Light Unit
MI Standards
• Energy P.EN.07.61 and P.EN.07.62
• CONTENT STATEMENT: Solar Energy Effects Nuclear reactions take place in the sun
producing heat and light. Only a tiny fraction
of the light energy from the sun reaches Earth,
providing energy to heat the Earth.
7.61
• 1. Nuclear reactions that take place in the sun
produce heat.
2. Nuclear reactions that take place in the sun
produce light.
7.62
• 1. Only a small portion of light energy from the
sun warms the Earth.
2. The atmosphere of the Earth traps heat energy
from the sun. Without the greenhouse effect the
Earth would be too cold to support life.
3. The directness of the light from the sun is in
relation to the amount of heat the Earth receives.
4. The color of the Earth’s surface affects the
amount of heat that the Earth absorbs
What you need to know.
• 1. Identify means to recognize that nuclear reactions take place in the sun
and produces heat and light.
• 2. The Sun produces a tremendous amount of light and heat
• 3. Nuclear reactions occur when nuclear particles collide to produce great
heat and light.
• 4. Heat is a form of energy associated with the motion of atoms or
molecules and capable of being transmitted through solid and fluid media
by conduction, through fluid media by convection, and through empty
space by radiation.
• 5. Light is electromagnetic radiation (radiation consisting of
electromagnetic waves, including radio waves, infrared, visible light,
ultraviolet, x-rays, and gamma rays of any wavelength).
What you need to know.
• 1. Explain how only a tiny fraction of light energy from the sun is
transformed to heat energy on Earth.
• 2. Explain how only a small part portion of light energy from the sun
produces heat energy on Earth.
• 3. The atmosphere of the Earth traps heat energy from the sun.
Without the greenhouse effect the Earth would be too cold to
support life.
• 4. The directness of the light from the sun is in relation to the
amount of heat the Earth receives.
• 5. The color of the Earth’s surface affects the amount of heat that
the Earth absorbs.
Think about…….
• 1. Where does the light we have on Earth
come from?
• 2. How is that light generated?
• 3. How does light travel?
• 4. What forms of light are there?
• 5. How are heat and light related?
Nuclear Reactions
• Describe the Sun
– 3 layers
• Core - hottest and nuclear reactions take place
• Radiation Zone – denser and hot
• Convection Zone – circulation of energy
• What processes take place in the Sun to
generate light and heat.
Nuclear Reactions
•
•
•
•
H+H
He + energy (light and heat)
Needs extreme heat and pressure to occur
Sun’s core is about 15, 000,000 ⁰C
t
Weblinks
• http://science.howstuffworks.com/sun.htm
• http://spaceweather.com
• http://www.youthttp://www.youtube.com/wa
tch?v=Ux33-5k8cjgube.com/watch?v=Ux335k8cjg