Waves & Light

The Electromagnetic Spectrum

Overview

  • Electromagnetic Waves:

    • Light is radiant energy that travels in transverse waves.

Key Terms

  • Wavelength: The distance between successive crests of a wave.

  • Crest: The highest point of a wave.

  • Amplitude: The height of the wave from the rest position to the crest.

  • Trough: The lowest point of a wave.

The Electromagnetic Spectrum

Description

  • A group of transverse energy waves that:

    • Are mostly invisible.

    • Can travel through empty space.

    • Travel at the same speed (the speed of light, cc).

    • Have different wavelengths and frequencies.

  • Energy Relationship:

    • Shorter waves have more energy, and longer waves have less energy.

    • Longest wavelength: Radio waves.

    • Shortest wavelength: Gamma rays.

Chart Creation

  • Instruction: Draw a chart for the different parts of the electromagnetic spectrum.

  • Note: Leave enough room to write 3 characteristics for each part of the spectrum.

Characteristics of the Electromagnetic Spectrum

1. Radio Waves

  • Key Characteristics:

    1. Longest wavelength (least energetic).

    2. Used in communications.

    3. Transmit radio and TV signals.

2. Microwaves

  • Key Characteristics:

    1. Shorter wavelength than radio waves.

    2. Absorbed by water molecules.

    3. Used to cook food.

3. Infrared Waves

  • Key Characteristics:

    1. Shorter wavelength than microwaves.

    2. Felt as heat.

    3. Hot objects give off infrared waves.

4. Visible Light

  • Key Characteristics:

    1. Shorter wavelength than infrared waves.

    2. Can be seen by humans as colors.

    3. Half of the Sun’s rays are visible light.

5. Ultraviolet Light

  • Key Characteristics:

    1. Shorter wavelength than visible light.

    2. Emits harmful radiation.

    3. Can kill living cells.

    4. Causes skin cancer.

6. X-ray Radiation

  • Key Characteristics:

    1. Shorter wavelength than ultraviolet light.

    2. Emits harmful radiation.

    3. Pass through skin, not bone.

7. Gamma Radiation

  • Key Characteristics:

    1. Shortest wavelength (highest energy).

    2. Comes from radioactivity or nuclear reactions.

    3. Emits harmful radiation.

    4. Harmful to humans.

Conclusion

  • Understanding the varieties of electromagnetic waves and their properties is essential for fields ranging from communication technologies to healthcare.