1. Lesson 4.3 The transfer of energy as heat can be controlled.

2. Vocabulary Conduction-the process by which energy is transferred from a warmer object to a cooler object by means of physical contact. Conductor-a material that transfers energy easily. Insulator-a material that does not transfer energy easily. Convection-a process by which energy is transferred in gases and liquids, occurring when a warmer, less dense area of gas or liquid is pushed up by a cooler, more dense area of the gas or liquid. Radiation-energy that travels across distances in the form of electromagnetic waves.

3. How does energy get transferred from a warmer object to a cooler one? (heat flow) 1.Conduction 2.Convection 3.Radiation

4. Conduction Moves energy from one object to another through direct contact (touching physically). Continues as long as objects are in contact and until the temps of the objects are equal. (ex. Hands on hot bowl of soup) Can occur in a single object; energy is transferred from warmer part to cooler part of the object by heat. (ex. Putting a spoon into a cup of hot cocoa).

5. Conduction continued Conductors are materials that transfer energy easily; often have low specific heat (ex: metals) Insulators are materials that do not transfer energy easily; often have high specific heats (ex: wood, paper, and plastic foam).

6. Convection Transfers energy by the movement of large numbers of particles in the same direction within a liquid or gas. Occurs when a cooler, denser mass of the gas or liquid replaces a warmer, less dense mass of the gas or liquid by pushing it upward. Is a cycle in nature responsible for most winds and ocean currents.

7. Radiation Energy that travels as electromagnetic waves (visible light, microwaves, and infrared light). Sun is the most significant source of radiation. All objects, including you, emit radiation and release energy into their surroundings. Can travel through empty space.

8. Different materials are used to control the transfer of energy. Insulators are used to control and slow the transfer of energy from warmer objects to cooler objects because they are poor conductors of energy. A thermos works by using a hollow space between two layers to prevent conduction. Inside there is a shiny material that reflects radiation that strikes it.

9. Review Questions: What are three ways in which energy can be transferred through heat? Provide an example of each. Explain how convection is a cycle in nature. Describe how an insulator can slow a transfer of energy. Describe the similarities and differences among conduction, convection, and radiation.