This activity will give your son or daughter a sense of how big different objects in the solar system are in relation to each other and how far they are from the sun.
If the sun was the size of a basketball, how big would the planets be? To answer this question, your student will need:
- 1 basketball (this represents the sun)
- 2 pins (the heads of these pins represent Mercury and Mars)
- 2 peppercorns (these represent Earth and Venus)
- 2 peanuts about 0.3” diameter (these represent Uranus and Neptune)
- 1 pecan about 0.9” diameter (this represents Jupiter)
- 1 acorn about 0.7” diameter (this represents Saturn)
Start by lining up the objects in order on a table: Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Note the relative sizes of these objects.
If the sun was the size of a basketball, how far would the planets be from it? Find a long straight road in your town—at least half a mile long (preferably one with a sidewalk for your safety). Set the basketball down at one end. Get a measuring tape and measure from the ball…
- Place Mercury (one of the pins) 33’ from the ball
- Place Venus (one of the peppercorns) 62’ from the ball
- Place Earth (one of the peppercorns) 85.5’ from the ball
- Place Mars (one of the pins) 130’ from the ball
- Place Jupiter (the pecan) 445’ from the ball
- Place Saturn (the acorn) 819’ from the ball
- Place Uranus (one of the peanuts) 1644’ (about 0.3 miles) from the ball
- Place Neptune (one of the peanuts) 2,572’ (about 0.5 miles) from the ball
In this model every inch represents about 90,569 miles.
If the sun was the size a basketball, how close would the closest star be (Proxima Centauri)? We can measure this easily in feet because you would have to travel 4,343 miles. That’s over half the diameter of the Earth.
Learn More About the Planets!
If your child is 12 years old or older, they will love Experience Astronomy, a full-school-year online course. Not only do students learn about the planets and other objects in our solar system, but they also learn how to read the sky like a map, identifying major constellations, moon phases, and all the various motions of the sky above.