Chapter 10, Section 2Standards 4b. Students know the fate of incoming solar radion in terms of reflection, absorption, and photosynthesis4c. Students know the different atmospheric gases that absorb the Earth’s thermal radiation and the mechanism and significance of the greenhouse effect.8a. Students know the thermal structure and chemical composition of the atmosphere.

Objective 1 Explain how radiant energy reaches Earth.

Objective 2 Describe how visible light and infrared energy warm Earth.

Objective 3 Summarize the processes of radiation, conduction, and convection.

Assessment Group Posters, Chapter Test

Review Daily Bellwork, Science Starters, Standards Practice

Chapter 22, Section 2

Solar EnergyKey Terms: Create a flashcard for each. The words can be found starting on page 555 or use the glossary. If you finish early, study your new words!

• Electromagnetic Spectrum• Albedo• Greenhouse effect• Conduction• Convection

Solar Energy

Heat in the atmosphere comes from the absorption of the sun’s rays by gases in the atmosphere and indirectly as the ocean and land surfaces absorb solar energy and then give off that energy as heat.

Radiation

• Radiation= all forms of energy that travel through space as wave.

• Visible light is a form of radiation the human eye can see

• UV rays, x-rays, radio waves are also radiation

• Electromagnetic Spectrum= all of the frequencies or wavelengths of electromagnetic radiation

INTERACTIVE

The Atmosphere and Solar Radiation

• As solar radiation passes through the atmosphere:• 30% is reflected back into space• 20% absorbed by clouds, dust, and gases• 50% absorbed by Earth’s surface

Scattering

Clouds, dust, water droplets, and gas molecules in the atmosphere disrupt the paths of radiation from the sun and scatter them.

This deflection causes the rays to change direction and some reflects back to space.

Why is the sky blue??As light travels through the atmosphere the smaller wavelengths (Blues) hit small particles of gas and dust, which then scatter the blue light in all directions across the sky.

Longer wavelength light (Reds) usually pass straight through the sky, however when the sun is low in the sky (sunset), only the reds can get through so we see only shades of red, not blue.

Demo

Reflection

When solar energy reaches the surface it is either absorbed or reflected.

The fraction of solar radiation that is reflected = albedo

Amount of energy absorbed or reflected depends on color, texture, composition, volume, mass, etc.

INTERACTIVE

Tell me about the GREENHOUSE EFFECT

Greenhouse Effect• The Earth’s atmosphere allows radiation to

pass through but it slows the escape of energy the radiates from the Earth’s Surface

• Car example…• Generally the amount of solar energy that

enters the atmosphere is equal to the amount that escapes into space

• Human activities may change this balance (CO2 has increased, which prevents energy from leaving the atmosphere)

BrainPop GreenHouse Effect

Conduction and ConvectionConduction: Transfer of energy as heat through direct contact of one object to anotherConvection: Movement of matter (liquids and solids) due to different densities and temperature differences, which as a result transfers heat

Cool air sinks, warm air rises

Assessment/INTERACTIVE

Greenhouse Activity