National Science Education Standards.
Physical Science ()Interactions of energy and matter
Waves, including sound and seismic waves, waves on water, and light waves, have energy and can transfer energy when they interact with matter.
Electromagnetic waves result when a charged object is accelerated or decelerated. Electromagnetic waves include radio waves (the longest wavelength), microwaves, infrared radiation (radiant heat), visible light, ultraviolet radiation, x-rays, and gamma rays. The energy of electromagnetic waves is carried in packets whose magnitude is inversely proportional to the wavelength.
Each kind of atom or molecule can gain or lose energy only in particular discrete amounts and thus can absorb and emit light only at wavelengths corresponding to these amounts. These wavelengths can be used to identify the substance.
In some materials, such as metals, electrons flow easily, whereas in insulating materials such as glass they can hardly flow at all. Semiconducting materials have intermediate behavior. At low temperatures some materials become superconductors and offer no resistance to the flow of electrons.
The Ohio Resource Center thanks National Academy Press for permission to display the National Science Education Standards on our website. Additional information about the standards may be obtained by going to the National Academy Press website (http://www.nap.edu).