Our Solar System: How Big? How Far?

What We Will Do

We will learn about the solar system.

The solar system has the Sun. It has planets too.

We will make a model. A model helps us understand things.

We will use string and beads. Beads will stand for planets.

We will also use fruit. Fruit will show how big planets are.

Words to Know

Planet - a round thing that moves around a star.

Solar System - the Sun and everything that moves around it. This means planets, moons, and more.

Scale - using small things to show big things.

Prediction - a smart guess about what will happen.

Model - something that helps us understand a real thing.

Step 1: Make a Guess

Think about a trip to every planet.

First, guess how far each planet is from Earth.

Draw the planets. Draw the Sun too. Show how far apart you think they are.

Remember all the planets. Remember their order too.

Here is something fun to think about.

A car ride to the Sun would take 163 years!

A car ride to Mars would take 81 years!

A car ride to Pluto would take 6,357 years!

Rockets go much faster than cars. But this helps us think about distance.

Step 2: Find the Real Scale

Now let's find the real answer.

We will measure string. We will cut it 4.5 meters long.

We will use colors for each planet.

• Yellow bead is the Sun
• Red bead is Mercury
• Cream bead is Venus
• Blue bead is Earth
• Red bead is Mars
• Black bead is the Asteroid Belt
• Orange bead is Jupiter
• Gold bead is Saturn
• Dark blue bead is Uranus
• Light blue bead is Neptune
• Brown bead is Pluto

We will tie each bead on the string. We will tie it at the right spot.

This shows the real distance between planets!

Step 3: Talk About It

Let's talk about our guesses.

Were they close? Were they far off?

We will learn why the real distances are so big.

Step 4: Guess Planet Sizes

Now let's think about size.

We will look at fruit and seeds.

We will guess which fruit matches each planet's size.

Some fruits we might use:

• Honeydew melon
• Cantaloupe
• Lemon
• Lime
• Grapes
• A macadamia nut
• Peppercorns

We will guess first. Then we will check our answers.

Step 5: What Did We Learn?

Let's think about our first guesses.

Let's think about what we know now.

Scientists don't know everything at first.

Scientists make guesses. Then they test their guesses.

Scientists use models to learn new things.

You can be a scientist too!

A Fun Question

Did you know Pluto is not called a planet anymore?

Our solar system used to have 9 planets. Now it has 8.

Why did this change?

Scientists group things by how they are alike.

Long ago, we did not have strong telescopes or spacecraft.

We did not know as much as we know now.