of objects to change, it just appears that the movement of objects is not straight.

``````-->  a) true

b) false
``````

in which direction will an ocean current that is traveling south from the north pole curve due to coriolis effect?

``````a) north

b) south

c) east

-->  d) west
``````

in which direction will an ocean current that is traveling north from the south pole curve due to coriolis effect?

``````a) north

b) south

c) east

-->  d) west
``````

in which direction will an airplane need to travel if it is flying from 45on 120ow (near the pacific ocean) to 45on 90ow (near the great lakes)?

``````a) east, but curving to the right.

b) east, but curving to the left.

-->  c) due east.

d) due west.
``````

an ocean current traveling across the north pacific ocean from west to east runs into north america. which direction does it go from there?

``````-->  a) it turns right.

b) if turns left.

c) it goes straight.

d) it goes back the way it came.
``````

## diagram questions

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