HEAT

What is Temperature?Temperature is

the average kinetic energy of the particles of an object.

As temperature increases , kinetic energy of the particles increases.

How is temperature related to the movement of the particles? The faster the particles of an object move, the higher the temperature of the object.

Which particles are moving faster, those in a cup of hot tea or iced tea?

What is thermal expansion ? Thermal expansion is the increase in the volume of a substance due to an increase in temperature .

What is the official SI unit of temperature?

Kelvin

Temperature conversion formulasCelsius to Fahrenheit: oF = (9/5 * oC) + 32 oC 0FFahrenheit to Celsius: oC = (5/9) * (oF – 32) oF 0CCelsius to Kelvin: K = oC + 273 oC KKelvin to Celsius: oC = K – 273 K oC

Fill the missing blanks using the previous oF oC K

Water boils 100o

Body Temperature 37o

Room Temperature

68o

Water freezes 0o

Absolute zero 0

What is absolute zero?

The lowest temperature on Kelvin scale

(zero Kelvin) At this

temperature particles stop moving.

What is heat? Heat is the transfer of

energy between two objects that are at different temperatures.

When two objects of different temperature come in contact, energy is always transferred from the higher temperature to the lower temperature.

What is thermal energy? Thermal energy is

the total energy of the particles that make up a substance. It is measured in Joules.

Which one has more thermal energy?

What is thermal equilibrium?

Energy is transferred from the higher temperature object t o the lower temperature object until both objects reach the same temperature.

What are conductors?

Conductors are substances that conduct thermal energy.

What is an insulator? An insulator is a substance that does not

conduct thermal energy .

How is heat transferred?

Heat and temperature

change

Thermal conductivityThe rate at which a substance conducts

thermal energy.

Specific heat capacity

The amount of energy needed to change the temperature of one Kg of a substance by one degree Celsius.

Specific heat capacity of different materials:Materials Specific heat capacity

Silver 234

Copper 387

Glass 837

Wood 176

Steam 2010

Ice 2090

Aluminum 899

Water 4184

Matter and heat

Three states of matter: solid , liquid and gas.

States of matter

heat technologyHeat enginesa. A machine that uses

heat to do work.b. Heat engines burn

fuel to produce thermal energy in a process called combustion.

c. There are two types of heat engines: external combustion and internal combustion heat engines.

External combustion: fuel is burned outside the engine.

Internal combustion: fuel is burned inside the engine.

Cooling systemCooling systems are used to transfer thermal energy out a particular area so that is feels cooler.

Question: Will leaving the

refrigerator door open on a hot day help to cool the kitchen?