11 - Heat Transfer

Heat Transfer

Use this Quizizz Lesson to fill in your notes in OneNote on page 11!

There are three ways that heat can be transferred from one object or part of an object to another. These are conduction, convection, and radiation.

Multiple Choice

Thermal energy moves from..

• a colder region of an object to a hotter region.

• a hotter region of an object to a colder region.

Conduction

Conduction is a process of heat transfer from direct physical contact. Molecules in substances directly transfer kinetic energy to each other when they collide. The molecules in a hot substance strike the molecules in a colder region or object, they transfer some of their kinetic energy directly to them.

It works BEST with metals and solids. It works okay in liquids and it doesn't work in gases because the molecules are too spread out.

Conduction Examples

• Food touching a hot pan

• Ice in a cup of water

• Walking on hot sand at the beach

• Touching the handle of a spoon that’s in a cup of hot chocolate

Multiple Choice

Conduction is the process of transferring thermal energy through

• physical contact

• circulation of fluids

• electromagnetic energy

• cycling

Multiple Choice

Which is NOT an example of conduction

• A lava lamp

• Using a curling iron on hair

• Touching a hot metal spoon

Convection

Convection is a process of heat transfer in which warmer fluids rise and cooler fluids sink, due to differences in density. Fluids are gases and liquids.

The molecules in warmer fluids tend to spread out as they gain more kinetic energy, making the warmer fluid less dense than cooler fluids. A warmer fluid will rise up and float on top of a cooler fluid. If the warmer fluid then cools down after it rises, it will sink back down.

Convection Examples

• This process of convection is how warm and cool water and air circulate through the atmosphere and the ocean.

• When water boils in pot and hot water rises and cool sinks

Multiple Choice

Convection is the process of transferring thermal energy through

• physical contact

• circulation of fluids

• electromagnetic energy

• cycling

Multiple Choice

Which is NOT an example of convection

• A lava lamp

• Warm air rising off a hot parking lot in the summer

• Touching a hot metal spoon

Radiation

Radiation is the process of heat transfer through electromagnetic waves. Common EM waves are LIGHT, Microwaves, and infared waves (heat).

Radiation moves through places where there are no molecules like the vacuum of outer space. It can move through gases easily and sometimes liquids and solids.

Radiation Examples

• A microwave oven uses microwaves that will cause water molecules to vibrate very quickly. This warms up food.

• Infrared rays from the sun, a fire or a space heater

• Our bodies radiate body heat as infared waves

Multiple Choice

Radiation is the process of transferring thermal energy through

• physical contact

• circulation of fluids

• electromagnetic energy

• cycling

Multiple Choice

Which is NOT an example of radiation

• being warmed by a fire

• Touching an ice cube

• Using a microwave to make hot cocoa

Multiple Choice

Choose the correct type of heat transfer!

Water on the surface of a lake cools and circulates downward in the fall

• Conduction

• Convection

• Radiation

Multiple Choice

Choose the correct type of heat transfer!

A stick of butter melts in a hot frying pan

• Conduction

• Convection

• Radiation

Multiple Choice

Choose the correct type of heat transfer!

A microwave oven popping popcorn

• Conduction

• Convection

• Radiation

Open Ended

What materials do you want in your Solar Oven? You should collect them and build a preliminary oven this week. Make sure to take a picture of your prototype!

Multiple Select

Which kinds of heat transfer do you want to MAXIMIZE in your solar oven.

• Conduction

• Convection

• Radiation

Multiple Select

Which kinds of heat transfer do you want to MINIMIZE in your solar oven.

• Conduction

• Convection

• Radiation

Conduction in your Solar Oven is BAD!!!

• Instead, you want to stop it by INSULATING your oven

• Aluminum is a great conductor and will conduct thermal energy right out of your oven.

• (Foil is a good light reflector to use on the outside of your oven)

Multiple Choice

Plastic wrap over the top of your oven will increase this heat tranfer?

• Conduction

• Convection

• Radiation