Category Great Discoveries, Invensions

With a hairdryer, we don’t have to wait for our hair to dry.

Inside the hairdryer, electricity travels on a pathway of wire. The electricity travels easily on most of the wire in the pathway. This is called conducting electricity. The path is open. The electrons in the wire are free to move.

But some metals resist, or slow down, the electric current flowing through the hairdryer. When the electrons slow down, they bump into one another as they move through the wire.

Then the wire heats up. The harder they bump and push, the hotter the wire gets.

When you plug in a hairdryer and turn it on, electricity travels through it. It powers a tiny fan. Then the electricity travels to coiled wire made of resistant metals. These wires heat up. The fan blows heat from these wires out through a vent. This is the hot air that dries your hair.

Inside an electric hairdryer, there is a coil of wire that heats up. The fan blows the heat out to dry your hair.

Picture Credit : Google

Brrrrahhhh! It may sound like a roaring monster, but it’s only a vacuum cleaner doing its dirty work. The noise comes from an electric motor that runs a fan. The fan helps the vacuum cleaner suck the dirt up the hose and into the bag.

When you turn on the vacuum cleaner, the fan starts. It draws air from the bottom of the vacuum cleaner up into the dust bin or bag. As the air moves up, it leaves an empty space at the bottom of the vacuum cleaner. Any empty space is called a vacuum. That’s how the vacuum cleaner got its name.

A brush at the bottom of the cleaner helps loosen dirt in the rug. This brush is called a beater brush. A rubber belt connects the brush to the motor. As the motor spins, the brush spins and makes the rug vibrate. The vibration loosens the dirt. The vacuum pulls more air and dirt into the dust bin or bag.

When the dust bin gets full, it needs to be emptied. Or, when the bag gets full, it needs to be thrown away and replaced with a fresh bag.

Picture Credit : Google

Are your favourite jeans dirty? No problem. Put them in the washer. They’ll be clean and ready to wear in no time. When people washed clothes by hand, it took all day. After the clothes were washed, each item had to be twisted to wring out the water.

Today, a washing machine does all the work. First you choose the wash setting. Then you add your clothes and detergent. When you turn the machine on, the machine fills the washing basket, or drum, with water. A tiny computer chip, called a sensor shuts off the waterflow when the level is high enough.

The clothes twist or tumble about in the soapy water. When the clothes are clean, a pump drains the dirty water from the machine. Then the rinse cycle fills the drum with clean water. When the rinse water is pumped out, the timer switches the motor to a faster speed, and the drum spins very quickly. The clothes are flung against the sides of the drum. The water is forced out of the clothes and pumped down the drain. Now your clothes are ready to be tumble dried.

Picture Credit : Google

Toast is tasty for breakfast or a snack. And with a toaster, it’s so easy to make.

First, you put a slice of bread in each toaster slot. A rack holds it in place. Then you push down the lever. The lever is connected to the rack and to a spring. The spring unwinds, but a hook holds the rack down. The heat turns on. The coils inside each slot glow orange.

The heat from the coils toasts the bread. It also heats a metal switch. The switch is made from two types of metal. One type expands from the heat. The other does not. As one half of the metal expands, the switch bends. When it bends, it moves a small bar. This bar pushes against the hook. The rack is released. The spring makes the rack and the toast pop up!

Picture Credit : Google

Are you hot or cold? A thermometer will take your temperature. There are many different kinds used for different purposes. Take your pick.

One type of thermometer has a thin glass tube partly filled with liquid. When the air is warm, the liquid in the tube becomes warm and rises. It rises because heat makes a liquid expand, or take up more space. The warmer it gets, the more space it needs. When the temperature drops, the liquid contracts, or takes up less space, so it moves down the tube. The liquid in many thermometers is a silver-coloured metal called mercury. Some thermometers are filled with coloured alcohol.

A digital thermometer has a metal probe. When the thermometer is turned on, a battery inside sends around an electric current. If the probe is warm, the current will move easily. If the probe is cool, the current will not move as easily. The thermometer shows a temperature reading based on how easily the current moves.

Doctors often use an IR thermometer to detect infrared rays from a person’s eardrum. The hotter you are, the more radiation the thermometer detects. The thermometer converts the amount of radiation to a temperature reading.

 Standard thermometer contains a liquid that moves up when it becomes warm. The liquid drops down when it cools. The lines indicate the temperature.

The lines and numbers on the thermometer indicate degrees. They tell you how much the temperature changed. Degrees are marked with the symbol º. The number 0 ºC is the temperature at which water freezes. This is the same temperature as 32 ºF. The letter C stands for Celsius, and the letter F stands for Fahrenheit.

Picture Credit : Google