Thinking putty
Model: HL0624-R
Color: Red
Packing: Clear case
Handgum weight: 70g

Thinking putty
Model: HL0624-R
Color: Red
Packing: Clear case
Handgum weight:  70g

Handgum is both a solid and a liquid. Given some time, it behaves like a liquid—it spreads, drips and tends to turn into a flat blob. For example, if you make a ball and put it on the table, in a couple of minutes it will have become a puddle. But if you throw the very same ball against the floor, it will bounce. (Quoted from site)
Hypercolor Thinking Putty is thermochromic -- just a touch from your hands or a warm coffee mug will reveal a new, "hot" color.
Allow it to cool off or, stick it in the fridge! The "cool" color will be restored.
Try painting this Thinking Putty with hot or cold.
Use your microwave with Hypercolor Thinking Putty and verify the speed of light!