In today's episode, Maddie finds out about things that use water. She visits an aquatic centre to show us how a fish tank works, using a special underwater camera to explain how a filter works inside a tank to help keep the water clean and free from fish waste. Next, Maddie visits a factory to find out how bath tubs are made. Starting with a thin sheet of plastic, she shows us how the bath is moulded by air suction. She uses a special camera to explain how a fibreglass gun is used to make the bath strong enough for us to use.