1. Unit 8 Earth in Space
Solar Energy

2. Energy From the Sun
At Sun’s core: Hydrogen atoms fuse to make helium releasing HUGE amounts of energy
Electromagnetic Spectrum: the energy that is radiated from the sun

3. Energy
Multiple nuclei are joined; large amount of energy released; i.e. solar energy
A heavy nucleus is split to make smaller nuclei; large amount of energy released; i.e. nuclear power
A chemical process where whole atoms recombine; small amount of energy released; i.e. burning fossil fuels
Nuclear Fusion
Nuclear Fission
Combustion

4. Why do Nuclear Reactions yield so much Energy?
Energy released (E) is equal to change in mass (m) times the speed of light (c = 3x108 m/s)
E = mc2
Nuclear reactions release so much energy because there is a change in mass.
There is NO change in mass in chemical combustion.

5. Energy occurs in 3 forms:
Solar Energy
Heat Energy
Chemical Energy
Solar energy is converted to heat & chemical energy when it reaches Earth
Only 50% of all solar energy reaches Earth

6. Solar Energy (electromagnetic radiation) travels as transverse waves.
Frequency (f) = 1 / wavelength (λ)
Wavelength
Shorter wavelength
Higher frequency
Higher energy
Longer wavelength
Lower frequency
Lower energy

7. Radiation from the Sun occurs in different forms identified by wavelength:
Gamma Ray
Radio
Micro
wave
Visible
X Ray UV
Infrared

8. Electromagnetic Spectrum
Figure 1

9. Insolation:
The amount of solar energy received on Earth per unit of area per time.
The amount received depends on the angle that the electromagnetic wave strikes Earth, which depends on:
Time of year
Location on Earth

10. More direct rays lead to more insolation: Polar insolation is less than Equatorial insolation
Maximum insolation occurs in the visible light spectrum
Greater insolation supports more photosynthesis and more plant growth

11. Insolation
Closer to poles, rays have more angle, rays are more diffuse, insolation is lower
Figure 3
At the equator, rays have less angle, rays are more concentrated, insolation is higher

12. Figure 5
Figure 4
Figure 2