Continuing on our theme of atmospheric pressure, this week we experiment on increasing and decreasing pressure, and how it affects the air trapped inside of marshmallows.
A plastic bag is connected to a vacuum pump. Initially the air inside the bag pushes out with the same force as the air outside of the bag pushing in. However, when the air is pumped out of the bag there is nothing to counteract the atmosphere squeezing the bag against the bear.
Last time we saw that we can separate mixtures by using size and magnetism. This time we use density to separate a mixture. This process is used to separate different types of plastics so that they can be recycled.
River sand is a mixture: it’s a combination of many types and sizes of materials that are combined together without being chemically bonded to each other. Mixtures can be unmixed, or separated into component parts using various physics techniques.