DEFINITION OF A WAVE A wave is a transfer of energy from one point to another: Waves can exist in many forms, but the ones we will be covering are sound waves and electromagnetic waves.

ELECTROMAGNETIC VS SOUND WAVES  Sound waves are the transfer of vibrations  Sound waves require matter to move through, but can travel through any matter  Sound waves travel slower  Electromagnetic waves are light waves, which can take the form of visible light, X- rays, radiation, and UV rays  Electromagnet waves, light waves, can travel through empty space, but is stopped by opaque materials  Light waves travel faster Light waves are stopped by opaque materials, such as a wall or sheet of aluminum foil, which is why you can’t see through anything that is opaque Sound waves must be able to vibrate through particles in the air or other types of matter

STRUCTURE OF A WAVE  Crest/peak-the point at the top of a wave  Trough-the point at the bottom of a wave  Amplitude-the distance between a crest or trough and the center of the wave; the height of a wave  Wavelength-the distance between two crests or two troughs  Frequency-the number of times a crest or a trough passes a point in a certain amount of time

FREQUENCY Frequency controls the energy level of a wave, including the intensity of light, and the pitch of a sound wave, like a music note. For example, visible violet light and infrared radiation are both types of electromagnetic waves, the only difference is their frequency and energy level-

FREQUENCY (CONTINUED) The different colors of visible light are controlled by frequency, as well as other types of electromagnetic waves:

WAVES TRAVELLING THROUGH MATTER Sound waves travel at different speeds through different materials. This depends on how close together the particles in the objects are. The closer the particles are, the faster the sound wave travels. So, it travels fastest through dense solids, and slowest through air with spread out molecules.

PROPERTIES OF LIGHT WAVES  Reflection-light waves bouncing off a reflective surface, like a mirror  Refraction-light waves bending as they pass through a transparent material, like water  Diffraction-light waves being scattered and spread out as they pass through certain transparent materials, like a crystal glass

PROPERTIES OF LIGHT WAVES (CONTINUED)  Interference-when two light waves collide and combine into one wave, interfering with each other’s amplitudes  Can be constructive interference- amplitude of combined waves is greater than the wavelengths of the originals  Can be destructive interference- amplitude of combined waves is smaller than the wavelengths of the originals