Wave Properties

Before Video

• Waves are regular patterns of motion that transfer energy from place to place without transferring matter. Waves exhibit repeating patterns.

• When talking about waves, amplitude is the height of the wave (above its resting point). How tall or short a wave is.

• Wavelength is the distance from the peak of one wave to the peak of the next wave.

• Sound is not visible, but it travels as a longitudinal wave that causes air particles to vibrate. The particles vibrate in the form of a wave as the sound travels through the air.

After Video

• Waves transfer energy, not matter.

• Zoe and Izzy use the spring to demonstrate both transverse and longitudinal waves. Water waves are transverse waves and sound waves are longitudinal waves.

• When the music is turned on sound waves cause the salt to vibrate just like sound waves cause air particles to vibrate.

• When the phone playing music is placed inside the vacuum jar and the vacuum is turned on, all of the air is removed from the jar. Since there are no air particles for the sound waves to travel through, the sound cannot be heard even though the music is still playing.

• Transverse waves are a repeating pattern of peaks and troughs. This pattern remains the same although changes to the energy cause the peaks and troughs to get closer together or further apart (wavelength) or the peaks and troughs to be higher or lower (amplitude).

• Longitudinal waves are a repeating pattern of compression and expansion. This pattern remains the same although changes to the energy causes the compressed areas to become closer together or further apart (wavelength).

• Adding energy to a transverse wave causes the wave to become taller (amplitude increases).

• Adding energy to a wave causes the wavelength to become shorter, meaning the waves are closer together (wavelength decreases).