1. Thermal Energy
Thermal energy is the energy due to the vibration of molecules
Let us review : All matter is made up of particles (Atoms). All atoms are moving unless the temperature is at 0 degrees kelvin, called absolute zero.
Which of the states of matter below have more thermal energy? == gases!!

2. Temperature
The temperature is a measure of the average kinetic energy of the particles in an object.
We have several SI units for temperature :Fahrenheit, Celsius, and kelvin.
Kelvin is useful in science because 0 degrees Kelvin is called Absolute zero, it is the temperature at which molecules have no vibrational movement and therefore absolutely no thermal energy.

3. Thermal Energy and Temperature
An increase in thermal energy will increase temperature, because the average kinetic energy of the molecules will be increasing.

4. Thermal Energy and Mass
The more mass that the thermal energy has to be spread out over the less the temperature change will be.

5. Heat
Heat is thermal energy that flows from something at a higher temperature to something at a lower temperature.
It is a form of energy therefore it is measured in ….Joules!!

6. Specific Heat
Specific heat is the amount of heat that 1 gram of a substance can absorb causing the temperature to increase by 1 degree Celsius.
Water has a high specific heat, the same amount of energy that it takes for water to increase its temperature by 1 degree will increase aluminum’s by 5.
That is why water is used as a coolant in engines because it can absorb lots of thermal energy and protect your engine from overheating.

7. Kinetic Theory of Matter
This is the theory that all matter is made up of tiny particles called atoms that are in constant random motion.

9. Transferring Thermal Energy
There are three ways in which thermal energy can be transferred :
Conduction
Convection
Radiation

10. Convection
This is the transfer of energy in a fluid by the movement of warmer and cooler fluid from place to place.
Fluid can be both a liquid or a gas.
Heat gives energy to particles making them more energetic, as particles move faster they tend to be farther apart, as a result fluid expand as it is heated.
This causes volume to increase while mass stays the same, therefore density decreases causing the fluid to rise.
As the fluid rises, it cools and becomes more dense, and then sinks back down.
Matter is actually used to transfer energy in convection

12. Conduction
This is where thermal energy is transferred by the collision of particles in matter.
Occurs because particles are in constant motion
Heat is transferred without transferring matter, when heat is transferred through conduction.
A Heat Conductor allows easy passage of heat through it because it has electrons that are not bound to its atom. Metals are the best Conductors.
Insulators are materials that allow slow passage of heat because their electrons are held tight on their atoms.

13. Radiation
This is the transfer of energy through electromagnetic waves.
These waves can travel through space and vacuums and do not require matter to be present.
Radiation can either be :
Absorbed – the thermal energy is taken in by the object, increasing its thermal energy
Reflected – the thermal energy gets reflected, lighter objects are better at this than darker objects.
Transmitted – The Energy is able to pass through the object, not increasing its thermal energy.

14. Rates of Thermal Transfer
Depends on:
1- Temperature – the hotter the substance the more heat it can transfer
2- Color – Darker substances will absorb and transfer more heat
3- Texture – rougher substances will absorb and transfer more heat
4- Exposure of Surface – more surface exposed the more thermal energy that is transferred

15. The Thermal Energy gained=The Thermal Energy Lost
Thermodynamics
The First Law of Thermodynamics
The increase in thermal energy=work done on the system+ heat transferred
The Second Law of Thermodynamics
Due to the law of conservation of energy in a closed system (one where no energy can be lost or gained):
The Thermal Energy gained=The Thermal Energy Lost

16. Energy Lost From A System in the Real World
In the real world thermal energy is constantly “created” by friction.
As we know energy cannot be created, so friction is kinetic energy that is transformed to thermal energy.

17. Waves
A wave is a repeating disturbance or movement that transfers energy through matter or space.
There are two type of Main types waves based on what they can travel through :
1. Mechanical Waves – Require a medium to travel through Example: Sound Waves
2. Electromagnetic Waves – Do not require a medium to travel through
Example : Light Waves

18. Types of Waves Longitudinal wave Transverse Wave
oscillations are in the
direction of motion
(parallel to the motion)
Transverse Wave
oscillations are perpendicular
to the direction of
Motion

19. Physical Examples Longitudinal wave
Travel parallel to the direction of the wave movement
sound waves
earthquake P-waves
Transverse Wave
Travel perpendicular to the direction of the wave movement
water waves
earthquake S-waves
light waves

20. Wave Parameters Wavelength (l) length or size of one oscillation
Amplitude (A) strength of disturbance (intensity)
Frequency (f) repetition / how often they occur per
second

21. Wave Properties Waves are oscillations and they transport energy.
The energy of a wave is proportional to its frequency.
Fast oscillation = high frequency = high energy
Slow oscillation = low frequency = low energy
The amplitude is a measure of the wave intensity.
SOUND: amplitude corresponds to loudness
LIGHT: amplitude corresponds to brightness

22. What is the Wave length?
Measure from any identical two successive points
(nm) 5 10 15 20 25 30 35 40

23. What is the Wave length?
Measure from any identical two successive points
(nm) 5 10 15 20 25 30 35 40
30nm – 10nm = 20nm

24. What is the Wave length?
Measure from any identical two successive points
There are 4 complete oscillations depicted here
ONE WAVE = 1 COMPLETE OSCILLATION
(nm) 5 10 15 20 25 30 35 40
22.5nm - 2.5nm = 20nm

25. Frequency
Frequency = number of WAVES passing a stationary point per second (Hertz)

26. Frequency and Period
Frequency (f) = number of waves per a second
Period (T) = the time it takes for one wave
T = 1/f f = 1/T
If a source is oscillating with a period of 0.1 seconds,
what is the frequency?

