Astronomy is a subject that often fascinates students of every age. The solar system is very spread out, which makes accurate scale models difficult to draw. Planets such as Jupiter are 1/10 the size of the sun, but Earth is 1/100 the size of the sun. With the right materials it is possible to draw a fairly accurate scale model of the solar system.
Choose between using either a large circular piece of cardboard, or a very large sheet of paper from an artist's sketch pad. The circular piece of cardboard can be helpful because the sun will be the center and the planets' orbits are easier to draw, but finding a piece large enough can be a problem. Cutting a circle from the side of an unwanted refrigerator box could be a good method. Most find it easier to find the largest sheet of paper available from a sketch pad and to work from there.
Measure out the entire length of the page in either millimeters or centimeters. Most of the time millimeters will be the better option because of how spread out the solar system is. It is easier to scale in millimeters than centimeters most of the time. You will need to know the total length in millimeters because this will help you determine the scale you're going to use.
Examine the real distances between planets and the sun to figure out what your scale should be. This will vary based on the length of your paper or cardboard cut out. The best way to get a quick rough estimate is to look up the distance between the furthest planet you're going to chart and the sun (for Neptune, it's 2.27 billion miles or 4.45 billion kilometers). Take that number and divide it into the number of millimeters you have to work with on your cardboard or paper. Give yourself a little bit of extra space and that will give you an idea of your scale.
Draw the sun in the exact middle of the page, sketching lightly with a pencil. Use a ruler or measuring tape and your scale to figure out how far away each planet should be. Put a little dot on both sides of the sun, then use a compass to draw the orbit by connecting the dots. Repeat this step for all eight planets (or nine if Pluto is still counted).
Rsearch the relative size of each planet to make an appropriate-sized dot. Earth is only 1/100 the size of the sun, but Jupiter is 1/10 the size of the sun. In a scale model then the sun should be 10 times the size of Jupiter, while Jupiter should be 10 times the size of Earth. Because the scale measures distance as opposed to radius, you can get away with fudging the sizes a little, just remember that the relative sizes should just about match.
Draw a different color for each individual planet with marker. Remember that with the orbits marked on the page, the planets don't all have to be lined up behind one another: in fact, in real life they never are.
Use pencil to trace. You may find after the first time that you need to redo the scale and measurements.
Have more than one piece of paper or cardboard handy in case you make a mistake. The scale can be hard to get down the first time.