Where to look for springs
Did you spring out of bed this morning? Even if you didn't, the chances are that springs got you moving. In fact the springs had been helping you rest all night. They were beneath you in the mattress. We use springs in many different places so let us take a journey through a day and see where we can find them.

After you left your bed you probably went to the bathroom. Many bathroom windows are shaded with a roller blind. If your bathroom window has one, it is pulled down at night to act like a curtain. In the morning you make a brief tug on the bottom of the blind and a spring makes it roll up quickly. In the bathroom there may be scales. Inside this weighing machine is a spring. When you stand on it, the spring is pulled down and this is connected to other parts of the machine, which make your weight appear in a transparent window between your feet. Before you leave the bathroom, you may use some deodorant from a spray can. On the top of the can is a nozzle. When you press down on the nozzle, you push against a spring and a fine mist of pleasantly smelling droplets shoots out. When you let go of the nozzle the spring pushes it upwards and stops the spray from working.

The next room you visit is probably the kitchen. Here you may have to pull on cupboard doors to reach your breakfast cereals. The reason you may have to pull hard is that the door latch has a spring in it, which helps to hold the door shut. When you have had your breakfast cereal, you may put some toast in the toaster. When the slices are resting in the toaster you have to press down a catch to make them go inside. Later, when the slices of bread are toasted, a spring shoots them upward. If the spring is very strong the toast may fly up into the air!

Before you leave home you may tap a barometer. This is a device which hangs on a wall and looks a little like a clock. Inside, the barometer has a metal case and some springs. On the outside is a white dish, with a pointer like the hand of a clock. The air presses on the metal box all the time and sometimes makes the box change its shape. The springs inside the barometer connect the box to the pointer and help it move smoothly to show you what weather to expect.

As you leave your home, you may lock the door. Inside the lock are springs. They hold some pins in place that stop the lock opening on its own. When you put a key in a lock, the uneven edges of the key push the pins out of the way. Each pin has a spring wrapped round it, so when the pin is pushed out of the way the spring is squashed. When the key is in the lock, it can be turned to lock the door then pulled out again. As the key is pulled out, the springs push the pins back into place to hold the lock firmly so the door cannot be opened. When you come home again, you put the key in again and it moves the pins, which squash the springs and you can turn the key the other way to unlock the door.

If you travel to school on a bus you are travelling on a springy machine. There are springs in the engine; springs in the brakes; springs near the wheels to help the bus travel smoothly over an uneven road. There may also be springs in the seats.

Even when you reach school you cannot escape from springs. The first spring you may meet is the one which holds the school door shut. You may have to pull against this spring to get into school. When you are seated ready to work, you may click your pen and a spring inside pushes out the ballpoint end ready for you to write. If you have a project with many papers you may use a stapler to hold them together. Inside the stapler are two springs. As you push down on the stapler you push down on a spring in the handle. Inside the handle a spring pushes on the staples. When a staple has passed through all the papers and folded up to hold them in place, you let go of the top of the stapler and it springs back up. The spring inside pushes the staplers along so the next staple is ready for use.

When you return home it may be dark. If it is, you may use a torch to light your way. Inside the torch is a spring. It pushes on the batteries and holds them together. If it wasn't there, the batteries could move about and the bulb may flicker and go out.

At the end of the day you may pull down that roller blind in the bathroom and when you reach your bedroom you may jump on your bed. If you do, just think of those springs in the mattress that make you bounce and which hold your body comfortably as you sleep.

Where is the spring in a roller blind?
It is inside so you cannot see it. When you pull down the roller blind, you wind up the spring. There is a catch at the end of the spring, which holds the wound-up spring. This stops the spring pulling the blind straight up again. When you give the roller blind a sharp tug, you release the catch and the spring can unwind. As it does so it pulls the blind up and it wraps around the roller.

Do clocks have springs in them?
If you have to wind up a clock it has a spring in it. As the spring unwinds it makes cog wheels inside the clock turn round and moves the hands on the clock face. The wound-up spring is a store of energy which can be used for movement. Other clocks, which do not have a spring, use batteries or mains electricity to move the cogwheels and hands.

Some toys have to be wound up. Do they have springs?
Yes, they do. The wound-up spring is a store of energy, which can be used to make the toy work.

You can make some toy cars move by pushing them a few times on the floor then letting them go. Do they have springs?
No, they have a heavy wheel inside them called a flywheel. When you push the car a few times, you make some cogwheels and the flywheel turn. In fact the flywheel starts to spin fast. When you let go of the toy, the flywheel keeps spinning and makes the car wheels turn so the car shoots off across the floor.

How does a toaster 'know' when to let the toast spring out?
Inside the toaster is a metal bar, which swells and bends as it gets hotter in the toaster. The setting on the side of the toaster makes this bar release a spring after a certain time when the toast is ready. The spring then pushes the toast upwards.

How can the barometer help you tell what the weather is going to be?
The air around us can change the way it presses on things. When the air presses gently there is a good chance that wet windy weather may be on its way. If the air presses more strongly the weather will be dry and still. The metal box in the barometer is very sensitive to the way the air presses. Its sides move in when the air presses hard and move out when the air presses less strongly. The springs in the barometer help the hand move across the barometer face in either direction.

Do the springs in a bus engine work like the spring that makes a toy car go?
No. The energy used to make a bus, car or truck move comes from burning petrol or diesel in the engine. The springs open and close pipes in the engine to control the flow of the fuel and the exhaust gases. A spring would not be powerful enough to move large vehicles.