Maddie is at a building site and finds out how tracks work to help a digger move up and down mounds of earth. Maddie wears some special shoe attachments to show us how the digger’s tracks work to stop it sinking into the soil. Then she attaches a special camera to the digger – to see it in action as it lifts the soil high into the dumper truck! Next, she visits a wellie factory to see how wellies are made. Maddie uses her special cameras to see how the PVC material is injected into the wellie moulds – a bit like making a jelly! We find out how a different colour is injected to make the sole before they are squashed together to make a complete colourful wellie.