Experimenters Brodie, Callum and Maykl visit Nina in her lab and discover that the bubbles in fizzy drinks are made of a type of gas. Nina explains that when people drink fizzy drinks, or just eat or drink too quickly, gas can build up in their tummies, so they burp to get rid of it!

Next they visit a lighthouse to hear how a gas, like air, can make a loud noise when it is pushed though a foghorn. Back in the lab, they do a noisy experiment with balloons and discover that the burping noise is made when gas from people's tummies pushes past a muscle at the top of the food tube, making it wobble. Nina reminds everyone that burping can be rude. Show less