Imagine having to walk or run everywhere, instead of travelling in a car, train or plane. Isn’t science supposed to make things easier for use?
An engine, or motor, is a machine used to change energy into movement that can be used. The energy can be in any form. Common forms of energy used in engines are electricity, chemical (such as petrol or diesel) or heat. When a chemical is used to produce energy it is known as fuel.
An engine (or motor) is a basically machine that converts energy (electricity, chemical – petrol/diesel, heat, etc.) into some sort of movement. Engine creates mechanical energy from heat, whereas motor creates mechanical energy from other kinds of energy, such as electricity.
- Examples of engines: Steam engine, internal combustion engine
- Examples of motors: Electric motor, hydraulic motor
Most cars today have petrol engines. A mixture air and petrol is pushed into a hollow chamber called the cylinder. A spark from a spark plug makes it explode, which pushes a piston down inside the cylinder.This movement is used by gears to turn the wheels. Most cars have four or six cylinders.
A diesel engine also works in a similar way, but without using sparks. The mixture of air and diesel is squashed so much in the cylinder that it becomes hot enough to explode. Diesel engines are usually used where lots of power is needed, in trucks, tractors and big trains.
A Jet engine mixes air and kerosene and sets fire to it in one long, continuous, roaring explosion. Extremely hot gases blast out of the back of the engine. These push the engine forward – along with the plane.
An electric motor passes electricity through coils of wire. This makes the coils magnetic, and they push against magnets around them. The push-pull makes the coils spin on their shaft (axle).
Engines which burn fuel give out gases and particles through their exhausts.
Some of these gases are harmful to the environment. The less we use engines, the better. Electric motors are quiet, efficient and reliable, but they still need fuel – to make the electricity at the power station.
What type of engine is found in these vehicles. Is it a jet engine, electric motor, petrol engine or diesel engine? Let’s see if you know the answers.
1. Cable Car – Electric motor
2. Formula 1 racing car – Petrol engine
3. Fork-lift truck – Diesel engine
4. Aeroplane – Jet engine
Engines are machines that use fuel to do work for us and make life easier. Fuel is a substance that has chemical energy stored inside it.The energy is released as heat by burning or exploding the fuel in the engine.
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