Waves

• There are 2 types of waves –Transverse waves–Longitudinal waves

Transverse Waves

What is a transverse wave?

• A transverse wave is a wave in which particles vibrate at right angles, or perpendicular, to the direction that the wave travels

• http://www.ck12.org/physical-science/Transverse-Wave-in-Physical-Science/enrichment/Transverse-Waves?referrer=assessment_dashboard_page

• Q: When a guitar string is plucked, in what direction does the wave travel? In what directions does the string vibrate?

• A: The wave travels down the string to the end. The string vibrates up and down at right angles to the direction of the wave.

Parts of a transverse wave

• A transverse wave is characterized by the high and low points reached by particles of the medium as the wave passes through. The high points are called crests, and the low points are called troughs.

Electromagnetic Waves are also transverse waves.

http://youtu.be/cfXzwh3KadE

Electromagnetic Radiation

• Electromagnetic Radiation- Waves that spread across a spectrum ranging from gamma waves to radio waves.

• Measured on a scale or “spectrum”

• Examples of devices that depend on waves from the electromagnetic spectrum

• Cell phone• X-rays• Microwave oven• Remote • Radio

• Electromagnetic waves are similar to ocean waves because they both transmit energy.

• EM waves are produced by the vibration of charged particles

• EM waves travel through space at the constant speed of light.

Waves

• Transverse Waves are characterized by 3 things:– Wavelength– Frequency– Amplitude

What is wavelength?

The distance between two crests

What is Frequency

• Waves that pass per second. • Measured in “Hertz” or Hz

Amplitude • Maximum displacement

of the wave

• In a sketch of the wave, it is the distance from the middle of the wave to the peak

• Long EM waves (like radio waves) have an increased wavelength and the decreased frequency.

• Very low energy

• As energy increases, the wavelength decreases, and the frequency increases.

What is visible light?

• Human eyes are only able to see a portion of the EM spectrum. This visible section is called visible light.

Longitudinal Waves

What is a longitudinal wave?

• Longitudinal waves cause the particles of medium to move parallel to the direction of the wave.

• They are most common in springs, where they are caused by the pushing an pulling of the spring.

• Longitudinal waves are a series of compressions and rarefactions , or expansions.

• The compressions are the areas where the particles are closest together.

• The rarefactions are the areas where the particles are furthest apart

• https://www.youtube.com/watch?v=ubRlaCCQfDk

• https://www.youtube.com/watch?v=Rbuhdo0AZDU