Cut out a circle from a large cardboard container or a large roll of butcher's paper. The diameter should be 150 centimeters, which is about 6 feet. Use a compass and a pen or colored marker to draw eight circles around the center. The first circle should have a diameter of about 1.5 centimeters. The second circle should have a diameter of 3 centimeters. The third circle's diameter is a little less than 4 centimeters. The fourth circle should have a diameter of 6 centimeters. Draw the the remaining four circles using string to measure the diameters, which will be 20, 40, 80 and 120 centimeters.
Label the circles with a pen using the names of planets. These circles represent the orbital distances of the eight planets. The first orbit belongs to Mercury. The second is for Venus. Earth comes third. The remaining five orbits, in order, are Mars, Jupiter, Saturn, Uranus and Neptune. Stagger these labels around the circles so that they are not in a line.
Cut out representations of the planets and the Sun from pieces of colored construction paper. Do not make the Sun any bigger than one centimeter in diameter. The planets should all be smaller. The choices of colors are up to you, but bright yellow for the Sun and blue for the Earth will make it easy for people seeing the model for the first time to acquire reference points. You may wish to add color to some of the circles, such as Jupiter or Saturn, to represent their striped appearance.
In order to keep the inner four planets form jostling one another, glue them on the solar system model at staggered points on their orbits, near the written label for their names. Do the same with the outer four planets.
Dot the entire circumference of the open space between Mars and Jupiter with a dark marker. Write in the word "Asteroids" here.
Create a scale at the bottom right of the cutout. Draw a line that is 1 centimeter in length. Put an equal sign next to it and write "75 million kilometers."