Produced by Thames & Kosmos. $9.95 www.thamesandkosmos.com

Make five colorful, rubbery balls resembling planets in minutes. This kit includes a spherical mold and five colors of polymer granules (red, orange, yellow, blue, and purple) to safely cast up to five planet models. Kids can explore the scientific properties of polymer materials as they learn why the balls form and how the elasticity of the material causes them to bounce. The kit comes with packaging and manuals in English, French, and Spanish. For ages 8 and up.