Scale of the Solar System

Lab Brief #10

🎯 Your mission

Run the experiment. Find out what really happens.

⚡ The twist

The light you see now started its trip a long time ago.

What you'll learn

Planet diagrams almost never show true distances. If the Sun were a football, Earth would be a peppercorn about 26 metres away and Neptune would be nearly 800 metres off. Space is mostly empty, and diagrams that fit on a page hide that.

Key words

astronomical unit
The average Earth-Sun distance, about 150 million kilometres.
scale model
A model in which all distances are reduced by the same factor.

Make a hypothesis first

Guess: how big does that look from here vs. from there?

Say your guess out loud — then find out if you were right.

Get ready

🧰 What you need

football
peppercorns and beads
long tape measure
open space

⚠️ Safety first

Small beads and peppercorns are a choking hazard — keep them away from young children.
Go outdoors with an adult and stay clear of roads.

Step 1 of 4 · Read

Think about what you just learned: say what "astronomical unit" and "scale model" mean in your own words before you start.

Step 2 of 4 · Do

Build a walking-scale solar system on a field or long corridor with the Sun as a football. Pace out each planet's distance to scale and photograph the line, then explain why textbook diagrams cannot do this.

Step 3 of 4 · Observe

Record what actually happened, including anything that did not match what you expected.

Step 4 of 4 · Record

Write a conclusion that answers the question this lesson opened with, and state your uncertainty.

Question 1 of 2

One astronomical unit is roughly:

How sure are you?😐 maybe

Question 2 of 2

Textbook solar system diagrams are misleading mainly about:

How sure are you?😐 maybe

Mind = blown

🪐 A day on Venus is longer than a year on Venus.

Nice work!

You got 0 of 2 right.

Next: Why We Always See the Same Face of the Moon All lessons

🎯

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✨ More to explore

🌍 Where you see this in real life: GPS, weather forecasts, and the seasons all rely on this.

🏆 Stretch challenge (try it this week): Find a constellation in the sky. Look it up. Tell someone its story.

👨‍👩‍👧 For the dinner table: “If you could visit any planet, which would you pick and why?”

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