Heat Transfer

Heating the Earth

Investigation 4, Part 1

ObjectivesObjectives* 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.

Weather Report

• What are the main elements of weather?

Pressure

Moisture Heat Movement of Air

Weather Report

• What are we finding the temperature of?– Air or atmosphere

• Hottest during the day?– Afternoon

• When is it coldest?– Just before daybreak

Energy Source?

• What energy source heats things up during the day?

SolarSolar HeatingHeating• Today we’re going to investigate what happens to

different earth materials when the sun shines on them.

Copy into ISN:• Focus Question is: Which material absorbs the

most heat?

-soil, rock, water or air – Make a prediction in your ISN. Explain why you chose

your answer.

Solar Heating Investigation

• What happens to different earth materials when the Sun shines on them

• Turn to “Earth Material Temperatures Lab”page 14 and 15 of your lab book.

The Setup

Each group will set up four earth material containers

Newspaper

Soil

Sand

Water

Air

Monitor the temperature changes

Thermometer

• Make sure the thermometer is below the surface of the material in the container.

• Why is this important?Water

Temperature change

• After 3 minutes, After 3 minutes, temperature = 26˚Ctemperature = 26˚C

• 26˚ - 22˚ = 4˚C26˚ - 22˚ = 4˚C

• Temperature change is Temperature change is 4˚C4˚C

• After 3 more minutes, After 3 more minutes, temperature = 29˚Ctemperature = 29˚C

• 29˚ - 22˚ = 7˚C29˚ - 22˚ = 7˚C

• Temperature change is Temperature change is 7˚C7˚C

Starting Temperature = 22˚CStarting Temperature = 22˚C

Graph the Data

• Turn to the “Earth-Material Temperatures Graph”

• Graph the temperature changes for each of the earth materials

Graphing Reminders• Use a different color to

identify the different materials (Include a key)

• Start numbers at 0, 0• Make uniform intervals• Independent variable?• Dependent Variable?

Time

Dependent

Here is what SHOULD have happened:

• Water heats up the slowest and cools the slowest.

• Air and/or soil should have heated up the most and cooled the fastest as well.

Did You Notice?

Water

Increased the least

Went down the slowest

If each earth material received the same amount of solar energy, how can you explain the differences in temperature?

Has important propertyHas important property

o Takes 5 times as much energy to heat water Takes 5 times as much energy to heat water compared to soil or sandcompared to soil or sand

Faster?• Same amount of heat energy is absorbed

equally by all materials

• Which heats up faster?

Soil

SandWater

Faster?• Same amount of heat energy is absorbed

equally by all materials

• Which heats up faster?

Soil

Sand

The solid earth materials heat up faster than water

Water vs. Soil

• Both absorb the same amount of solar energy

• Temperature of soil will be much higher than the water

SoilWater

Question

If the sun heated the earth materials, how did it do that?

• How did the energy get from the Sun to the sand, soil, water and air?

Radiant Energy

• Energy comes from the Sun as radiant energy

• Travels as waves through space and air

Radiation

• Transfer of energy by electromagnetic waves– Visible light, Infrared,

ultraviolet, microwaves, X-rays, and radio

Standing in sunshine, you are receiving energy from 150 million km away

Radiation

•Energy can travel over great distances or short distances

•Energy transfer at a distance without direct contact between the energy source and the energy receiver

RadiationRadiation• When radiant energy strikes an atom or

molecule, like a water molecule, or a molecule in soil, or air, the molecule gains energy and begins to move faster or move faster or vibrate more.vibrate more. We say the molecule absorbed the radiantradiant energyenergy.

• Absorbing radiant energy is one way energy transfers to matter.

Radiation

O

HH

Radiant energy strikes an atom or molecule Molecule gains

energy and begins to move faster

Molecular Motion

• Molecular Motion IS HEAT

• More motion in molecules = the hotter it is

SOLIDS

LIQUIDS

Differential Heating

• Different materials heat up at different rates

• Accounts for the difference in temperature of water and soil

Soil

Sand

Water

Air

Oceans and

Lakes

• Can store more heat than landmasses, even though the temperature of the water may be lower. Can store more heat than can land

• Even though the temperature

Multimedia

• Show “Heat and Energy” animation on the Weather and Water CD-Rom.

• Focus on energy transfer through radiation.

Reading

• Page 20

• Read “Thermometer: A Device to Measure Temperature”