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An easy way for kids to model solar-system objects and get their densities right!

If the Earth were the size of a basket ball (24 cm) then the Moon would be 6.5 cm across. This girl (who is six) and her class mates followed a recipe and made a model of the Moon out of Playdough mixed with steel nuts. It was not only the right size, but the right density too. This way she can really feel the scale of the solar system.

Playdough Planets is a spreadsheet that helps kids and their teachers to make models of planets and moons and allows them to explore the solar system by comparing diameters, distances, angular sizes, areas, gravity and other properties.

By making the models from mixtures of different materials, we can make the density of the models the same as the average density of the actual planet or moon. All the kids have to do to make models of the correct size, is collect the right amount of stuff and then form it into a ball.

Older children can experiment with the speadsheet directly - trying out different values and adding their own objects. Younger children can simply follow the 'recipes' printed off by a teacher.

Did you know... If you can jump 30cm high on Earth, you could jump over 753 metres high on Deimos (the smaller of the two moons of Mars). Jumping 30cm takes half a second on Earth. The equivalent jump would take nearly 21 minutes on Deimos! This comparison has been brought to you courtesy of the (Interactive) Gravity Worksheet.

Download Spreadsheet (1MB)

Screenshot: Sizes Worksheet

Screenshot: Sizes Worksheet

Screenshot: Distances

Screenshot: Areas Worksheet

Screenshot: Gravity

Download Playdough Planets: (1MB)

(Documentation, inclduding an explanation of the calculations, can be found in the About Playdough Planets worksheet within the spreadsheet.)

This work is licenced under a Creative Commons Licence.