Maddie visits a singing group and the children help us find out how we use our mouths, vocal chords and lungs to make different sounds when we sing and speak. Maddie uses a special machine to measure the different high and low sounds that we make. Next, she visits a trombone factory to see how copper and zinc metals are made into brass trombones. We see how the parts are bent and moulded into different shapes to make the new parts of the trombone and Maddie uses a special gadget to measure the temperature and find out how the metals are heated and stuck together. Show less