Energy_Concept_3
Using and losing Energy
Using and losing Energy
Transformers
We are surrounded by things both natural and manufactured — that turn one form of energy into another. Plants transform light into chemical energy Our bodies transform energy from plants (or plant-eating animals) into thermal, kinetic and electrical energy (our nerves and muscles use electrical impulses).
We also make machines to transform energy in various ways:
Car engines change chemical into kinetic energy. Car batteries change chemical to electrical energy which converted into light and thermal energy.
Tumble dryers change electrical into thermal and kinetic energy, and perhaps light energy (the 'on' tight). e TV sets change electrical into light, thermal and kinetic (sound) energy.
Wind turbines change kinetic into electrical energy, e Electric torches change chemical into light energy,
Energy losses
Take a rubber bal' and drop it onto a hard surface: it will bounce, and will continue to do so for several seconds. The ball starts with potential (gravitational) energy and converts this into kinetic energy as it fails. When the ball hits the ground, the kinetic energy is converted into potential (elastic) energy, which is converted back into kinetic energy as it bounces up, and so the cycle continues,
However this exchange of potential and kinetic energy does not continue indefinitely,The ball soon stops bouncing and lies still on the ground . Why is this? Firstly, some of the ball's kinetic energy is converted to kinetic (sound) energy in the ground and air each time it bounces. Secondly, the ball moving through the air causes air friction, converting the kinetic energy into thermal energy that warms the air and the ball slightly, Since it is losing energy with each bounce, the bail bounces less high each time,
Anything that moves subject to friction to a greater or lesser extent causing some thermal energy to be released. The greater the friction, the greater the heat loss — it has been known for racing car tyres to catch fire!
Conservation is a key issue modern are often concerned to conserve living things and their environment; but energy a!so needs to be conserved, and energy recycling will be crucially important in this century.
Much of our technology is concerned with changing energy from one form into another Energy never seems to be available in the form that we need: we eat food so that we can move about, keep warm and make sounds; our homes receive electricity so that we can operate machines that perform useful tasks. Whenever the form of energy is changed, some of the energy is wasted as low-level heat that escapes into the surroundings.
All the heat from slightly warm appliances builds up with time, and does not go away. This accumulation of waste energy has had a serious effect on the environment, causing global warming.
Energy transformer — something that transforms one form of energy into another; as our bodies turn chemical energy from food into movement± heat and sound
Conservation the process of reducing our overaii energy use and needs by making sure than energy is used more efficiently.
In each second the Sun emits 1 3 million times as much energy as the USA consumes in a year, 3.846 x 10 power 26 watts watts. An average sized power station may produce watts so the Sun is the same as power stations — enough for every person on this planet to have 6000,000 power stations each.
Some good posters about the uses of electrical energy are available from electricity companies. Machines such as food mixers, gas-powered curling tongs or battery-powered toys can be displayed in school to demonstrate the sources and uses of different forms of energy,