KWL Chart on WAVES What I KNOW What I WANT to know What I LEARNED

What are Waves? A WAVE is a disturbance that transfers energy from place to place. ENERGY is the ability to do work. A MEDIUM is the material through which a wave travels (gases, liquids, and solids) ELECTROMAGNETIC WAVES can travel through empty space (no medium)

How Do Waves Transfer Energy? When a wave enters a medium, it transfers energy to the medium’s particles, which bump into each other, passing the wave’s energy along. Although mechanical waves travel through a medium, they do not take the medium with them.

What Causes Waves? Mechanical waves are produced when a source of energy causes a medium to vibrate. A VIBRATION is a repeated back-and-forth or up-and-down motion. When a VIBRATION moves through a medium, a WAVE results!

Transverse Waves Waves that move the medium at right angles to the direction in which the waves travel The highest part of a transverse wave is called a CREST, and the low part is called a TROUGH

Longitudinal Waves Waves that move the medium parallel to the direction in which the waves travel. The parts where the coils are close together are called COMPRESSIONS, and the parts where the coils are spread out are called RAREFACTIONS Let’s see them both in action! Just for fun…

Properties of Waves - Amplitude AMPLITUDE - The maximum distance that the particles of the medium carrying the wave move away from their rest positions. The more energy a wave has, the greater its amplitude. Amplitude of a Transverse Wave – Measure the distance from the rest position to a crest or to a trough Amplitude of a Longitudinal Wave – Measured by how compressed or rarefied the medium becomes.

Properties of Waves - Wavelength WAVELENGTH – The distance between two corresponding parts of a wave. Wavelength of a Transverse Wave – Measure the distance from crest to crest or trough to trough Wavelength of a Longitudinal Wave – Measured by the distance between compressions.

Properties of Waves - Frequency FREQUENCY– The number of complete waves that pass a given point in a certain amount of time. Measured in units called HERTZ (Hz).

Speed Different waves travel at different speeds Speed of a wave is how far the wave travels in a given length of time If a medium does not change, the speed of a wave is constant. Speed = Wavelength x Frequency Frequency = Speed Wavelength Wavelength = Speed Frequency