Chapter 2 WAVES: SOUND & LIGHT

7th Grade Science

Waves carry energy from one place to another

1. What is the NATURE OF WAVES?

• Waves (Def.) – A wave is a disturbance that transfers energy.

• Medium – Substance or region through which a wave is transmitted.

• Speed of Waves – Depends on the properties of the medium.

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2. What is the function of the Electromagnetic spectrum?

• The Electromagnetic spectrum shows the range of different electromagnetic waves in order of increasing frequency and decreasing wavelength.

3. List some examples of Electromagnetic waves.

Electromagnetic Waves is when you listen to the radio, watch TV, or cook dinner in a microwave oven, you are using electromagnetic waves

EMW Continued

• Radio waves, television waves, and infrared rays, visible light spectrum, ultraviolet rays, X- rays, and gamma rays, are all types of electromagnetic waves. They differ by wavelength.

• Wavelength is the distance between one wave crest to the next.

4. What is the name of the material

through which a wave travels?The material through which a wavetravels is called a medium.

Some examples of medium are gases,(air), liquid (water going through a garden hose) or solids like a rope all act like a medium.

5. How do wave transfer energy?

Mechanical waves are produced whena source of energy causes a medium to vibrate.

When a vibration moves through amedium a wave results.

6. List the basic properties of waves• The basic properties of waves are

amplitude, wavelength, frequency and speed.

7.Give two examples of the high and low points found in a wave• The high point of a wave is called the

crest and the low point of a wave is called the trough

8. What is Amplitude?

• The distance the medium rises depends on the amplitude of the wave.

• Is the maximum distance that the particles of the medium carrying the wave move away from their rest position

9. What is a wavelength?

• A wavelength is the distance between two corresponding parts of a wave

10. Describe a frequency and how it is measured?

• A frequency is the number of complete waves that pass a given point in a certain amount of time.

• Frequency is measured in units called Hertz (Hz)

• A wave that occurs every second has a frequency of 1 Hz per second

11. What is the speed of a wave?

• The speed of wave is how far the wave travels in a given time.

• To calculate the speed of a wave you multiply its frequency by its wavelength.

Electromagnetic Spectrum

Waves of the Electromagnetic Spectrum

12. What is the visible spectrum of light that we can see?• Visible Spectrum – Light we can see

– Roy G. Biv – Acronym for Red, Orange, Yellow, Green, Blue, Indigo, & Violet.

– The wave length 800 nanometers to 400 nanometers