Elastic materials are useful in lots of ways: Similar to how tires and sneakers grip the road, a rubber band can help you grip the lid of a jar to make it easier to open. Your body’s cartilage is your ...

We call these materials elastic, like rubber bands. You can change the shape of some materials like Plasticine. You can push it. Pull it. Bend it. Stretch it. And when you do it stays that shape ...