Category How does It works, How things work, How is it done, Curiosity

A jet fighter plane is very powerful, but it can’t fly into space. Why not? There is no oxygen in space to power the engine!

All fuel needs oxygen to burn, but a rocket engine does not need air It carries its own supply of oxygen.

Planes get oxygen from the air. But rockets get oxygen from a substance called an oxidizer. Some space rockets use solid fuels with solid oxidizers. They work in the same way as a fireworks rocket-a fireworks rocket as big as a 10 storey building!

Other space rockets use liquid fuels and oxidizers, so that the engines can be switched on or off.

The liquids are pumped into a special part of the rocket called the combustion chamber. Here the fuel burns violently to thrust the rocket upwards further away from the earth.

The Saturn V moon rocket burned over 2,120,000 litres of fuel during its first 105 seconds of flight. This pushed the rocket off the launching pad with a huge amount of force. If you want to get to the moon and back again you have to think big-really big!

Fireworks rockets are displayed at many festivals. Fuel in a fireworks rocket burns like fuel in a rocket engine. In fireworks, the fuel is charcoal and sulphur. The oxygen is supplied by a solid oxidizer called saltpetre. This mixture burns very hot. The gases given off push in all directions against the inside of the rocket. The gases that push against the top of the rocket make the rocket go! The fireworks rocket has a stick that keeps it pointed in the right direction. 

 

Picture Credit : Google

A turbine blade is similar to the blades on an electric fan. The angled blades draw air from behind and pull it forwards. This activity will show you how the angled blades help the turbine spin.

You Will Need:

• scissors
• a piece of cardboard
• a pencil

What to do:

1. Cut a 15-cm circle out of the cardboard. Using a pencil or the point of the scissors, carefully poke a 1/2-cm hole in the centre.

2. Draw a circle around the hole about 1/2 cm outside it.

3. Make 8 slits, evenly spaced around the circle. Cut from the edge to the 1/2-cm mark. Do not cut all the way through. These are the blades.

4. Bend one side of each blade in the same direction.

5. Put the pencil through the hole.

6. Holding each end of the pencil, place the turbine about 20 cm from your body.

7. Blow on the turbine. How fast can you make it spin?

 

Picture Credit : Google

Aeroplanes are usually pushed through the air either by propellers or by jet engines. A propeller looks like two thin, pointed wings joined end to end. As it spins around, it forces air backward. This pushes the aeroplane forward.

The engine of a propeller plane uses the power of burning fuel to turn the propeller. But a jet engine uses burning fuel to make the wheels of a turbine spin. The gases and air from the spinning turbines shoot out from the back of the engine and push the plane forward. An aeroplane with a jet engine can fly much faster than a propeller aeroplane.

Large passenger aeroplanes are usually powered by jet engines. Some jumbo jets can carry more than 400 people. They fly at a speed of 800 to 970 kilometres an hour.

 

Picture Credit : Google

The helicopter pilot starts the engine. Its big blades spin-slowly at first, then faster and faster. But the helicopter is still on the ground. The pilot twists the big blades at an angle. This forces air down. Then the helicopter rises off the ground. The pilot tilts the blades back. The helicopter stops rising and moves forwards. A small propeller at the back of the helicopter keeps it from spinning while the big blades are turning. It also keeps the helicopter from spinning around when it is in the air.

Helicopters are very useful. Since they rise straight into the air, they can land and take off in very small spaces. They can also hover, or stay in one place. So they are often used to help people who are trapped on a mountain, at sea, or on top of a high building.

 

Picture Credit : Google

Submarines are vessels that can travel underwater. They can also float on the surface of the sea and move like any other ship.

Many submarines are powered by a nuclear reactor. The nuclear reactor creates extreme heat used to turn water into steam. The steam drives an engine that turns the propeller. The propeller pushes the submarine through the water.

Tanks on the sides of the submarine are filled with air or water. They allow the submarine to dive under water or surface on the water. Doors, called vents, on the top and bottom of each tank, open and close, letting in water or air.

While the submarine is on the surface, the tanks are filled with air. To dive, the vents are opened.

To make the submarine surface, the bottom vents are opened. The top vents remain shut. Air is pumped into the tanks to blow out the water. When the submarine reaches the surface again, all the vents are shut.

 

Picture Credit : Google

A ship is a big boat Ships are designed to travel the ocean. They usually have several decks, or floors, below the water level.

Some ships, like cruise liners, are out at sea for a long time. They have places for sleeping, eating, working, relaxing, and bathing. A luxury cruise liner even has a hospital, hair salon, shops, and swimming pools.

Most ships are working ships. They are used to carry goods or cargo.

Freighters carry bananas, cotton, coffee, plastics, and cloth. The cargo travels in big metal boxes. Tankers carry bulk cargo, like crude oil or wheat. The cargo is poured right into the hull.

Some fishing ships are like floating factories. They process and freeze the fish on board the ship. Sometimes these ships are at sea for months.

Some Navy ships have large upper decks. Fighter jets land and take off from this deck. Some Navy ships carry researchers, soldiers, tanks, and even helicopters.

 

Picture Credit : Google