Elevators and escalators can be fascinating for kids. These mysterious mechanisms make going from one floor to another in a building an exciting trip that is almost as much fun as a ride at an amusement park. Kids also like to know how things work. These fascinating machines actually feature relatively simple construction, relying primarily on mechanical operations, although computerized buttons and controls have been added to many modern elevators to make them work better.
Escalators are really just big conveyor belts that move people. To demonstrate how a conveyor belt works, position two straight-backed wooden chairs with their backs toward each other. Slip a piece of wire through a spool for thread, and fasten it to the back of one chair, and repeat with another spool on the other chair. Loop a wide ribbon over both the spools, and tape or staple it, so that it makes a taut continuous loop over the spools. Place a penny or other small object on the ribbon and show your child how to pull on the bottom part of the loop to make the top move from one chair to the other.
Explain that a belt like this makes the steps on an escalator move, but that escalators have gears and guides under the steps to make them stay level, so people won't fall off. However, because it is a big conveyor belt, some safety precautions need to be taken. No wheeled things, like strollers, on the escalator. Step on quickly, and remain standing up during the ride. Keep skirts and other loose clothing close to your body.
On the other hand, an elevator is a big box or platform that can carry people and things up and down. There are two basic kinds of elevators, named for the way the box is moved. One is a hydraulic elevator, and the other is a rope-lifted elevator. The hydraulic elevator works like a hydraulic car jack, while the rope-lifted elevator works like an old-fashioned window sash that has ropes, pulleys and counterweights to make it easy to move up and down.
You can use a hydraulic car jack to explain a hydraulic elevator. If you don't have one of your own, you might be able to visit an auto supply store to look at one. Show your child how the hydraulic jack is made up of cylinders that fit inside each other. Explain that when you operate the pump handle, fluid pushes the jack up. When the jack needs to go down, you release the fluid and it flows back down.
To demonstrate how a rope or cable elevator works, start by showing your child that if you fasten a rope or string to a box, you can use the string to lift it. Thread a piece of wire through a sewing thread spool, and suspend the spool from the top of a door or other high place to which you can fasten it. Thread the string over the spool, and explain that pulleys help lift things. Finally, tie a counterweight to the other end of the elevator string. A spoon or other object that equals the weight of your elevator box will work. Show your child how a slight tug on one or the other will send either the weight or the box to the top of your elevator space.
Also, explain that real elevators have motors to pump the hydraulics or to help turn the pulley to make the elevator go up or down. The elevator has a lot of safety devices built in it to make sure that even if the motor stops working, the elevator won't fall.
One of the safety features found in most elevators is a set of brakes that push out against the sides of the shaft to make the elevator box stay in place until a repairman can come fix any problems. Cable or rope elevators have at least four different sets of pulleys, so that if one should break, the others will continue to hold up the elevator. Even though most elevator doors will stop closing if part of your body crosses the threshold, never assume that this is the case. Be prepared to pull back if the door continues to close.