There are many items that make our everyday lives easier. Have you thought about how they work?
Escalators are great. They can take us to different floors. You can see them in almost every shopping centre and airport. An escalator has many steps, and they are all attached in one giant loop. A motor powers the loop. The motor keeps turning the loop of steps; that's why we never run out of steps. It keeps the escalator moving. The same motor also moves the handrail.
Elevators can take us up and down different floors too. We are able to go up to the 50th floor very quickly. But how do they work? Elevators that have to go up more than 4 floors are traction elevators. Inside the elevator shaft, the elevator is attached to cables. The cables run over the pulley at the top of the shaft and down to a counterweight. The gravity force on the counterweight balances the gravity force of the elevator. That's how an elevator goes up and down a building.
Do you have a printer at home? There are two main kinds of printers. Inkjet printers use a printhead that has many tiny holes at the end. As the paper goes through the printer, miniscule ink droplets come out of these holes. This happens really quickly. Thousands of these droplets come together to form an image or text. We can't actually see all these little droplets, because they are too tiny for our eyes. We can only see the content we wanted to print out.
Laser printers are also commonly used. Like the inkjet printer, the laser printer uses tiny dots to form images and text. But laser printers do not use liquid ink; instead they use toners. Printing is much more complex on the laser printer. The laser printer has a drum and a laser. The laser recreates our images by drawing on the drum. An ink roller touches the drum and coats it with toner. The toner sticks to the drum. When a piece of paper goes through the printer, the toner is transferred to the page. Then the page goes through two hot rollers that will fuse the toner in place.
It is the law in many places to have sprinklers inside buildings. Look around: do you see sprinklers on the ceiling? They are there in case of a fire. Many people think that sprinklers detect smoke. This is not true. Sprinklers are actually triggered by heat. There is a liquid inside each fire sprinkler. This liquid expands once it reaches a certain temperature. When a room gets too hot because of a fire, the liquid will burst out of its container. This will open the way for water to flow out of the sprinkler head.
Binoculars can be very useful when you need to see something far away. They work because of the way light travels through prisms. Light bounces through the prisms inside the binoculars. As it comes out through the lens where your eyes are, the image is magnified. That is why we can see things much larger than they really are.