The Sun as an Energy Source An Introduction to the Science Behind Solar Energy www.assignmentpoint.com
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 www.assignmentpoint.com
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 www.assignmentpoint.com
Journey to the center of the Sun Corona Chromosphere Photosphere Convective Envelope Radiative Envelope Core 5 4 3 2 6 1 www.assignmentpoint.com
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 www.assignmentpoint.com
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 www.assignmentpoint.com
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. www.assignmentpoint.com
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) www.assignmentpoint.com
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 www.assignmentpoint.com
Atomic Structure: Hydrogen (H) Hydrogen contains one proton and one electron + - Helium contains two protons, two neutrons, and two electrons + - www.assignmentpoint.com
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. www.assignmentpoint.com
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. www.assignmentpoint.com
The chemical reaction... Gamma Ray (ENERGY!) + - + - + - + - + - www.assignmentpoint.com
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 www.assignmentpoint.com
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!!!!!! www.assignmentpoint.com
Solar Energy on Earth About 30% of the sun’s energy is blocked before it reaches earth Shielded by: Atmosphere Clouds www.assignmentpoint.com
Energy Path www.assignmentpoint.com
atmosphere Photosynthesis Electricity Heat Heat www.assignmentpoint.com
Energy in the form of food Photosynthesis Energy in the form of food www.assignmentpoint.com
How is this energy used? www.assignmentpoint.com
Primary Producers (Photosynthesis) The Energy Pyramid Tertiary Consumers Energy Secondary Consumers Energy Primary Consumers Energy Primary Producers (Photosynthesis) Energy www.assignmentpoint.com
Energy Transfer / 10 / 100 / 10 / 100 / 10 / 100 / 100 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? www.assignmentpoint.com
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!!! www.assignmentpoint.com
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… www.assignmentpoint.com
What is electricity? Remember the structure of an atom? Electricity is simply the flow of electrons! + - www.assignmentpoint.com
Electricity + - - WIRE This happens millions of times to produce enough electricity to power Our homes. www.assignmentpoint.com
Photovoltaic Cells This happens millions of Times to produce electricity + - - www.assignmentpoint.com
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. www.assignmentpoint.com