Heat TransferUnit 3 Lesson 1Pages 114-127

How are Energy and Temperature Related?

• All matter is made of molecules that are constantly moving.

• The faster they are moving the more kinetic energy they have.

Kinetic Energy

• The average kinetic energy of particles.

• Does not depend on number of particles.

• It is a measure of how hot or cold something is.

Temperature

• Is the total kinetic energy of the particles.

It depends on the number of particles

Thermal Energy

• Ex: tea in a teacup may be the same temperature as in the teapot but the tea in the pot has more thermal energy because there is more of it.

Thermal Energy

• Thermometer- An instrument used to measure the temperature, consisting of a thin, glass tube with a bulb on one end that contains a liquid, usually mercury or alcohol.

– Liquids expand when heated or contract when cooled.

– It is measured in degrees Celsius or Fahrenheit.• Freezing 0°C = 32°F• Boiling 100°C = 212°F

Measuring Temperature

• Increase in volume that results from an increase in temperature.

• Increase in temperature causes particles to move faster

• Move apart, space increase, substance expands.

Thermal Expansion

• Most substances expand when heated and contract when cooled.

• Water contracts as it is cooled until it hits 4 degrees Celsius and then it expands.

• that is why ice floats

Thermal Expansion

• D=M/V therefore thermal expansion causes a

change in Density.• Does density go up or down

with thermal expansion?

What is Heat• Heat is the energy that is

transferred between objects that are different temperatures.

Why can the temperature of land, air and water differ?

Think of a sunny day at the beach- What heats up faster?

Sand ?Water ?

• Specific Heat- the different rates at which materials become warmer or cooler are due to a property called specific heat

• Water has high Specific Heat- so therefore something with high specific heat means --it requires (a lot or a little) energy to show an increase in temperature

• Read carefully, • Highlight• Answer all questions• P115-117

• The direct transfer of energy by electromagnetic waves.

– The heat felt from a campfire or the sun’s rays. (travels in the form of Infrared radiation)

Radiation

Radiation

• The transfer of heat from one substance to another by direct contact of particles of matter.

• Fast moving molecules bump slower moving molecules and transfers some of it’s energy.

• The closer the molecules, the more effectively they conduct heat.

Conduction

Convection• The transfer of heat by movements of a

fluid. (liquids or gases)

• Molecules move from place to place carrying their energy (heat) along with them.

Convection

Heat Transfer in the Troposphere

• Radiation, conduction and convection work together to heat the troposphere.

• The surface absorbs solar energy.

• Air near the surface is warmed by radiation and conduction of heat from the surface to the air.

Heat Transfer in the Troposphere

• Convection causes most of the heating of the troposphere.

• Convection Current-– Heated molecules have more energy.– They move faster and spread further apart.– Air becomes less dense and rises.– Cooler air is more dense and sinks.– Moves into the place of the rising air.

Heat Transfer in the Troposphere