1. Heat

2. Unit A : Chapter 1 : Section 1

3. Temperature Depends on Kinetic Energy
Kinetic Energy is the energy of motion
The faster the particles of matter move, the more kinetic energy they have

4. What is Temperature? Measuring Temperature
Temperature is a measure of the Average Kinetic Energy of a substance
This means: When you measure temperature, you are measuring the average motion of the atoms

5. What is the difference between
temperature and heat?
Temperature is a measure of the average kinetic energy of atoms.
Thermometersare used to measure temperature
In other words: the faster the atoms move = the higher the temperature, & the slower the atoms move =
the lower the temperature.
Less Heat
More Heat

6. What happens when you use a thermometer to measure temperature?
What is Temperature?
What Do You Think?
What happens when you use a thermometer to measure temperature?

7. What is Temperature?
Temperature is expressed by one of 3 scales:

8. Which is warmer, the tile or the rug on a bathroom floor?
What is Heat?
What Do You Think?
Which is warmer, the tile or the rug on a bathroom floor?

9. What is Heat? Heat- A Transfer of Energy
Heat depends on how fast particles are moving AND how many particles there are.

10. Unit A : Chapter 1 : Section 1
What is heat?
This means- the more particles that make up an object, the more heat energy it has…
Unit A : Chapter 1 : Section 1

11. Unit A : Chapter 1 : Section 1

12. Unit A : Chapter 1 : Section 1
Same amount of liquid. Which one has greater available thermal energy? How do you know?
Unit A : Chapter 1 : Section 1

13. Which is warmer, the tile or the rug on a bathroom floor?
What is Heat?
What Do You Think?
Which is warmer, the tile or the rug on a bathroom floor?

14. Hot objects contain more thermal energy than cold objects.
Another word for heat is
THERMAL ENERGY.
Hot objects contain more thermal energy than cold objects.

15. Unit A : Chapter 1 : Section 1
Heat Transfer
Heat is the transfer of energy between objects or particles that are at different temperatures
Unit A : Chapter 1 : Section 1

16. What is Heat? Heat- A Transfer of Energy
Energy moves from the warmer object to the cooler object until both are the same temperature.
This is known as Thermal Equilibrium

17. Unit A : Chapter 1 : Section 1
Thermal Equilibrium
Unit A : Chapter 1 : Section 1

18. No energy transfer occurs
THERMAL EQUILIBRIUM
No energy transfer occurs

19. The point at which two objects reach the same temperature.
THERMAL EQUILIBRIUM
The point at which two objects reach the same temperature.
-Whenever they reach the same temperature, then no more energy transfer is taking place.

20. No energy transfer occurs
THERMAL EQUILIBRIUM
No energy transfer occurs

21. Unit A : Chapter 1 : Section 1

22. What is Heat?
Reaching Thermal Equilibrium

23. What is Temperature?
Thermal Expansion- As temperature rises, volume (size) increases

24. What is Temperature? Thermal Expansion
The asphalt in the road expands when heated and contracts when cooled
This results in cracks and potholes due to Thermal Expansion

25. THERMAL EXPANSION
The spreading of particles (atoms) and increased volume (size) when an object is heated is known as THERMAL EXPANSION

26. THERMAL EXPANSION.
If energy is added to atoms, they move faster. The faster they move, the further apart they move. This spreading out of atoms happens in solids, liquids and gases.
Thermal expansion is why running a tight jar lid under warm water loosens the lid.
*pg 154

27. What is Temperature? Thermal Expansion
When the metal rails in this picture heated up, they increased in length and volume
Thermal Expansion caused the rails to buckle and bend

28. Unit A : Chapter 1 : Section 1
Density & Heat
Density=the amount of matter in a given space/volume.
Can we change the density of an object?
Unit A : Chapter 1 : Section 1

29. Unit A : Chapter 1 : Section 1
Density & Heat
When does an object’s density change?
-When heat is added or removed.
Think about thermal expansion & what happens to the molecules/atoms when heated/cooled…
Unit A : Chapter 1 : Section 1

30. Unit A : Chapter 1 : Section 1
Density & Heat
When object is HEATED- molecules spread out- object LESS DENSE
When object is COOLED- molecules come together- object MORE DENSE
Unit A : Chapter 1 : Section 1

31. Why does this happen? Hot air balloon rises
Basketball or bike tire goes
flat in winter
Atmosphere
changes as you climb a mountain
Perfume can be smelled all over the room

32. Why are some objects less dense than other objects?
As the molecules of a substance spread apart, the density of the substance is lowered.
What causes molecules to spread?
Adding energy so the movement of the molecules increases.

33. What is Heat?
Energy is Transferred by 3 Methods:

34. What is Heat?
Conduction is the transfer of thermal energy through direct contact
Hold a metal wire in a flame and energy travels from atom to atom until it burns your hand

35. CONDUCTION Transfer of heat from one substance to
another by direct contact.
Happens within and between objects that touch each other
Examples: Sauce pan on a stove top, metal
spoon in a bowl of soup, ice melting in a warm hand, hot shower, walking on hot coals

36. Objects that heat up easily are called CONDUCTORS.
Metals are the best conductors
Metal objects feel cold because they conduct heat AWAY from your hand
Objects that DO NOT heat up easily are called INSULATORS. Things like glass,wood, plastic and rubber are good insulators

37. Which parts of the pan are conductors and which are insulators?

38. Which is warmer, the tile or the rug on a bathroom floor?
What is Heat?
What Do You Think?
Which is warmer, the tile or the rug on a bathroom floor?

39. What is Heat? Convection
Convection is the transfer of thermal energy by the movement of a liquid or a gas
Convection is seen as hot material rises and cool material sinks

40. CONVECTION Transfer of heat in liquids and gases ONLY
Heat moves up and down in a circular motion called a CONVECTION CURRENT
Heated liquids and gases are less dense &
rise carrying heat with them
Examples: hang gliders, soaring birds, home
furnace heating & circulating air

41. Convection currents cause the Earth’s tectonic plates to move about.

42. What is Heat?
Radiation
Radiation is the transfer of energy through matter or space through light energy, such as visible light and infrared waves
Radiation is the only type of energy transfer where the objects don’t have to touch

43. RADIATION transfer of heat through empty space in form of
infrared radiation waves (what we think of as heat
waves)
Examples: blacktop heats up on a sunny day, hot
sand on a beach, electric heaters.

44. Explain how each of these uses radiant heat.

45. Unit A : Chapter 1 : Section 1
Web Sites to Visit:
Harcourt Science: States of Matter
BBC: Science
BrainPop: States of Matter
Unit A : Chapter 1 : Section 1