1. A World of Waves

2. Carrying and Causing Waves

– 3. A wave can travel through water, air, and ropes acting as a medium. Therefore waves can travel through solids, liquids or gases.

– 3. Waves are generated when a source of energy forces the matter in a medium to vibrate causing vibrations.

2. Generating Waves

– 3. Transverse Wave-. The medium creates a right angle in the direction of the wave. As the wave moves up and down, the particles move in the same direction (Ex. Rope) . Crest-high part

Troughs-low parts

Please draw and label

Examples of Transverse Waves

• S Wave (secondary waves during an earthquake to reach seismograph)

• Light waves

• Radio Waves

• Heat waves

2. Longitudinal Waves

– 3. Particles in medium move parallel to the directions the wave is traveling. (Ex. Slinky)

Compressions-particles are close

Rarefaction- particles are Spread Out

Draw and Label

Examples of Longitudinal Waves

• P Waves (can travel through solids and liquids, Primary waves are the first waves to reach seismograph during earthquake)

• travel only through solids & liquids

• Sound Waves

• Pressure Waves

2. Combination of Waves

– 3. Transverse + Longitudinal = Surface Waves

– Traveling through two different media such as water and air.

Crest or trough?

Crest or Trough?

Surface Wave

• Notice that the blue dot is not moving across the water it is only bobbing up and down and side to side creating a circular motion. The energy is moving, not the dot.

Example of Surface Wave

• Water Wave- Wind causes most water waves. The wind transfers energy to water creating water wave. Ex. Waves generated during a hurricane.

2. Properties of a Wave

– 3. Amplitude- Maximum distance particles move from rest.

– 3. Wavelength- distance between two corresponding parts of a wave

• 3. Frequency- measured in hertz (Hz). Number of complete waves that pass a given point in a certain amount of time.

Frequency = Speed / Wavelength

Solve: The speed of a wave on a rope is 50 cm/s and its wavelength is 10cm. What is the frequency?

• 3. Speed- Different waves travel at different speeds. Example: Lightening and thunder occur at the same time. However, light travels faster than sound.

» Speed = Wavelength x Frequency » Solve: A wave has the length of 5mm and a » frequency of 2 Hz. At what speed does the » wave travel?

2. Interactions of Waves

– 3. Reflection- When a wave hits an object or surface in which it can’t pass, it bounces back (Example: wave hitting the side of a pool)

• 3. Refraction- Bending of waves due to a change in speed and wavelength when passing into a new substance

• 3. Diffraction- change in direction of waves as they pass through an opening or around a barrier in their path. Water waves have the ability to travel around corners, around obstacles and through openings (Detour)