1. Solar Energy 2010

2. Solar Energy and NASA NASA developed solar cells for the space program NASA developed solar cells for the space program Used to recharge batteries and powering some systems in spacecraft Used to recharge batteries and powering some systems in spacecraft Scientist’s goal was to decrease weight and increase efficiency. Scientist’s goal was to decrease weight and increase efficiency. They used to convert 6% of sunlight into electricity to a present 15% conversion rate They used to convert 6% of sunlight into electricity to a present 15% conversion rate Today solar cells are used aboard satellites and even the Mars’ rovers “Spirit and Opportunity” Today solar cells are used aboard satellites and even the Mars’ rovers “Spirit and Opportunity”

3. Spirit and Opportunity This mission was originally supposed to last 3 months and it continues today 74 months later. This mission was originally supposed to last 3 months and it continues today 74 months later. The solar panels that totally run these rovers have gone above and beyond their duty The solar panels that totally run these rovers have gone above and beyond their duty

4. Solar Cells Also called ---photovoltaic (photo meaning light and voltaic meaning producing electricity Also called ---photovoltaic (photo meaning light and voltaic meaning producing electricity Made with silicon which is plentiful and makes up ¼ the Earth’s crust -----AKA sand Made with silicon which is plentiful and makes up ¼ the Earth’s crust -----AKA sand Silicon is purified to a high degree (this is where the cost comes in to play) Silicon is purified to a high degree (this is where the cost comes in to play)

5. How do they work? Made of 2 layers Made of 2 layers 1. thin disc of almost pure silicon crystal with a little of Boron added This part has a positive electrical charge or called “P” type silicon This part has a positive electrical charge or called “P” type silicon 2. Thin layer of silicon crystal is formed over the “P” type but with phosphorus added *This part has a negative charge or called “N” type silicon

6. How do they work? cont. Two halves cancel each other out and it becomes neutral Two halves cancel each other out and it becomes neutral Sunshine hits both layers and creates a flow of electrons Sunshine hits both layers and creates a flow of electrons Viola electricity!!! Viola electricity!!!

7. Video clip solar cells solar cells solar cells solar cells