Chapter 17 Study Cards

Why do stars appear to be close together even though they are not?

We are looking at them from such a far distance that they appear close to one another.

How many stars did God create?

We don't know for sure. There are too many to count, though scientists have tried.

How long does it take for Earth to rotate one full turn?

Earth takes about 24 hours to rotate completely.

Why does the moon appear to change shape?

As the Sun shines on the moon, only part of this reflection is visible on Earth. The revolution of the moon causes the shape to change.

Why does earth seem to stand still?

Earth seems to stand still because it moves slowly and smoothly, and we are moving with it.

How long does it take for Earth to make one revolution around the Sun?

It takes Earth one year or about 365 days to revolve around the Sun.

Why do shadows change?

Shadows change because the earth rotates.

When the northern hemisphere is tilted toward the Sun, is it summer or winter there?

Summer

What is the closest star to Earth?

The Sun

lunar eclipse

The blocking of sunlight to the moon that occurs when Earth is directly between the sun and moon

Why can you not see stars during the day?

The sun is too bright.

What causes the seasons?

The tilt of Earth on its axis and Earth's revolution around the Sun causes the seasons to change.

What happens to stars as Earth rotates on its axis?

They move across the sky.

Which direction does Earth rotate?

West to East

constellations

a group of stars that forms a shape or pattern

axis

an imaginary line that passes through Earth's center and the North and South poles, about which Earth rotates

Ellipse

an oval shape that describes the shape of a planet's orbit around the Sun

What color does the moon appear to be during a lunar eclipse?

copper

solar eclipse

the blocking of sunlight to earth that occurs when the moon is directly between the sun and earth

revolution

the movement of one object around another object

eclipse

the passing of one object through the shadow of another

rotation

the spinning of Earth on its axis