Energy and Engines

1. Energy and Engines By Joseph Thomas Kotch

2. Force and Motion • If the world didn’t have engines, The world wouldn’t be able to study space. We would not discover what gold is. The rockets, cars, airplanes… would be of good use to us so we can study the space and discover what gold is.

3. Forces: necessary for motion. • You body needs bones to be able to lick things and walk in nice summer days. If you didn’t have bones you would not be able to move anything of you’re body. Gravity on the earth is better than on the other planets because you can not fly away from the earth.

4. Electricity and Magnetism. • An electric force causes electrically charged objects either to attract or to repel each other. Electric charges can be positive or negative but remember that alike charges repel; opposite charges attract. There are rocks which man dig up and are called lodestones. Alike poles repel, but opposite poles attract.

5. Work and Energy Work is the result of a force moving a object. If, however, you were merely to apply force and push very hard on a wall, no work would be done because the force you were applying would not be moving anything. If we didn’t have Energy, we would not be able to play soccer, football, and many other games.

6. THE POWER OF WATER AND WIND The sun’s heat causes air to move, and produces winds. Wind is necessary because it helps the ships move and the air ballons go high and drop candies and treats for children. Water in necessary for life. If we didn’t have water, we would die in about 3 or 4 days.

7. Water, Ice, and Steam • There are three states of matter. They are: solid, liquid, and gas. Everything that takes up space is called matter. Solid things have a definite shape. Liquid and gas do not have a definite shape. These two states of matter are called fluids because they flow from place to place. Matter can change and it up to a point called THE MELTING POINT and THE FREEZING POINT. 32ºF water melts and freezes.

8. The power of Steam. • When the boiling point ( 212ºF) is reached, the collisions between molecules become so violent that they push each other far apart. Real steam is actually invisible to human’s eyes. The first practical steam engine was invented in 1712 to pump water out of mines. It worked well , but is wasted a lot of energy and water.

9. The Power of Internal Combustion. • What is combustion? The word combustion is just another word for burning. If something is noncombustible, it will not burn. If something is combustible, we mean that it will burn. Chemical energy- a special form of potential energy-is stored in fuels. But most of the energy stored in the fuel is changed into heat energy. If you had every stood next to a bonfire, you have felt the heat energy released by the wood fuel.

10. The Power of Jet Propulsion. • In 1903, two Americans- the brothers Wilbur and Orville Wright- flew the first powered plane. The engine turned a propeller, or prop, that pulled the airplane though the air. The turbojet. Most jet engines are called gas turbines because their operation depends upon a rotating turbine inside the engine. The simplest gas turbine engine is called the turbojet.

11. The Power of Rocket Engines. • There are two types of Engines: solid-fuel rocket and liquid-fuel rocket. In the process of manufacturing solid fuel for rocket engines, chemical oxidants ( oxygen-rich compounds) and chemical fuels are first mixed together as powders and then gardened into a solid substance called the propellant. The propellant is packed into the rocket’s combustion chamber.

12. Liquid-fuel Rockets. • A liquid-fuel rocket also carries both oxygen and fuel as propellants, but not in solid form. Instead, oxygen gas is condensed into a liquid by chilling it to a very cold -297ºF. Then it is stored in the oxygen tank in the rocket. Another tank in the rocket holds the fuel, such as kerosene or liquid hydrogen ( hydrogen is a gas at normal temperatures). Liquid hydrogen is the best fuel, but it must be cooled to a liquid at a temperature of-423ºF – colder even than liquid oxygen.

13. The Water Wheel • Muscles get tired, and winds stop blowing. Is there another source of energy enabling men and machines to do work? One such power source, discovered by man long ago, is the motion of water rushing downhill or flowing downstream. Flowing water has enough energy and force to move things. At least a hundred years before the birth of Christ, the Greeks and Romans thought of using the power of moving water to turn the blades of a Water Wheel. They mounted their water wheels on frames overlooking a river and connected them to millstones.

14. The Gasoline Engine. • Most automobiles are powered by an internal-combustion engine that burns gasoline as its fuel. Gasoline is a mixture of hydrocarbons, which are chemical compounds derived from petroleum, or crude oil, by refining. Besides hydrocarbons , other chemicals are also added to boost the fuel’s performance. Gasolines are graded by their ability not to explode too soon or too suddenly while being compressed within the cylinders of a gasoline engine.

15. Inside a gasoline engine. • Most automobile gasoline engines have pistons that move up and down or back and forth in the cylinders and operate on a four-stroke cycle. ( A stroke is a single movement of a piston, and a cycle is the series of movements a piston makes each time the gasoline-air mixture is burned inside the cylinder.) The first stroke is the intake stoke_ the piston moves down and draws a gasoline-air mixture from the carburetor or fuel injector into the cylinder.