HOMEWORK CHECK

With your closest table mates:

Write the answer to your assigned question.Remember to show work!

Resources & Reserves

Resources ≠ Reserves

• Resources – amounts of material that are known/ assumed to exist that can be extracted NOW or in the FUTURE for a POSSIBLE profit $

• Reserves – known amounts of material that can PRESENTLY be extracted for a PROFIT– “proven”

Changing estimates

• Why do reserves of resources usually last much longer than most early estimates predict?

• How does technology influence the estimates of reserves and resources?

Resource Depletion static, exponential, real world

Energy – Where does it come from?

ES 302

Objectives• What is energy?• What forms does it come in &

how do we use it?• Understand that ALL sources of

energy have costs and benefits

What is Energy?

• Energy “The ability to do work”.

• Remember: The amount of energy in the universe is constant.

What are the 2 major laws???- Laws of thermodynamics

What are the 6 major forms?- light, chemical, nuclear, mechanical, electrical, heat

Make a circuit

• Circuit = energy circle

What is electricity?• The movement of electrons

• As electrons move through metal wires, they rub against the wire – creating friction. This resistance creates heat and even light!

Where does this supply of electrons come from?

• http://www.youtube.com/watch?v=AbUjieMLFSo

• Can you list the steps?

• Check it out!

Magnets & Generators

1. Energy sources, for example coal, are burned which boils water, which produces steam

2. The steam spins a turbine3. The turbine spins a magnet4. The magnet creates a flow of electrons5. This flow of electrons travels from the power plant

to your home!

What is a watt?

• 1 watt = energy to lift 100 g (or 1 Newton) in 1.0 seconds.

• It is a measure of energy over time

Other Units of Energy• 1 calorie

• 1 Btu (British thermal unit)

• 1 Q (quad) = 1 quadrillion Btu (very large!) – The U.S. uses ~ 1 quad of energy about every 3.7

days

• 1 kWh = one kilowatt of electricity over 1 hour

Extra Resources

2nd set of notes on Energy:Usage & Quality

How can changing a light bulb reduce

greenhouse gases?

1st Law of Thermodynamics

• “Conservation of Energy Law”– Energy can neither be created nor destroyed.

• Energy in the universe is constant.• If you can’t destroy energy, you CAN change its form!

– EX: Matches– EX: Light Bulb

2nd Law of Thermodynamics

• “Energy Quality Law”– When energy changes form, some useful energy is

always degraded to lower quality, less useful energy.

• Low temperature heat is the least useful energy form!

• EX: 90% of energy in gas (chemical) is changed to heat!• Only 10% of the electricity flowing through a light bulb is

converted to light energy (the rest is heat).

What is our best immediate energy option?

1. Cut out unnecessary energy waste by improving energy efficiency

2. Transition to a renewable or solar age– Sun, wind, flowing water, biomass, geothermal,

hydrogen gas

3. Burn more coal & synthetic gas/liquids4. Natural gas5. Nuclear power

Other Units of Energy• 1 calorie = amount of heat needed to heat 1 g

of water 1 degree Celsius– 1 cal = 4.187 Joules

• 1 Btu (British thermal unit) = amount of heat energy needed to raise the temp of 1 pound of water by 1 degree Farenheit– 1 Btu = 1,054 joules; 252 calories

• 1 Q (quad) = 1 quadrillion Btu (very large!) – The U.S. uses ~ 1 quad of energy about every 3.7

days

• http://www.youtube.com/watch?v=1xPjES-sHwg&feature=related– Very slow explanation of current & voltage. Nice

analogy to water (river, lake)

• http://www.youtube.com/watch?v=k7Sz8oT8ou0– Cardboard generator constrxn (7:44)