CHAPTER 1

THE SOLAR

SYSTEM

WHAT CAUSES DAY AND NIGHT?

LESSON 2

Did you ever notice the sun move across the sky during the day?????

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

The sun does not really cross our sky, because the sun does not move.

It is the Earth that is moving.

It is because Earth moves that we experience something here on Earth.

It is ……

DAY

NIGHT&

Can you guess what it is?????

Yes, it is because

the Earth moves

the we have day

and night.

Remember…Earth is one of eight planets in our solar system.

Each of the planets in our solar system moves.

The spinning of the planets is called rotation.

It takes Earth about 24 hours to rotate, or spin, all the way around one time.

Once the Earth has spun around one complete time, we have experienced one day on Earth.

The sun shines all of the time.

But, it is not always shining on our part of the Earth.

The Earth rotates, or spins, counter clockwise.

The Rotation of Earth Causes Day & Night

When one side of the Earth faces the sun, that side is lighted, and it is daytime.

The other side of the Earth is dark, and it is nighttime.

WHAT CAUSES SEASONS?

LESSON 3

The Earth rotates on an imaginary line called an axis.

Earth tilts on this axis.

Earth moves in a path, or and orbit, around the sun.

It takes Earth one year to orbit the sun one time.

As the Earth orbits the sun, the seasons change.

A season is a time of year that has a certain kind of weather.

Earth Orbits the Sun

Earth is always tilted in the same direction.

When Earth is on one side of the sun, part of

the Earth faces the sun directly and get more

direct sunlight.

This part of the Earth is having summer.

Why the Seasons Change

As the Earth rotates, the tilt does not change.

Now the tilt causes this same part of Earth to face the sun on a slant.

Sunlight does not hit the Earth directly, so this part of Earth has winter.

So… Why do seasons

change???Seasons change because Earth is tilted and it orbits the sun. As the Earth orbits the sun, different parts of the Earth get more or less direct sunlight.

HOW DOES THE MOON MOVE AND CHANGE?

LESSON 4

The moon is the object that appears to be the largest in the night sky.

It seems to shine, but the moon does not really give off light of its own.

The light that we see coming from the moon, or moonlight, is really light from the sun being reflected by the moon.

MOONLIGHT

People have been studying space to discover things about it.

Astronauts are scientists who study space.

They help us learn new things about the sun, moon, stars, planets, and more.

The moon is a huge ball of rock that orbits the Earth.

It takes about 29 days for the moon to orbit Earth one time.

When we look at the moon, we may see some spots. These are holes called craters.

A crater is made when a large rock moving through space hits the moon.

THE MOON

moonlight

craters

The moon’s orbit around Earth makes the moon appear to change shape.

The moon’s orbit begins between the sun and Earth, so the side facing Earth is dark.

As the moon orbits Earth, we are able to see only the lighted part of the moon that is facing us.

THE MOON APPEARS TO CHANGE SHAPE