Here are the joints in my arm! Kinda like the joints you see in this skyscraper!
The bones in our body--our skeletons--hook together with joints. Our knees, elbows, hips, and wrists are all JOINTS in our body. Even our fingers have little tiny joints.
The steel beams of a skyscraper hook together with joints also. Sometimes they are even called joints. But more properly, they are called CONNECTIONS. The connections are fastened with bolts or rivets, or they are welded together. Welding is a process where metal is heated so hot that it turns into a liquid--like a candle--and placed on two pieces of metal. When the molten metal cools, it hardens and keeps the two pieces locked tight together.
Most people think that skyscrapers are always built really stiff, so that they can stand still in bad windstorms like tornadoes and hurricanes. This isn't always true. In some areas of the country, especially where they have earthquakes and hurricanes, the connections are made so that they can act more like the joints in our body. They are made to BEND and move when they need to.
Click on Tom's right arm to see his joint!