Distances between planets are hard to conceive, especially since most graphic representations of our solar system show the planets much closer together than they really are. Depending on the space you have available, you may want to change your scale--with a millimeter or a centimeter representing 1 million km. If you use centimeters, starting at the Sun, that would put Mercury at 58, Venus at 108, Earth at 150, Mars at 228, asteroid belt at 400, Jupiter at 778, Saturn at 1427, Uranus at 2871, Neptune at 4497, and Pluto at 5914. Keep in mind that 5,914 centimeters is 59 meters, or 64.5 yards, and putting the Sun and Pluto only six and a half yards apart might be more practical for indoors.
Because the difference in size between the Sun and Pluto is so great, the best scale to use is 5 mm for every 1,000 km of diameter. That would make the Sun around 70 cm and Pluto only 1.1 cm. The other diameters (in cm) would be Jupiter (71.5), Saturn (60), Uranus (25.5), Neptune (25), Earth (6.3), Venus (6), Mars (3.5) and Mercury (2.5). Keep in mind that the scale is greatly different from the previous demonstration, so it is not realistic to set up a model using both demonstrations together.
Because gravity is based on the mass of the planet you are on, you can calculate your weights on the moon and the other planets. Mass is not always related to diameter; for example, Jupiter is very large, but not as dense as a planet like Earth or Venus, so the difference in gravity may be less than the difference in diameter. To calculate weight on other bodies, multiply the weight by the following numbers: Pluto (0.07), Moon (0.17), Mars or Mercury (0.38), Uranus (0.89), Venus (0.9), Saturn (0.92), Neptune (1.13), and Jupiter (2.36).