This lesson explores how waves transfer energy but not mass. You will learn about how energy is transferred by waves, as well as understand the components of waves and see examples of different types of waves.
Waves Transfer Energy
Have you ever been at a sporting event when ‘the wave’ occurred? It’s fun to watch everyone stand up when it’s their turn, creating a wave that moves through the crowd. But have you ever stopped to think about this wave and how it works?You may have noticed that while the wave itself works its way around the stadium, the people making the wave don’t have to do anything but stand up and sit back down again. In other words, the people move vertically in their seats while the wave moves horizontally around the stadium.
Examples of Energy Transfer
All of these terms are related to the amount of energy in a wave.
For example, a water wave that has both a large amplitude (is very tall) and a long wavelength is a wave with a lot of energy. This is the case with tsunamis, which are dangerous water waves that pack a big punch.Even though electromagnetic waves travel at the same speed, they can vary in their frequency and wavelength, a relationship that is inversely proportional, meaning as one gets larger the other gets smaller.So as frequency increases (meaning more waves are produced), the wavelength decreases.
And as frequency decreases (fewer waves are produced) the wavelength increases.For example, X-rays that are used to see the bones inside your body have a lot of energy because they have a high frequency and a short wavelength. On the other hand, radio waves, which is what cell phones use to transmit information, have a much lower frequency and longer wavelength, meaning they have less energy.
Waves allow energy to be transferred without the transfer of mass. This can be seen in ‘the wave’ at a sporting event, with tsunamis, and even with cell phones and medical equipment such as X-ray machines.
Energy is transferred in waves through the vibration of particles, but the particles themselves move in a perpendicular fashion to the horizontal movement of the wave. Energy is transformed between potential (stored) and kinetic (movement) energy as the particles go from rest to movement and back to rest.Waves have different components, such as their
- amplitude, or height from rest
- wavelength, or how long the wave is
- frequency, or how many waves are produced in a second
Wavelengths are measured from crest (top) to crest or from trough (bottom) to trough, and are inversely proportional to the wave’s frequency. This means that as the frequency increases the wavelength decreases, and vice versa.
Electromagnetic waves travel at the same speed but vary in their frequency and wavelength.