Compare Radiation & Conduction

(Part 2)

Contrasting Case Activity 4bWeather & Water, Investigation 4

Graphing yesterday’s data• Review data collected from heating and

cooling sand and water.• Graph data.

Review of graph: Sand vs. water

Examination of radiation• What happened to the

temperature of both the sand and the water while the light was on?

• Why did this occur?

Examination of reradiation• What happened to the

temperature of both the sand and the water after the light was turned off?

• Why did this occur?

Examination of differential heating

• Which substance heated up more?

• Why did this substance heat up more?

Examination of differential heating

• Which substance cooled down more?

• Why did this substance cool down more?

Review• What was the same about each substance

heating up and cooling down? What was different?

• How was the experiment similar to the stories about the sun and the microwave? How were they different?

• How was the experiment similar to the stories about the hot spoon and the ice cube? How were they different?

Question• What heated the earth materials?

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

Radiant Energy• Energy comes from the Sun

• 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

O

HH

Radiant energy strikes an atom or molecule

Molecule gains energy and begins to move faster

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 of the water may be lower.

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”