The escalator is a set of moving stairs that transports people from one floor to another in a department store, airport, or other public place. Underneath the stairs is a continuous belt that moves around wheels. The stairs are attached to two side belts or to one central belt, which is driven by electricity. The moving handrails on both sides of the escalator work the same way and are timed at the same speed as the steps. At the top and bottom of the escalator, the steps fold flat so they can move underneath the floor, and after traveling around the belt they open up and start again. The same set of steps can be used to run up or down, depending on the direction in which the belt is driven.
- Why are they called skyscrapers?
- How do elevators work?
- What is the tallest building in the world?
- How is steel used in skyscrapers?
- What is the Nobel Prize?
- Why are there different religions and how did they spread?
- What was the Industrial Revolution?
- What is a patent?
- What is the difference between an invention and a discovery?
- Which state was once an independent kingdom?
- Where can you stand in four states at the same time?
- Which state has the most people?
- Which is the largest state in area, and which is the smallest?
- How can you travel across Alaska’s miles of snow?
- Why do states have names and nicknames?
- Is the District of Columbia a state?
- Why do women in some countries wear veils?
- Which states were not organized as territories first?
- How did the United States begin?
- How did we get the United States national anthem?
