| A | B |
|---|
| matter | anything which has mass and occupies space. |
| energy | the capacity for doing work. |
| vibrations | are repeating types of motion that disturb their surroundinds. |
| wave | this is simply the disturbance created by these vibrations. |
| mechanical waves | waves that pass through matter. |
| media | many different materials. |
| electromagnetic waves | waves that do not pass through a medium. |
| crest | the highest point on a wave. |
| trough | the lowest point on a wave. |
| wave height | the vertical disturbance between the crest and trough. |
| amplitude | half the waves height. |
| wavelength | the distance between two identical wave points. |
| frequency | number of crest that cross a given point in a second. |
| hertz | equal to one wave per second. |
| constuctive interference | the crests from two waves arrive at the same place at the same time, then the energy carried by those two crests will add together to make a larger one. |
| destrutive intererence | the crest of one wave and the trough of another arriving at the same place and time, resulting in a smaller wave. |
| diffraction | a wave that bends around a barrier. |
| refraction | when a wave travels at different speeds through different media. |
| reflection | when a wave bounces off a surface. |
| echoes | when reflected sound waves arrive a tenth of a second later than the original sound. |
| sonar | sound navigation ranging |
| echolocation | to use returning echoes to locate and avoid obstacles in a totally dark cave. |
| transverse | a specific type of wave that moves particles up and down in a direction transverse to the direction of the wave. |
| wave period | equals the amount of time it takes for each water particle to complete one whole circle. |
| breaker | this is a wave that is so steep, the wave's crest tumbles forward faster than the rest of the wave. |
| currents | waves that break in shallow water. |
| Bernoulli principle | states the pressure in a fluid decreases as the speed of the fluid increases. |
| tsunami | means "harbor wave". |
| longitudinal waves | waves that the water particles are vibrating back and forth in the same direction the wave is moving. |
| plates | igiantic hunks of rock that move across the earth's surface. |
| fault | when the rocks push together, tear apart, or grind passed each other, the rock eventually breaks apart or slips into new positions. |
| seismic waves | when the rocks move into their new position, the energy stored in them is released in the form of vibrations. |
| plate techtonics | this theory states that over millions of years the rigid plates of the earth's crust shifted and spread apart. |
| magnitude | strength of an earthquake. |
| seismograph | a machine that turns seismic waves from an earthquake into electronic signals that can be recorded onto magnetic tape. |
| Richter scale | a scale of measurement in which the number showing magnitude is calculated by a formula. |
| S waves | transverse waves that can only pass through solids. |
| P waves | very fast longitudinal waves which can travel through solids and liquids. |
| L waves | the most damaging of all waves. |
| compressions | when air particles are forced closer together. |
| rarefractions | when the particles spread out; trough |
| medium | solids, liquids, and gases. |
| decibel | one tenth of a bel. |
| pitch | high or low |
| overtone effect | when several frequencies are added together, changing the wave form and it's sound. |
