1. Warm Up
A pendulum with a length of 36.9 cm has a period of 1.22 sec. What is the gravitational field at the pendulum’s location?
9.78 m/s/s

2. WAVES

3. The motion of a disturbance
WAVE
The motion of a disturbance
“Energy on the move”
(not matter)

4. Material through which a wave travels
MEDIUM
Material through which a wave travels

5. Some waves require a medium, others don’t!

6. A wave that needs a medium to exist (ex: sound waves, water waves)
MECHANICAL WAVE
A wave that needs a medium to exist
(ex: sound waves, water waves)

7. A wave that does not need a medium to exist
ELECTROMAGNETIC WAVE
A wave that does not need a medium to exist
(ex: light, UV, radio)

8. Electromagnetic Spectrum

9. 2 Types of Waves
Transverse waves
Longitudinal Waves

10. Particles vibrate perpendicular to the direction of wave motion
Transverse Wave
Particles vibrate perpendicular to the direction of wave motion

11. Particles vibrate parallel to the direction of wave
Longitudinal Wave
Particles vibrate parallel to the direction of wave
motion

12. Parts of a Wave
Crest
Trough
Wavelength
Amplitude

13. Crest
Highest point
of a wave

14. Trough
Lowest point
of a wave

15. Wavelength (l) Distance between 2 similar points of a wave
(crest to crest)

16. Amplitude
Distance from crest
to equilibrium point
(half the height)

18. Measurements of Waves

19. The time it takes for one wavelength to pass a certain point
Period (T)
The time it takes for one wavelength to pass a certain point
T = 1/f

20. Number of cycles per unit time (per second)
Frequency (f)
Number of cycles per unit time (per second)
Unit: Hertz (Hz)
Hz = s-1

22. Wave Velocity (V)
V = fl
The only variable that can change a wave’s velocity is the medium!
(not amplitude, wavelength, or frequency)

23. Exit Question
Draw:
A transverse wave
A longitudinal wave

24. c = speed of light in a vacuum = 3
c = speed of light in a vacuum = 3.0 x 108 m/s (all electromagnetic waves travel at this speed)

25. Different Objects Respond to Light Waves in Different Ways

26. (Air, glass, some plastics)
TRANSPARENT
Material that transmits light rays such that the object can be clearly seen
(Air, glass, some plastics)

27. (Lampshades, frosted bulbs)
TRANSLUCENT
Material that transmits light rays, but the object can NOT be clearly seen
(Lampshades, frosted bulbs)

28. Material that DOES NOT transmit light rays
OPAQUE
Material that DOES NOT transmit light rays
(bricks, tables)

29. Material that reflects light waves
Reflecting
Material that reflects light waves
(mirrors, shiny metal)

30. Luminous
Illuminated