Thermal Energy & Heat

Thermal Energy & Heat

Unit2 Lesson3

What is conduction? - Page 129

• Energy as heat can be transferred in three main ways: conduction, convection, and radiation.

• Conduction is the transfer of energy as heat from one substance to another through direct contact.

• As long as two objects are in contact, conduction continues until the temperatures of the objects are equal.

• Conduction can also happen to a single object. EX: a metal spoon in a mug of hot cocoa. Energy from the warm end of the spoon will be conducted to the cooler end (the handle) until the entire spoon is 1 temperature.

What is conduction? - Page 129

• A conductor is a material that transfers heat very well.

• Metals are typically good conductors.

• An insulator is a material that is a poor conductor of heat.

• Wood, paper, and plastic foam are examples of good insulators.

Examples of Conduction

• Touching a metal spoon in a cup of hot liquid

• Putting a heating pad on your back

• Feeling the heat from a hot poker in a fireplace

• Placing a hand on top of a basket of hot rolls

Multiple Choice

What is conduction?

• Transfer of heat by the movement of a liquid or gas

• Transfer of heat through direct contact

• Transfer of heat by electromagnetic waves

Multiple Select

Which of the options below IS an example of conduction?

• An egg cooking in a hot pan

• Hot sand heats the air.

What is convection? - Page 130

• Convection is the transfer of energy as heat by the movement of a liquid or gas.

• Convection occurs when a cooler, denser mass of gas or liquid replaces a warmer, less dense mass of gas or liquid by pushing it upward.

• Hot fluid rises while cold fluid sinks.

What is convection? - Page 130

• When water is boiled, the water moves in roughly circular patterns because of convection.

• This motion is due to density differences that result from temperature differences. (hot water is less dense than cold water so it will rise and the cold water will sink)

• The motion is called a convection current.

Examples of Convection

• Macaroni rising and falling in a pot of boiling water

• Lava lamp rising and sinking

• Hot magma rising in the mantle, cold sinking

• Hot air rising in the atmosphere, cold sinking

• Hot water rising in the oceans, cold sinking

Multiple Choice

What is convection?

• Transfer of heat by the movement of a liquid or gas

• Transfer of heat through direct contact

• Transfer of heat by electromagnetic waves

Multiple Select

Which of the options below IS NOT an example of conduction?

Choose ALL that apply!

• An egg cooking in a hot pan

• Hot sand heats the air.

• Microwaving Kraft Easy Mac

What is radiation? - Page 130

• Radiation is the transfer of energy by electromagnetic waves.

• All objects, including the sun and all living things, emit radiation. The sun is the most significant source of radiation that we experience daily!

• When radiation is emitted from one object and is absorbed by another, the result is often a transfer of heat.

• Radiation can travel through empty space.

Examples of Radiation

• Laying out in the sun at a beach

• Holding your hand over a burning  match without touching it

• Feeling the warmth of a bonfire

• Holding your hands over a light bulb

Multiple Choice

What is Radiation?

• Transfer of heat by the movement of a liquid or gas

• Transfer of heat through direct contact

• Transfer of heat by electromagnetic waves

Poll

Which of the options below IS an example of radiation?

Choose ALL that apply!

• Grilling a burger over charcoal flame

• Hot sand heats the air.

• Microwaving Kraft Easy Mac

Poll

I can give the definition & an example of each of the following: conduction, convection, & radiation.

• Yes I can!

• I can for 1 of the 3

• I can for 2 of the 3

• Maybe not right now but with a little help I can!

• I'm completely lost