Invertebrates have their skeleton outside their bodies. This exoskeleton protects the animal like a suit of armour. However, it does not grow with the animal so it must produce a new one as it gets bigger, rather like a new set of clothes. A bronze bug has grown out of its old skeleton, so it wriggles out and waits for its new skeleton to harden in the sun.

First broadcast:
8 October 2007

Could be used within the subject 'Life processes and living things'. First show the clip, then demonstrate the outside skeleton with the help of jelly. Bring in a tub of jelly and let the children comment on the consistency. How easy is it to break up the jelly? Put a container over the jelly and ask the children if the jelly is safe now. What makes the jelly safe? Perhaps stop the clip at the first image to explain which types of animals are invertebrates. Ask the children to name them and then come up with other ones. Maybe try to bring in an empty exoskeleton and let the children explore it.