A true classic of planetary projects: the model solar system. One fun variation of this is to make a model fit onto a yardstick. Use a scale of 1 inch for 10 million miles. Starting at one end, attach an orange (or a Styrofoam ball) that represents the Sun. Attach Mercury about 3.6 inches away. Take the average distance from the Sun for the other planets and dangle them from the yardstick. Make the planet sizes accurate.
When studying the relative weight and densities of the planets it can be somewhat confusing to learn that Jupiter, though roughly 300 times the weight of Earth, is actually less dense than our planet. To demonstrate this and learn more about it, take two deflated beach balls and weigh them while empty. Cut a large slit in the side of each ball. Then, fill them with different things such as water, dirt, shredded paper or socks and seal the slit with packaging tape. Record how the different densities affected the overall weight of the beach balls.
For this project, you will need a shoebox, flashlight, pin, pencils, tape and a star chart or constellation map. Cut a hole in one end of the shoebox so that the flashlight can fit snugly inside. On the other side of the shoebox, cut a rectangle roughly the size of the paper you're using. On the paper, trace the maps of different constellations, and poke tiny holes in the paper with a safety pin where the stars are located. Do this for as many constellations as you like. Tape the paper over the rectangle you cut, turn off the lights, turn on the flashlight and enjoy viewing the constellations from the comfort of your living room.
You can make your own Martian soil right at home. You'll need sand, a large glass bowl, iron fillings or steel wool, scissors and water. Fill the bowl with sand so that the bottom is completely covered. Cut pieces of steel wool and mix them in with the sand. Cover the sand with water and check it every day. If the sand gets dry, add more water so that the sand is always damp. As the water evaporates, there is a chemical reaction between the oxygen in water and the iron in the steel wool that causes the sand to turn red in color. This rusty soil is similar to what scientists believe the soil is like on Mars.
Building a simple telescope is a fun, easy way to see the stars more clearly at night. You'll need two lenses with different focal points -- these can be obtained from taking the lenses from different powered magnifying glasses -- a paper towel roll, tape and card stock.
Roll the card stock into a long tube about the diameter of the lens with the shorter focal point. Secure the rolled up card stock with tape or a glue stick, and tape the lens to the end of the card stock tube to make an eyepiece. Take the other lens and tape it to one end of the paper towel roll. Now you can insert the tube of card stock into the paper towel roll, look through your eyepiece, adjust the focus by sliding the eyepiece in or out of the paper towel roll, and experience the stars through your homemade telescope.