Year 7

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De Lisle Catholic Science CollegeScience
departmentKey stage 3

• Year 7
• Energy
• J.Maden

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Energy explorer
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Click here to go directly to energy transfers
Click here to go directly to unit of energy
Click here to go directly to energy in food
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What energy does

• Energy is needed to
• make things happen
• Energy cannot be created or destroyed but when
  things happen energy is
• transferred

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Imagine a world without energy
Pitch black
Stone cold
Silent as the grave
No food
No movement
No fuels
No electricity
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Chemical energy
Nuclear energy
Potential energy
Electrical energy
Kinetic energy
Light energy
Sound energy
Thermal energy
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Explaining different forms of energy
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Energy in waves
Energy in wind
Solar cells and solar panels
Chemical energy in biomass eg plants, wood and
food
Waves of thermal light energy radiate from the
Sun
Chemical energy in fossil fuels
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Electricity from fossil fuels
Fossil fuels
Solar energy
Chemical energy
Chemical energy
Burning
Kinetic energy
Heat energy
Potential energy
Light energy
Electrical energy
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Chemical
Kinetic
Light
Chemical
Gravitational potential
Kinetic
Chemical
Electrical
Electrical
Chemical
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Elastic potential
Kinetic
Elastic potential
Kinetic
Gravitational potential
Kinetic
Electrical
Kinetic
Electrical
Kinetic
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Sound
Electrical
Electrical
Sound
Infrared radiation
Thermal
Electrical
Light
Nuclear
Thermal
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No
Yes
No
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
No
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Measuring energy

• What is the unit of energy?
• the joule (J)
• What can a joule of energy do?
• pick up an apple
• What is the name for 1000J?
• the kilojoule (kJ)

Remember 1000J 1kJ
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James Prescott Joule

• Who was Joule?
• the son of a Mancunian brewer
• When was Joules birthday?
• 1818 Salford, Lancashire
• When did Joule die?
• 1889

Joules dad was so rich he built his son James
his own science laboratory in Manchester
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James Prescott Joule
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Releasing chemical energy from food
Remember 4.2J of energy will warm up 1g of water
by 1OC
10g water
Burning food
Burning releases chemical energy stored in food
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Observations
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Conclusion
Our observations suggest that
Our observations suggest that cheese puffs
contain more stored chemical energy than
marshmellows
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Evaluation
To make sure that the experiment was a fair
comparison we need to take care to
Use the same mass (or volume) of water Burn the
same mass of food
Not all of the chemical energy was transferred to
the water as thermal energy, some escaped into
the air, some heated up the glassware, the food
did not all burn
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Daily energy requirements
6000
9000
11000
9600
12000
19000
6000
9000
9600
11000
12000
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Chemical energy in food
100g Shreddies 1456kJ
45g Shreddies with milk 903kJ
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Energy in different foods
Carbohydrates should provide the body with most
of its energy
Carbohydrates
1gram of carbohydrate gives the body 170kJ of
energy
Fats are the bodies main store of chemical energy
Fats
1gram of fat can give the body 390kJ of energy
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Jouleometer
100g fat
100g carbohydrate
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Year 7Energy The end
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