Review Unit 3 Energy: Conservation and Transfer Lesson 19

Congratulations! We have finished Unit 3 Energy: Conservation and Transfer. Now it is time to review what we learned.

Take out your K-W-L chart in your notebook and as we review write what you learned from this unit on force and motion. Write it in the What I Learned section.

Does heat energy behave in predictable ways?

Yes, heat energy does behave in predictable ways Yes, heat energy does behave in predictable ways. Heat will always flow in one direction from hot to cold.

When there is a temperature difference, heat will always move from higher to lower temperatures.

How does heat move from one place to another?

Heat can move from one place to another by three methods: conduction in solids, convection of fluids (liquids or gases), and radiation through anything that will allow radiation to pass.

How do we explain conduction?

Conduction occurs when two objects at different temperatures are in contact with each other. Heat flows from the warmer to the cooler object until they are both at the same temperature.

Conduction is the transfer of thermal energy between things that are touching.

The two objects here are the fire and the metal The two objects here are the fire and the metal. The metal is touching the fire and will slowly heat up until it is the same temperature as the fire.

Conduction can happen within one object Conduction can happen within one object. (For example, thermal energy can be conducted through the handle of a metal pot.)

How do we explain convection?

Convection is the movement of thermal energy by the movement of liquids or gases.

Convection occurs when warmer areas of a liquid or gas rise to cooler areas in the liquid or gas.

As this happens, cooler liquid or gas takes the place of the warmer areas which have risen higher.

You see convection when you boil water in a pan You see convection when you boil water in a pan. The bubbles of water that rise are the hotter parts of the water rising to the cooler area of water at the top of the pan.

Convection in the oceans and atmosphere helps to move thermal energy around Earth, and is an important factor influencing weather and climate.

How do we explain radiation?

Radiation is a form of energy transport consisting of electromagnetic waves traveling at the speed of light.

Radiation is a method of heat transfer that does not rely upon any contact between the heat source and the heated object.

The Sun is the main source of electromagnetic energy on Earth.

Part of this energy, light, is used by producers to make food.

Radiation can also happen in other circumstances Radiation can also happen in other circumstances. Examples of radiation would be sitting in front of a fireplace or a heater.

How can heat change the properties of a substance?

All matter is made up of atoms.

As matter heats, the atoms become more active (since heat is energy), thus making the atoms move more freely.

This looses bonds, and can make a solid object into a fluid (liquid or gas).

Nearly all substances increase in volume when they get hotter Nearly all substances increase in volume when they get hotter. Metal will expand when it gets hot.

When heated, ice will melt. A solid will become a liquid.

When we heat a liquid it will turn into a gas When we heat a liquid it will turn into a gas. We see this when we boil water. We see steam appear. Steam is water which has turned from a liquid to a gas.

Now take sometime to review the vocabulary for Unit 3 with a friend.

In our next lesson we will take a test on all the information we have learned in Unit 3.

Good Job Today! And remember to….

See you next time!