Foam glass

Foam glass is a type of lightweight material that is made from glass and air. It's made by heating glass until it changes into a foam-like structure with lots of tiny air bubbles in it. Foam glass is very light, so it can be used to make things like insulation for buildings, which helps to keep homes and other buildings warm in the winter and cool in the summer. Foam glass also has great sound-proofing abilities and can be used to block sound from entering a building from outside. It is also fire-resistant and water-resistant, making it a great material for many different projects.