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”