27. If a source oscillates every 5 seconds, its period is
f = 1/(0.1) = 10 Hz
It will complete 10 oscillations in one second. (10 Hz)
If a source oscillates every 5 seconds, its period is
5 seconds, and then the frequency is…????

28. f = 1/5 = 0.2 Hz.

29. Wave Speed Wave speed depends on the wavelength and frequency.
wave speed v = l f
Which animal can hear a shorter wavelength?
Cats (70,000 Hertz) or Bats (120,000 Hertz)
l = v/f

30. Wave Speed v = l f Which animal can hear a shorter wavelength?
Cats (70,000 Hertz) or Bats (120,000 Hertz)
l = v/f
Higher frequency = shorter wavelength
Lower frequency = longer wavelength

31. Doppler Effect
Change in frequency of a wave due to relative motion between source and observer.
A sound wave frequency change is noticed as a change in pitch.

32. Doppler Effect for Light Waves
Change in frequency of a wave due to relative motion between source and observer.
A light wave change in frequency is noticed as a change
in “color”.
When an object:
Moves away : frequency is decreased = redshift
Moves toward : Frequency is increased = blue shift

33. Constructive Interference
Waves combine without any phase difference
When they oscillate together (“in phase”)

34. Wave Addition
Amplitude ~ Intensity

35. Destructive Interference
Waves combine differing by multiples of 1/2 wavelength
They oscillate “out-of-phase”

36. Wave Subtraction

37. The Behavior of Waves
Waves can either be absorbed, reflected, refracted, and diffracted.
When a wave is absorbed the energy is absorbed by the object that was hit by the wave.

38. Reflection
Reflection occurs when a wave strikes an object or surface and bounces off, therefore changing its direction.
The angle of incidence =angle of reflection

39. B. Refraction faster (less dense)  light bends away from the normal
bending of waves when passing from one medium to another
caused by a change in speed
slower (more dense)  light bends toward the normal
SLOWER
FASTER
faster (less dense)  light bends away from the normal

40. B. Refraction Refraction depends on…
speed of light in the medium, which depends on the density of the medium. The MORE dense the medium the slower light will travel.
wavelength of the light - shorter wavelengths (blue) bend more

41. Diffraction Diffraction is the bending of waves around a barrier.
Longer wavelengths will bend more.
Think about it like moving a small object around a corner and a large object around a corner, which has to bend more??

42. The Electromagnetic Spectrum
Electromagnetic Radiation
transverse waves produced by the motion of electrically charged particles
does not require a medium
speed in a vacuum = 300,000 km/s
electric and magnetic components are perpendicular

43. The Electromagnetic (EM) Spectrum
long 
low f
low energy
short 
high f
high energy

44. Types of EM Radiation LOW Energy High Energy
Long Wavelength Short Wavelength
Low Freq High Freq
Rabbits Meet In Very Unusual Xciting Gardens
Radio Micro Infared Visible UV X-Ray Gamma
ROYGBV

45. C. Types of EM Radiation Microwaves
Radio waves
Lowest energy EM radiation
FM - frequency modulation
AM - amplitude modulation
Microwaves
penetrate food and vibrate water & fat molecules to produce thermal energy

46. C. Types of EM Radiation Infrared Radiation (IR)
slightly lower energy than visible light
can raise the thermal energy of objects
thermogram - image made by detecting IR radiation

47. C. Types of EM Radiation Visible Light
small part of the spectrum we can see
ROY G. BIV - colors in order of increasing energy R O Y G. B I V
red
orange
yellow
green
blue
indigo
violet

48. C. Types of EM Radiation Ultraviolet Radiation (UV)
slightly higher energy than visible light
Types:
UVA - tanning, wrinkles
UVB - sunburn, cancer
UVC - most harmful, sterilization

49. C. Types of EM Radiation Ultraviolet Radiation (UV)
Ozone layer depletion = UV exposure!

50. C. Types of EM Radiation X rays higher energy than UV
can penetrate soft tissue, but not bones

51. Radiation treatment using radioactive cobalt-60.
C. Types of EM Radiation
Gamma rays
highest energy on the EM spectrum
emitted by radioactive atoms
used to kill cancerous cells
Radiation treatment using radioactive cobalt-60.

52. B. Refraction faster (less dense)  light bends away from the normal
bending of waves when passing from one medium to another
caused by a change in speed
slower (more dense)  light bends toward the normal
SLOWER
FASTER
faster (less dense)  light bends away from the normal

53. B. Refraction
Example:
View explanation.

54. C. Diffraction Diffraction bending of waves around a barrier
longer wavelengths (red) bend more - opposite of refraction