Nina investigates how broken bones get better, with the help of Felix, her touch neuron. Experimenters Cei and Jack discover that bones are really hard and strong because of something called calcium, which is in lots of yummy foods. But bones can sometimes break if someone has an accident. Nina takes the Experimenters to a hospital where a doctor shows them some x-rays of broken bones. They discover that a break in a bone is called a fracture.
Back in the lab, they discover that the body sticks broken bones back together with a special substance that is a bit like glue. But it is really important that the broken bone cannot break apart again while it is growing back together. So a hard cast is placed around the broken bone while it heals. Nina and the Experimenters have fun sticking some pretend broken bones back together and make casts to hold them still.
