rotation of earth

foucaults pendulum

In 1851, a French scientist named Lon Foucault took an iron sphere and hung it from a wire. He pulled the sphere to one side and then released it, as a pendulum. Although a pendulum set in motion should not change its motion, Foucault observed that his pendulum did seem to change direction relative to the circle below. Foucault concluded that Earth was moving underneath the pendulum. People at that time already knew that Earth rotated on its axis, but Foucaults experiment was nice confirmation.

daynight cycle

Earth rotates once on its axis about every 24 hours. To an observer looking down at the North Pole, the rotation appears counterclockwise. From nearly all points on Earth, the Sun appears to move across the sky from east to west each day. Of course, the Sun is not moving from east to west at all; Earth is rotating. The Moon and stars also seem to rise in the east and set in the west. Earths rotation means that there is a cycle of daylight and darkness approximately every 24 hours, the length of a day. Different places experience sunset and sunrise at different times and the amount of daylight and darkness also differs by location. Shadows are areas where an object obstructs a light source so that darkness takes on the form of the object. On Earth, a shadow can be cast by the Sun, Moon, or (rarely) Mercury or Venus. Click image to the left or use the URL below. URL:

earths rotation

Imagine a line passing through the center of Earth that goes through both the North Pole and the South Pole. This imaginary line is called an axis. Earth spins around its axis, just as a top spins around its spindle. This spinning movement is called Earths rotation. An observer in space will see that Earth requires 23 hours, 59 minutes, and 4 seconds to make one complete rotation on its axis. But because Earth moves around the Sun at the same time that it is rotating, the planet must turn just a little bit more to reach the same place relative to the Sun. Hence the length of a day on Earth is actually 24 hours. At the Equator, the Earth rotates at a speed of about 1,700 km per hour, but at the poles the movement speed is nearly nothing.

instructional diagrams

The diagram shows the rotation of the Earth on its axis and how the Sun illuminates its surface. It helps us understand how day and night work. One rotation takes 24 hours, exactly the length of a day. Dividing the Earth into two parts along the Greenwich meridian, the part facing the Sun is illuminated by the daylight, whereas the other part is in the dark. By rotating, the part of the Earth in the dark ends up receiving the daylight and vice versa. When we say the Sun rises in the east it means that the east is facing the Sun. In the same way the west, which is the part in the dark, is where the Sun sets and the Moon and the stars appear. The changing of day and night is the result of the Earth rotating.

This diagram shows the earth rotating around its axis and the sun's rays hitting the earth. The side of the earth facing the sun has daylight. The side of the earth facing away from the sun is dark and has night. The earth rotates around its axis, once every 24 hours. Hence every part of the earth experiences day and night every 24 hours. There are 5 major circles of latitude that mark the diagram of the earth. There are the Arctic Circles, Tropic of Cancer, Equator, Tropic of Capricorn and the Antarctic Circle. The arctic circle is the northern most circle and the Antarctic circle is the southern most circle. The equator is the latitude in the middle that divides the earth into the northern and southern hemispheres. The tropic of cancer lies between the Arctic circle and the equator. The tropic of capricorn lies between the Antarctic circle and the equator.

questions

this french scientist used a pendulum, which help to confirm earths movement

``````a) einstein

b) newton

-->  c) foucault

d) galileo
``````

an imaginary line that runs through the center of the earth from the north to the south pole.

``````a) geographic pole

b) magnetic pole

-->  c) axis

d) equator
``````

the earth rotates on its axis every

``````a) 60 minutes

-->  b) 24 hours

c) 365 days

d) 60 seconds
``````

the sun appears to move across the sky from west to east each day.

``````a) true

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

a molecule at the equator rotates extremely fast, but a molecule at the south pole barely moves at all.

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

b) false
``````

these things differ by location:

``````a) sunrise and sunset.

b) the length of day and night.

c) the amount of daylight and darkness.

-->  d) all of these.
``````

a pendulum in paris confirmed the existence of

``````-->  a) earths rotation.

b) earths magnetic field.

c) the geocentric model

d) the equator.
``````

the earth rotational speed is about

``````-->  a) 700 km per hour

b) 1,000 km per hour

c) 1,700 km per hour

d) 2,000 km per hour
``````

``````-->  a) any strong light source.

b) only the sun.

c) only the sun and moon.

d) only mercury and venus.
``````

the direction that the stars appear to move across the sky is due to earths rotation.

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

b) false
``````

diagram questions

Which label refers to the Sun?

``````a. K

b. W

-->  c. T

d. H
``````

Which letter stands for the Equator?

``````-->  a. W

b. H

c. T

d. K
``````

Which letter represents the sun?

``````a. K

b. H

-->  c. T

d. W
``````

Which object is the sun?

``````-->  a. T

b. K

c. H

d. W
``````

Which represents the sun?

``````a. W

b. K

c. H

-->  d. T
``````

What does M represent?

