In today's episode, Maddie is at home to show us how a refrigerator works. She explains how the pump and the long pipes inside a fridge change a cooling liquid into a gas to help the food inside stay cold. Using a special thermal camera we see how food cools down inside. Next, Maddie heads to a mushroom farm to see how mushrooms are grown in a big factory. We see how the climate is controlled by a computer so the mushrooms can grow indoors all year round. Maddie uses a special camera to show us the microscopic spores that grow into mushrooms.