1. The Sun as an Energy Source
An Introduction to the Science Behind Solar Energy

2. A star that is very close
The Sun
-One star out of 100 billion in our galaxy
-Contains 99.8% of the mass of our solar system
-Composition
70% Hydrogen
28% Helium
2% metals
A star that is very close
To Earth

3. This is not a new concept…
The sun’s energy has been used for centuries to:
Dry clothes
Dry meats
Plants use solar energy to make food through a process called “photosynthesis”
Therefore, fossil fuels are solar energy stored for billions of years

4. Journey to the center of the Sun
Corona
Chromosphere
Photosphere
Convective Envelope
Radiative Envelope
Core 5 4 3 2 6 1

5. The Birth of Solar Energy: The Core
Solar energy is “made” in the core
T = 15.6 million degrees Celsius
156,000 times boiling water
P = 250 million atmospheres
250 million times the pressure at Earth’s surface
It is a product of nuclear fusion
The energy travels through the sun’s layers, solar system, and eventually reaches Earth

6. Nuclear Fusion A special chemical reaction
Simply, when two atomic nucleii are joined to form a larger nucleus,
Energy is given off or absorbed
Hydrogen is fused to form Helium in the sun

7. Atoms! Everything is made up of atoms
Your desk
Your body
Air
Water
They are the building block of the universe.
Different substances are made of different atoms. These are called chemicals.

8. Examples of atoms Hydrogen (part of water)
Oxygen (what we breathe and the other part of water)
Helium (what makes balloons float)
Sulfur (what makes some water stink)
Sodium and Chloride (these two make up table salt)

9. Atomic Structure Nucleus Electrons+
Nucleus
Made up of non-charged particles called NEUTRONS and positively charged particles called PROTONS
Electrons
ELECTRONS are negatively charged particles that orbit the nucleus at a certain distance -
Simple Bohr Atomic Model

10. Atomic Structure: Hydrogen (H)
Hydrogen contains one proton and one electron + -
Helium contains two protons, two neutrons, and two electrons + -

11. What is a chemical reaction?
When two or more substances called chemicals come together and change into one or more different substances.
Think of Legos
When separate, Legos are just bricks, but together they can form houses, spaceships, even people! This is the same with chemicals.

12. Solar Nuclear Fusion!!!
Four Hydrogen atoms are put together to form one Helium atom.
The atoms are happier as Helium so they give off a sigh of relief in the form of energy
This energy is called a gamma ray.

13. The chemical reaction... Gamma Ray (ENERGY!) + - + - + - + - + -

14. I thought solar energy was in the form of light?
Correct!
Gamma rays travel from the core through about 80% of the sun
It becomes harder and harder for the rays to get out of the sun so they lose energy.
When they lose energy they form photons (visible light)
They are emitted and reach Earth as photons

15. The Sun: An Energy Machine!
This reaction takes 1,000,000,000 years to complete!
386 billion billion megawatts
A power station for a city makes about 1,000 megawatts
700 million tons of Hydrogen are converted to 695 million tons of Helium every second
That means 5 million tons of energy are produced every second!!! Think about how much visible light it would take to make 5 million tons!!!!!!

16. Solar Energy on Earth
About 30% of the sun’s energy is blocked before it reaches earth
Shielded by:
Atmosphere
Clouds

17. Energy Path

18. atmosphere Photosynthesis Electricity Heat Heat

19. Energy in the form of food
Photosynthesis
Energy in the form of food

20. How is this energy used?

21. Primary Producers (Photosynthesis)
The Energy Pyramid
Tertiary Consumers
Energy
Secondary Consumers
Energy
Primary Consumers
Energy
Primary Producers (Photosynthesis)
Energy

22. Energy Transfer
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A Joule is a way to describe energy. It is named after this guy
James Prescott Joule
It takes 4.2 Joules to heat 1 gram of water 1 degree Celsius.
If 1,000,000 Joules of sunlight hit a field of grass, how is this energy
Transferred to the ecosystem?

23. Oil: Fossil Fuels
Fossil Fuels are made of thousands of years old dead plants and animals
They are buried under tons of Earth and the energy contained in the plants and animals is converted to oil.
Oil is then used to make gas for cars and other engines, including ones that create electricity!!!

24. Solar Panels Are used to “collect” solar energy
Convert solar energy to electrical energy that can power household items, such as lamps or calculators
To understand how they work we must first understand what electricity is…

25. What is electricity? Remember the structure of an atom?
Electricity is simply the flow of electrons! + -

26. Electricity + - -
WIRE
This happens millions of times to produce enough electricity to power
Our homes.

27. Photovoltaic Cells
This happens millions of Times to produce electricity + - -

28. Solar Oven Cup Cut cup in half Line inside bottom with black paper
Wrap piece of black construction paper with aluminum foil shiny side up
Make the foil into a cone insde top of cup
Place bottom inside the cone and tighten.