Conduction Investigation 4, Part 2 Heat Transfer Conduction Investigation 4, Part 2 TG- P.131-132

ESSENTIAL QUESTIONS * I can explain how radiant energy from the Sun heats solid and liquid materials. * I can describe how heat transfers through multiple materials. I can describe how the atmosphere heated. I can determine how to conduct a fair experiment.

In Your Notebook… Answer the following questions: What is radiant energy? 2. How does radiation affect the surface of Earth? TG- P.133

In Your Notebook… Answer the following questions: What is radiant energy? Energy that passes through space 2. How does radiation affect the surface of Earth? Earth receives energy from the Sun TG- P.133

Visible Light Is the main kind of energy from the Sun that heats the Earth Energy is transferred when light energy is absorbed by molecules in Earth’s surface, causing them to move faster, which increases the temperature! TG- P.133

Heat Transfer Walking barefoot on a hot day - What did you feel? Why? How did heat transfer from the cement to your feet? TG- P.133

Energy Transfer Challenge Heat cold water to about 30˚C without mixing the hot and cold water. Using these materials: Cold water Hot “Salt” water Cup Vial Thermometer How would you set up the experiment? TG- P.133

Hot Water Setup Material Person: Get a vial, cup, and 2 thermometers Fill the vial with cold water Fill the cup half full with hot salt water Measure and record temp of BOTH water samples Now, warm the cold water to 30 ◦ C without mixing it with the red (salt) water TG- P.133-134

The Results Were you able to raise the temperature of the cold water to 30˚C? How did heat transfer from the hot to cold water? TG- P.134

The Explanation No cold, only heat Cold is actually low levels of heat TG- P.133 Heat energy goes out of your hand into the ice cube

Heat Motion of atoms and molecules Greater motion = more heat energy TG- P.133

Conduction Energy transfer happens between molecules or atoms when they come in contact Faster moving molecules in the hand bump into the slower moving molecules in the ice Molecules in hand slow down and we feel it as cold TG- P.134

Multimedia Watch the animation of solids, liquids, and gases. Watch the animation on conduction. TG- P.135 CD-ROM Molecules in Solids, Liquids,and Gases ( Matter and Energy section).

Heat Transfer Diagram/ Ticket Out the Door How could you show the energy transfers as a flow chart from the hot water to the alcohol in the thermometer? TG- P.135

On Monday, we will explore conduction through materials BREAKPOINT On Monday, we will explore conduction through materials TG- P.135 Student Lab Notebooks P. 17

Heat Conduction Responses Complete the “Heat Conduction” worksheet on page 17 of your lab book. BREAKPOINT TG- P.135 Student Lab Notebooks P. 17

Review Remember: when two materials at different temperatures make contact, energy transfers from the hotter material to the colder material. As materials gain heat energy, the motion of their atoms and molecules increases. Molecular Motion = Heat TG- P.136

Multimedia Show thermometer animation. Draw the energy transfer going on in the animation. TG- P.136 CD-ROM Thermometer Animation ( Matter and Energy section)

Pot of Soup Metal spoon that was in a pot of cooking soup? Surprised to find that it was really hot. How did the spoon handle get so hot? Spoon handle hadn’t been in the soup TG- P.136

Conduction? Can heat conduct through an object? TG- P.136

Conduction Experiment Materials Aluminum and steel bars Temperature strips Plastic-foam cups Large plastic cups TG- P.136

Temperature Strips Liquid-crystal temperature strips Crystals inside turn colors when they reach a given temperature Different crystals produce their colors at different temperatures No color if temperature is below 30˚C or above 36˚C TG- P.137

Conduction Through Materials “Conduction through Materials” worksheet Use the materials to complete the Observations and Conclusion section TG- P.137 Student Lab Notebooks P. 19

The Results 1. The temperature strips displayed color after the metal had been in the hot water for awhile. Color indicates the temperature went up Heat energy(molecular motion) in hot water molecules transferred to metal molecules, making them move more. Heat energy (motion) moved through the metal by energy transfer from molecule to molecule in the metal Both metals conduct heat, Aluminum conducts better, heat moved up the bar faster. TG- P.137 Student Lab Notebooks P. 19

How do you think…. The Sun shines on Earth and the air gets warm. How do you think that happens? TG- P.138 Student Lab Notebooks P. 19

How it happens…. Conduction Radiation Radiant energy strikes Earth’s surface Conduction Radiation Surface molecules increase their motion Molecules of air touches the heated surface of Earth TG- P.138 The surface absorbs the energy Energy is transferred from surface to the air

Another energy transfer Even more important way that heat energy enters the atmosphere Reradiation Another way heat energy enters the atmosphere Matter radiates heat and distributes it into the atmosphere TG- P.138

Reradiation All matter radiates energy Hot matter radiates more energy than cold TG- P.138

Reradiation Sand, soil, water & air absorb energy from the Sun - they warmed up When moved to shade they cooled down Newspaper Soil Sand Water Air TG- P.138 Reradiated the energy that was absorbed to the air

What happens to the reradiated energy? Most reradiated energy is not visible, it is infrared (heat) C O Infrared energy TG- P.139 O H Then transfers the energy to N2 and O2 in the atmosphere

To review… Earth ‘s atmosphere can be heated 3 ways 1 To review… Earth ‘s atmosphere can be heated 3 ways 1. The atmosphere can absorb radiation directly from the sun 2. Air molecules gain energy when they come in contact with Earth’s surface (conduction) 3. Earth’s surface reradiates energy. Air molecules (water and carbon dioxide) absorb radiant energy.

Conductor: a substance that allows heat to travel through it easily Insulator: a substance that prevents heat from traveling through it easily

Reading Read “Heating the Atmosphere” starting on page 22. With a partner answer the “Think Questions” on page 26. TG- P.139 Student Resource Book P.22-26