Changing Forms of Energy

Forms of Energy Energy is the ability to do work or cause a change. Energy can change an object’s motion, color, shape, temperature, or other qualities. There are many forms of energy. Sound, light, electricity, and magnetism are forms of energy.

Kinetic energy is energy due to motion Kinetic energy is energy due to motion. The amount of kinetic energy in a moving object depends on its speed and its mass. The faster an object moves, the more kinetic energy it has. The more mass an object has, the more kinetic energy it has.

Kinetic energy can change into different forms of energy. A windmill changes the kinetic energy of wind into electric energy. When a drumstick hits a drum, kinetic energy becomes sound energy. Kinetic energy can also change into thermal energy– rub your hands together, they get warmer.

Potential Energy is energy that is not causing any changes now, but could cause changes in the future. Potential Energy is sometimes called stored energy. One type of potential energy is gravitational potential energy. (demo of metal ball being dropped in clay) The higher or heavier an object is, the more gravitational potential energy it has.

Potential energy will change mostly to kinetic energy. As a car starts moving from rest, its potential energy changes to kinetic. A small amount changes to sound and thermal energy.

Chemical Energy Chemical energy is energy of the electrons that form the bonds between atoms in molecules. When fuel is burned in a car, furnace, or power plant, chemical energy is changed. Heat, light, and sound are produced.

Nuclear Energy Nuclear energy holds the protons together in the nucleus. Some things can knock a protons out of its nucleus. Then, the nuclear energy that was holding the proton in place is released. In nuclear power plants, released nuclear energy heats water until it changes into steam. The steam turns a turbine that generates electrical energy.

Sound Energy Sound is a wave of vibrations that spreads from its source. Vibration is the back-and- forth motion of an object. The areas where particles are very close together are called crests. The number of crests that pass by a point each second is the wave’s frequency. Frequency is also a measure of how fast particles are vibrating.

http://id. mind. net/~zona/mstm/physics/waves/partsOfAWave/waveParts http://id.mind.net/~zona/mstm/physics/waves/partsOfAWave/waveParts.htm

Sound can travel through solids, liquids, and gases Sound can travel through solids, liquids, and gases. But it cannot travel through a vacuum.

What is Light Energy? Light is not a vibration of particles like sound. It is a form of electromagnetic radiation, which means that it is a combination of electrical and magnetic energy. Light energy is transmitted, or given off, by electrons in an object.

The spectrum, or range, of electromagnetic radiation includes waves with many frequencies and wavelengths. For you to see an object, it must give off or reflect wavelengths of visible light.

How Does Light Move? Light travels through a vacuum about 3 hundred million meters per second. It will travel more slowly through materials such as air or water. Light bends, or refracts, whenever it enters a new material at an angle

Light waves refract when they enter the prism at an angle Light waves refract when they enter the prism at an angle. Different wavelengths refract at different angles. This causes different colors to separate from each other (rainbow). A magnifying glass contains a convex lens that bends light rays to make objects look larger. A convex lens is thickest in the middle.

A concave lens is thinner in the middle than the edges A concave lens is thinner in the middle than the edges. It can bend light rays to make an object look smaller.

What is thermal energy? (Heat Energy) Thermal energy is the total of all the kinetic and potential energy of the atoms in an object.

Conduction is the transfer of heat between objects that are in contact Conduction is the transfer of heat between objects that are in contact. (A stove will heat the pan above it by conduction) Convection is another way that heat is transferred. Convection is the transfer of heat by a moving liquid or gas. (Cool air sinks and warm air rises.) Cool water sinks under warm water. This creates a circular current called a convection current.

Radiant is a third way that heat flows from one object to another Radiant is a third way that heat flows from one object to another. Radiation is the transfer of heat by electromagnetic waves. All objects radiate heat and hot objects radiate more than cool ones.