``````a. DAY

b. NIGHT

c. SOUTH

-->  d. SUNLIGHT
``````

Which letter identifies sunlight?

``````-->  a. M

b. L

c. R

d. V
``````

Which Letter represents the sun rays?

``````a. L

b. Y

c. N

-->  d. D
``````

Which label refers to the Arctic Circle?

``````-->  a. H

b. F

c. T

d. N
``````

Which label shows the Tropic of Capricorn?

``````a. L

-->  b. T

c. N

d. J
``````

Which label shows the Earth Axis?

``````a. P

-->  b. Y

c. E

d. F
``````

Which part of the earth receives the highest intensity of solar energy?

``````a. TROPIC OF CAPRICORN

b. ARCTIC CIRCLE

c. TROPIC OF CANCER

-->  d. EQUATOR
``````

What does P represent?

``````-->  a. SUN RAYS

b. AXIS

c. MOON RAYS

d. EQUATOR
``````

What does the sun produce?

``````a. earth rays

b. sun rays

-->  c. light rays

d. dark rays
``````

``````a. Night

b. Day

-->  c. Light rays

d. Earth
``````

Which part(s) get the least rays?

``````a. The circles

b. The equator

c. The tropics

-->  d. The poles
``````

What region receives the sun's vertical rays?

``````a. Tropic of Capricorn

-->  b. Equator

c. Tropic of Cancer

d. North pole
``````

Which pole is closest to the arctic circle?

``````a. West

-->  b. North

c. South

d. East
``````

Which line of latitude lies between the equator and arctic circle?

``````a. North pole

-->  b. Tropic of cancer

c. Tropic of capricorn

d. Antarctic circle
``````

How many lines are on the earth?

``````a. 4

-->  b. 5

c. 6

d. 2
``````

Where is the equator in relation to the poles?

``````-->  a. In the middle

b. South

c. North

d. East
``````

What lies between Tropic of Cancer and Tropic of Capricorn?

``````a. Antartic circle

b. Artic circle

c. Sun's rays

-->  d. Equator
``````

Which area would experience a warmer climate during summer solstice?

``````a. Tropic of Capricorn

b. Antarctic

c. Equator

-->  d. Tropic of Cancer
``````

How many poles are there on the Earth?

``````a. three

b. four

c. one

-->  d. two
``````

If the suns rays are coming from the left, then what time of day is it on the right of the earth?

``````a. evening

b. day

c. both day and night

-->  d. Night
``````

What season is it at the Tropic of Capricorn at Winter Solstice?

``````-->  a. Summer

b. Fall

c. Winter

d. Spring
``````

On December 21st, What part of the earth gets no sunlight?

``````-->  a. North Pole

b. Tropic of Capricorn

c. Equator

d. Tropic of Cancer
``````

How many tropics surround the earth?

``````a. 5

-->  b. 2

c. 1

d. 3
``````

If the earth has rotated to the northern hemisphere in summer where does the vertical ray hit?

``````-->  a. It would hit the western side of the earth

b. The vertical ray would not be important

c. it would be on the same side

d. The vertical ray would be on the north pole
``````

Where are the sun rays stronger?

``````a. Arctic Circle

b. Tropics

-->  c. Equator

d. Antarctic Circle
``````

How many circles of latitude are pictured?

``````-->  a. Five

b. Four

c. Two

d. One
``````

What is the imaginary line at the center of the Earth called?

``````a. night

b. day

-->  c. equator

d. sun
``````

The sunlight hitting planet Earth results in which phenomenon?

``````-->  a. Day and Night cycle

b. Equator

c. Rotation

d. Translation
``````

How many stages of light do we have in the Earth?

``````a. 6

-->  b. 2

c. 1

d. 5
``````

On what side of the earth is a sunrise most likely happening?

``````-->  a. Right

b. Left

c. Equator

d. None
``````

What is the relationship between the true north and the magnetic north?

``````a. angle changes everyday

b. perpendicular to each other

c. the same angle

-->  d. slightly angled
``````

Which pole is currently in the dark?

``````a. West

b. North

c. East

-->  d. South
``````

When the Earth is in this position it is

``````a. Day in both Hemispheres

-->  b. Day in the Nothern Hemisphere

c. Night in the Nothern Hemisphere

d. Day in the Southern Hemisphere
``````

How many hemispheres does the earth have if divided in the equator?

``````a. 5

b. 3

c. 4

-->  d. 2
``````

What does the sun do in this diagram?

``````a. It lights up the entire earth.

b. It lights up a quarter of the earth.

-->  c. It lights up half of the earth

d. Not enough information provided.
``````

When the sunlight impacts the east in the west is?

``````-->  a. Night

b. Day

c. Evening

d. Morning
``````

Which direction is shown at the top of the earth?

``````a. South

-->  b. North

c. East

d. West
``````

What do people experience when sunlight does not hit their part of the world?

``````a. noon time

b. drought

c. day

-->  d. night
``````

Identify south

``````a. V

b. R

c. L

-->  d. D
``````