A wave is a disturbance that transfers energy from place ...

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WAVES

A wave is a disturbance that transfers energy from place to place. In science, energy is defined as the ability to do work. Material (matter) through which a wave travels is called a medium. Gases (such as air), liquids (such as water), and solids (such as ropes) all act as mediums. Waves that require a medium through which to travel are called mechanical waves.

Light waves do not require a medium and can go through a vacuum (empty space). Waves are created when a source of energy causes a medium to vibrate. A vibration is a repeated back-and-forth or up-and-down motion. This motion is the wave.

Waves are classified according to how they move.

Waves that move the medium in a direction perpendicular, or at right angles, to the direction in which the waves are traveling are called transverse waves. Transverse means “across.” The highest parts of the wave are called crests and the lowest parts are called troughs.

Longitudinal waves move the particles of the medium parallel to the direction in which the waves are traveling. If you stretch out a spring toy and push and pull one end, you can produce longitudinal waves. In some parts of the spring, the coils are close together. In other parts, the coils are more spread out. The parts where the coils are close together are called compressions. The parts where the coils are spread out, or rarefied, are called rarefactions.

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There are many different kinds of waves. However, all waves share certain properties. The basic properties of waves are amplitude, wavelength, frequency, and speed. Amplitude is the maximum distance the particles of the medium carrying the wave move away from their rest positions. You can find the amplitude of a transverse wave by measuring the distance from the rest position to a crest or to a trough. The amplitude of a longitudinal wave is a measure of how compressed or rarefied the medium becomes. Very crowded compressions and uncrowded rarefactions are like high crests and low troughs. These conditions would make a longitudinal wave with a large amplitude. The distance between two troughs or two crests of a transverse wave is the wavelength. You can find the wavelength of a longitudinal wave by measuring the distance from one compression to the next compression (or from the beginning of one rarefaction to the beginning of the next rarefaction).

The frequency of a wave is the number of complete waves that pass a given point in a certain amount of time. Frequency can also be described as the number of vibrations per second. Frequency is measured in units called hertz (Hz). A wave or vibration that occurs every second has a frequency of 1 Hz. The frequency of a wave is the same as the frequency of the vibrations that caused the wave. For example, to generate a higher-frequency wave in a rope, you must move the rope up and down more quickly. This takes more energy, so a higher-frequency wave has more energy than a lower-frequency wave with the same amplitude.

Homework Questions:

1. What is a wave?

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2. The material through which a wave travels is called a(n) _____________________________.

3. Circle the letter of each of the following that can act as mediums.

a. solids b. liquids c. gases d. empty space

|Waves that require a medium through which to travel are called __________________________. |

|Give an example of a wave that can travel through empty space. _______________________. |

4. What causes waves?

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5. What is a vibration?_____________________________________________________________________________________________________

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6. What medium is the wave above traveling through ?___________________________________________________________________

7. What is the source of energy causing the wave? _____________________________________________________________________

8. Why is the wave called a mechanical wave?

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9. What type of wave is in question 8?________________________________________________

10. The letter A in the figure above represents the _________________________________________ of the wave.

11. The letter B in the figure above represents the_________________________________________ of the wave.

12. The letter C in the figure above represents a(n) ________________________________________of the wave.

13. The letter D in the figure above represents a(n) _______________________________________ of the wave.

14. How can you find the wavelength of a longitudinal wave?

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15. Label the waves shown below as a longitudinal (compressional) or transverse. Label the compression and rarefaction of the longitudinal wave and the crest and trough Label the wavelength.

16. The amplitude of a wave is a direct measure of its _______________________________________

17. Which wave below has more energy? Explain your answer.

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18. Which wave below has more energy? Explain your answer.

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18. The number of complete waves that pass a given point in a certain amount of time is called the wave's

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All of the waves in the sketch below have the same amplitude and speed.

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19. Which wave has the longest wavelength? ________________________

20. Which has the highest frequency? ___________________

21. Which has the greatest energy? 
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