Building a solar system model is an ideal project for a science fair or school assignment. Using simple foam balls from a craft store and some paint for embellishing, you can quickly put together a solar system model that, while not representing the relative size of the planets or the exact scale of the solar system, gives an approximate idea of the position of each planet in relation to the others. The vast space between each planet makes it difficult and impractical to show the exact distance between planets.
Purchase nine foam balls from a craft store to represent the eight planets of the solar system and the sun. You will need one 5-inch ball for the sun, two 4-inch balls for Jupiter and Saturn, two 3-inch balls for Uranus and Neptune, two 2-inch balls for Venus and Earth and two 1-inch balls for Mercury and Mars.
Paint each foam ball according to the colours of that planet. Paint the sun yellow; Mercury, Mars and Jupiter brown; Venus, Earth, Uranus and Neptune blue; and Saturn red. Let dry.
Cut eight pieces of craft wire about five inches long to make the rings of Saturn. Wrap each wire piece around the Saturn ball and stick the ends of each wire into the foam ball to secure.
Paint the inside of a cardboard box black to symbolise space. Let dry.
Cut nine pieces of craft wire to about six inches long. Stick one wire into the centre of each foam ball.
Insert the sun foam ball into the centre of the box by sticking the open end of its wire through the cardboard in the box. Insert Mercury, Venus, Earth and Mars next, each one about one inch apart, in a circle pattern around the sun as if they are in orbit. Leave about three inches from Mars, then insert Jupiter, Saturn, Uranus and Neptune each about one inch apart, continuing the circle pattern.
Decorate the cardboard box with star stickers.