1. Waves Catch it!

2. Wave Joke The Physicist, upon seeing all the waves, gets very excited and runs into the water, disappearing. The Marine Biologist, aware of tremendous variety of marine life in the ocean, also gets very excited, and runs into the water, disappearing. The Chemist pulls out her notebook, and writes "The Physicist and the Marine Biologist are soluble in water"

3. Far out to sea, the wind disturbs the calm surface of the water. A ripple forms. As the wind continues to blow, the ripple grows into a powerful wave that can travel a great distance. Near the beach, surfers wait eagerly. They quickly paddle into deeper water to catch the monstrous wave. Surfers enjoy the power of nature as they ride the wave to shore. Far out to sea, the wind disturbs the calm surface of the water. A ripple forms. As the wind continues to blow, the ripple grows into a powerful wave that can travel a great distance. Near the beach, surfers wait eagerly. They quickly paddle into deeper water to catch the monstrous wave. Surfers enjoy the power of nature as they ride the wave to shore.

4. What are waves? Waves crashing on a beach show the tremendous energy waves can carry Waves crashing on a beach show the tremendous energy waves can carry A wave is any disturbance that transmits energy through matter or empty space.

5. Waves and Energy In science, energy is defined as the ability to do work. In science, energy is defined as the ability to do work. To understand waves, think about a boat out on the ocean. If a wave disturbs the surface of the water, it will cause anything floating on the water to be disturbed too. To understand waves, think about a boat out on the ocean. If a wave disturbs the surface of the water, it will cause anything floating on the water to be disturbed too. The energy carried by a wave can lift even a large ship as it passes. The energy carried by a wave can lift even a large ship as it passes.

6. What Carries Waves? Most waves require something to travel through. Most waves require something to travel through. Water waves travel along the surface of the water and sound waves travel through air. Water waves travel along the surface of the water and sound waves travel through air. The material through which a wave travels is called a medium. The material through which a wave travels is called a medium.

7. What Carries Waves?, Continued Sound waves, water waves and seismic waves all need a medium through which to travel. Sound waves, water waves and seismic waves all need a medium through which to travel. Waves that require a medium through which to travel are called mechanical waves. Waves that require a medium through which to travel are called mechanical waves. Gases (air), liquids (water) and solids (ropes) all act as mediums. Gases (air), liquids (water) and solids (ropes) all act as mediums.

8. What Carries Waves?, Continued Not all waves require a medium to carry them along. Not all waves require a medium to carry them along. For example, light from the sun can travel through empty space. For example, light from the sun can travel through empty space. Visible light waves, microwaves, radio waves, and X rays are examples of waves that can transfer energy without going through a medium. Visible light waves, microwaves, radio waves, and X rays are examples of waves that can transfer energy without going through a medium. These waves are called electromagnetic waves. These waves are called electromagnetic waves.

9. What Causes Waves? Waves are created when a source of energy causes a medium to vibrate. Waves are created when a source of energy causes a medium to vibrate. A vibration is a repeated back-and- forth or up-and-down motion. A vibration is a repeated back-and- forth or up-and-down motion. This motion is the source of the wave. This motion is the source of the wave.

10. What Causes Waves? Continued A moving object has energy. A moving object has energy. The moving object can transfer energy to a nearby medium, creating a wave. The moving object can transfer energy to a nearby medium, creating a wave. For example, as the propellers of a boat turn, they disturb the surface of the water. The boat’s propellers transfer energy to the water. The propellers produce a wave that travels through the water. As the boat moves through the water, it also causes waves. For example, as the propellers of a boat turn, they disturb the surface of the water. The boat’s propellers transfer energy to the water. The propellers produce a wave that travels through the water. As the boat moves through the water, it also causes waves.

11. Types of Waves Waves are classified according to how they move. Waves are classified according to how they move. The three types of waves are: The three types of waves are: – transverse waves – longitudinal waves – surface waves

12. Transverse Waves When you make a wave on a rope, the wave moves from one end of the rope to the other. When you make a wave on a rope, the wave moves from one end of the rope to the other. The rope itself moves up and down or from side to side. The rope itself moves up and down or from side to side. When the vibration of a wave is perpendicular to the direction in which the wave is traveling, the wave is called a transverse wave. When the vibration of a wave is perpendicular to the direction in which the wave is traveling, the wave is called a transverse wave.

13. Transverse Wave

14. Transverse Waves All electromagnetic waves are considered transverse waves. All electromagnetic waves are considered transverse waves.

15. Transverse Waves, Continued When you move a rope up and down, some parts of the rope are very high while some are very low. When you move a rope up and down, some parts of the rope are very high while some are very low. The highest parts of the wave are called crests. The highest parts of the wave are called crests. The lowest parts of the wave are called troughs. The lowest parts of the wave are called troughs.

16. Longitudinal Waves If you stretch out a spring toy and push and pull one end, you can produce a longitudinal wave. If you stretch out a spring toy and push and pull one end, you can produce a longitudinal wave. Longitudinal waves move the particles back and forth (or parallel) along the path that the waves move. Longitudinal waves move the particles back and forth (or parallel) along the path that the waves move. The coils in the spring move back and forth in the same direction as the wave travels. The coils in the spring move back and forth in the same direction as the wave travels.

18. Longitudinal Waves, Continued In some parts of a spring, the coils are close together and in other parts of the spring the coils are more spread out. In some parts of a spring, the coils are close together and in other parts of the spring the coils are more spread out. The parts where the coils are close together are called compressions. The parts where the coils are close together are called compressions. The parts where the coils are spread out are called rarefactions. The parts where the coils are spread out are called rarefactions.

20. Surface Waves Surface waves are combinations of transverse and longitudinal waves. Surface waves are combinations of transverse and longitudinal waves. Surface waves look like transverse waves, but the particles of the medium move in circles rather than up and down. Surface waves look like transverse waves, but the particles of the medium move in circles rather than up and down.

21. Surface Waves An object in open water will bob up and down as the energy moves through, but the object will not move forward. An object in open water will bob up and down as the energy moves through, but the object will not move forward.

22. Amplitude Some waves are very high, while others are barely noticeable. Some waves are very high, while others are barely noticeable. The distance the water rises depends on the amplitude of the wave that passes through it. The distance the water rises depends on the amplitude of the wave that passes through it. Amplitude is the maximum distance the medium carrying the wave moves away from its rest position. Amplitude is the maximum distance the medium carrying the wave moves away from its rest position.

23. Amplitude, Continued A wave with a large amplitude carries more energy than a wave with a small amplitude does. A wave with a large amplitude carries more energy than a wave with a small amplitude does.

24. Wavelength A wavelength is the distance between any point on a wave to an identical point on the next wave. A wavelength is the distance between any point on a wave to an identical point on the next wave. A wave with a shorter wavelength carries more energy than a wave with a longer wavelength does. A wave with a shorter wavelength carries more energy than a wave with a longer wavelength does.

25. Frequency Frequency is the number of complete waves that pass a given point in a certain amount of time. Frequency is the number of complete waves that pass a given point in a certain amount of time. Frequency is usually expressed in hertz (Hz) Frequency is usually expressed in hertz (Hz) A wave that occurs every second has a frequency of 1 Hz A wave that occurs every second has a frequency of 1 Hz If two waves pass every second, then the frequency of the wave is ? If two waves pass every second, then the frequency of the wave is ?