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Energy Transfers. 7I Energy resources. What is this thing called energy ?. 7I Transferring energy – Energy in food. Food is the fuel that gives us energy and keep us alive. You get your energy by “burning up” the food that you eat - but without the flames!.
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7I Energy resources What is this thing called energy ?
7I Transferring energy – Energy in food Food is the fuel that gives us energy and keep us alive. You get your energy by “burning up” the food that you eat - but without the flames! Where do you get your energy from?
7I Transferring energy – Energetic scientists Energy is measured injoules (J). The joule is named after the English physicistJames Prescott Joule, who carried out lots of work on energy. One joule is the amount of energy needed to lift an apple a distance of one metre. One joule is a small amount of energy, so you need a lot of joules of energy everyday!
7I Transferring energy – Energetic scientists The Irish physicistJohn Tyndallwas another “energetic scientist”. He was Irish. The Physics department at Bristol university is in a road named after him.
Tyndall wanted to climb the Matterhorn, a mountain in Switzerland. He worked out that all the energy needed for this task was contained in a ham sandwich. A ham sandwich, and a bottle of tea, was the only food he took with him to hike up the mountain! But just how big was that ham sandwich?
It wasn’t that large, but it did contain a large number of joules. Enough joules to climb the Matterhorn, but not enough to keep you breathing, warm and healthy
You can measure how many joules there are in food by burning the food and measuring the temperature rise in water. Sometimes this energy is released very fast though
The energy in the custard was quickly transferred to heat and sound and light. There are several different types of energy – you learnt these several weeks ago
All of these can be measured in joules – they are all energy types: • Kinetic (movement) • Elastic • Gravitational • Nuclear • Heat • Light • Sound • Electrical • Chemical
All are measured in joules But they can transfer from one type to another
Light energy is produced when we see things (our eye detects light) 15 joules of light energy each second Billions of joules of energy each second Very few joules of light
Heat energy 45 joules of heat energy each second Billions of joules of energy each second 3000 joules of energy each second
Chemical energy is stored in chemicals like food, methane gas, acids, alkalis and metals. Chemistry is a study of this energy.
Kinetic energy is found in anything that moves. More movement, more joules of Kinetic energy
And the greatest number of joules are involved with nuclear energy Small amounts on nuclear energy are released in radioactivity, but large amounts in bombs 100 000 000 000 000 joules
7I Transferring energy – Energy transformations “Energy users” transform energy from one type to another. Energy transformation Energy user 1. plant (+ Sun) A. electrical energy è heat energy B. stored chemical energy è movement energy 2. mobile phone C. light energy from the Sun è electrical energy 3. light bulb 4. toaster D. stored chemical energy è sound energy 5. solar cell E. electrical energy è light energy 6. person running è chemical energy F. light energy from the Sun Match the “energy user” to the energy transformation.
