Want to get your kinds interested in astronomy at a very young age, then build them a Solar System mobile. Imagine all of the planets hanging from the ceiling at their approximate orbits, for your children to study and enjoy.
Before you get started, though, you need to make a few decisions. First, how much do you want your mobile to reflect reality? Just to give you an example, if you tried to build a scale model of the Solar System, you could cut a large Sun out of a piece of printer paper, and then put the other planets at the right distances away from it. If you did it to scale, Pluto would be the size of the head of a pin, and be located about a kilometer away.
If you are interested in doing that project, here’s a full article with all the instructions you need to build a scale model of the Solar System.
But let’s assume that you want something you can hang in your children’s bedroom. Do you want something small that just hangs in a corner, or do you want to fill the whole ceiling with planets – especially if there’s a light in the middle that you can use as the Sun.
If you’ve got some room, you can make the sizes relatively correct.
First, let’s do the orbits. The planets in the Solar System go like this: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune. Pluto isn’t a planet any more, but you’ll probably want to include it too. You can also include some asteroids in between Mars and Jupiter.
Now consider the sizes. You can go down a craft store and purchase foam balls of different sizes. Mercury, Mars and Pluto should be the smallest balls. Earth and Venus should be the next larger size. Then Uranus and Neptune are larger balls. And finally, Jupiter and Saturn should be the largest ones.
In the real world, Jupiter is 11 times larger than Earth, and Mars is about half the size of Earth. It’s unlikely that you’ll want to have planets with that different a size, but try to show the differences.
Paint the planets to match how they look in the real Solar System. Here is a link to NASA’s Planetary Photojournal. It gives you photographs of all the planets in the Solar System, which you can use as a guide. In general, Mercury is grey, Venus is brownish yellow, Earth is blue, green, brown and white, Mars is red, Jupiter is yellow/brown with lighter and darker stripes, Saturn is more yellow, Uranus and Neptune are blue, and Pluto is light grey.
Then hang them up from the ceiling, and enjoy the oohs and ahhs, and get ready for a million questions about the Solar System.
We have recorded a whole series of podcasts about the Solar System at Astronomy Cast. Check them out here.