Grade 1
The Human Knowledge Project
Unit 16 — Earth, the Moon, and the Sun
Welcome back!
Have you ever looked up at the sky and wondered:
Why is the sky blue?
Why does the Moon change shape?
Why does the Sun rise every morning?
Today we will begin exploring our place in space.
Our Home: Earth
Earth is the planet where we live.
It has:
- land
- oceans
- rivers
- lakes
- mountains
- forests
- deserts
Earth is home to millions of different kinds of living things.
It is the only planet we know that supports life.
The Sun
The Sun is a star.
It gives Earth:
- light
- warmth
- energy
Without the Sun, plants could not grow.
Animals and people also depend on the Sun because all food ultimately comes from the energy it provides.
The Sun appears much larger than the stars because it is much closer to Earth.
The Moon
The Moon travels around Earth.
It does not make its own light.
Instead, it reflects light from the Sun.
Sometimes we see:
- a full Moon
- a half Moon
- a crescent Moon
The Moon's shape does not actually change.
We simply see different amounts of its sunlit side.
Day and Night
Earth slowly spins like a giant top.
This spinning is called rotation.
The side facing the Sun has daytime.
The side facing away from the Sun has nighttime.
One complete rotation takes about one day.
That is why every day has both daylight and darkness.
The Seasons
Earth also travels around the Sun.
One trip around the Sun takes one year.
As Earth travels, different parts of our planet receive different amounts of sunlight.
This helps create the four seasons:
- spring
- summer
- autumn (fall)
- winter
Looking at the Night Sky
On a clear night you may see:
- the Moon
- stars
- some planets
People have studied the night sky for thousands of years.
Astronomy is the science of studying objects in space.
There is always more to discover.
Activity
Go outside with an adult during the day.
Observe the Sun safely.
Notice:
- where it appears in the sky
- the shadows it creates
Later, go outside at night.
Can you find:
- the Moon?
- bright stars?
Draw what you observe.
Practice
Answer these questions.
What planet do we live on?
What gives Earth light and warmth?
Does the Moon make its own light?
Why do we have day and night?
Name the four seasons.
Review
Today you learned:
- Earth is our home planet
- the Sun is a star that provides light and energy
- the Moon reflects sunlight
- Earth rotates to create day and night
- Earth travels around the Sun each year
- people have always been curious about the night sky
Looking up reminds us that our world is part of a much larger universe.
Looking Ahead
Next we will explore maps and our community.
We will learn:
- directions
- neighborhoods
- towns and cities
- maps
- helping our communities
Understanding where we live helps us understand the world around us.