Lesson 1 PropertiesWaves.pptsaaaaaaaaaaa

physics

1. Lesson 1 Properties of Waves

2. **Starter Slide**

3. Learning Objectives By the end of the lesson, you should know: 3.1 use the following units: degree (o), hertz (Hz), metre (m), metre /second (m/s), second (s). 3.2 explain the difference between longitudinal and transverse waves 3.3 know the definitions of amplitude, wavefront, frequency, wavelength and period of a wave 3.4 know that waves transfer energy and information without transferring matter

4. Waves Waves are a way of transferring energy from place to place. Waves can also transfer information.

5. Waves All these transfers take place with no matter being transferred.

6. Describing Waves When a wave moves through a substance, its particles will move from their equilibrium (resting position) and then back to equilibrium when the wave has passed. We tend to draw the motion of a wave as a repeating curved line, which can be used to join several waves together. The maximum movement of particles from equilibrium position is called its amplitude (symbol A).

7. Describing Waves The distance between a particular point on a wave and the same point on the next wave (such as from crest/peak to the next peak) is called the wavelength. The wavelength is given the Greek symbol lambda, λ. The wavelength is a distance and so usually has the unit metres, m.

8. Frequency If we count along the line we see that 5 full waves fit in the first second. This means this wave has a frequency of 5 Hz

9. Describing Waves Waves are often produced by vibrating objects, such as the diaphragm of a loudspeaker. If the object vibrates quickly it will create a large number of waves each second, if it vibrates more slowly it will create a smaller number of waves each second. The number of waves produced each second by a source is called the frequency, f. Frequency is measured with the unit hertz (Hz).

10. Frequency and Time Period

11. Wavefronts Wavefronts are seen when we place separate but similar waves side by side. A wavefront can be more properly said to be a line where all the vibrations (or oscillations) are in phase and the same distance from the wave source.

12. Types of Waves - Transverse Waves can be produced in ropes and springs. If you move one end of a spring up and down, you will see waves travelling through it. The energy carried by these waves moves along the spring from one end to the other.

13. Types of Waves - Transverse This energy transfer happens because the coils of the spring as vibrating (oscillating) up and down. Waves which have particles vibrating at a right angle to the direction of energy transfer are called transverse waves. Examples of a transverse wave include light waves and water surface waves.

14. Types of Waves – Longitudinal If you push and pull the end of a spring in a direction parallel to its axis, you can see waves once more. This time the oscillations are parallel to the direction of energy transfer. Waves which have oscillations that are parallel to the direction of energy transfer are called longitudinal waves. An example of a longitudinal wave is a sound wave.

15. **Mid-Session Plenary** E.g. mini whiteboards, gap-fill questions. The whole-class responses can then be used to inform the main activity segment of the lesson – for example, perhaps students who are struggling would benefit from a more targeted recap while other students start answering textbook questions.

16. **Activities Slide** Including appropriate differentiation Complete Lesson 1 activity sheet Chapter questions on page 66.

17. **Plenary Slide**

18. **Homework Slide**