A mass structure is a natural or man-made structure formed by stacking together materials. Pyramids, igloos, and beaver dams are examples of mass constructions. A mass construction has greater strength than its individual components because they work together to absorb force away from poorly supported parts of the structure. Mass structures can be used for defense purposes or as simple dwellings. For example, if you were to build a house out of mud bricks that is not protected by anything else, it would be very easy for someone to destroy with a fire. But if you built your house out of concrete instead, it could protect itself against heat damage or smoke damage from a fire. In science class, we use mass structures in experiments to determine how things affect each other when they interact through gravity. For example, we might drop weights from different heights to see how the weight affects the object it falls on. Or we might pour liquids into identical jars to see which one floats up highest. These are all examples of experiments that use mass structures. In math class, we use mass structures to represent quantities. For example, we might express the number 100 as 1 hundredth of a pound, 10 kilos, or 2 tonnes. We can also use mass structures to show how much more/less than a certain amount there is of something.