Energy Conversions

Do Now Questions

1) A 10.0 kg water balloon is dropped from a height of 12.0 m. Calculate the speed of the balloon just before it hits the ground.

2) A 30.0 kg child on a trampoline jumps vertically into the air at an initial speed of 1.60 m/s. Calculate how high the child will rise.

Energy Conversions

In daily life, energy conversions are constantly encountered

What evidence is there that energy conversions take place?A change in positionA change in shapeA change in temperature

Change in Position

Change in Shape

Change in Temperature

Energy Conversion in Natural Systems

Photosynthesis: converts solar energy into chemical energy

Cellular Respiration: converts chemical energy into more

usable forms of chemical

energy, and eventually

into mechanical and

heat energy

Energy Conversion in Technological Systems

Hydro-electric dams convert moving water into electrical energy

The water is held behind a dam, which falls and turns a turbine

The turbine turns a coil of wire and forces electrons to move through the wires

The newly created electrical energy cab be used to power all sorts of things, such as residential areas

Coal and natural gas can be burned and the steam can be used to turn a turbine in a similar fashion as the water in a dam

Problems?

http://www.youtube.com/watch?v=yqU02Wz9pbo

http://www.youtube.com/watch?v=cEL7yc8R42k&feature=related

Nuclear Energy Conversions

Uranium disintegrates in a nuclear reactor, releasing nuclear energy as radiation

This radiation is converted to thermal energy, which is used to heat water to steam

The steam is piped into turbines, which generate electrical energy

http://www.youtube.com/watch?v=LLwWH3dk454

http://www.youtube.com/watch?v=fjgdgAhOzXQ&feature=related

Solar Energy Conversions

Engineers have developed technologies to harness the energy released by the sun using solar panels or solar cells

Solar Energy Conversions They convert solar energy directly into electrical

energy with no moving parts They are composed of two layers of silicon, one

with phosphorus and one with boron added Electrons are bound up in the silicon crystals of

the layers, and when solar energy strikes the cell, it provides enough energy that electrons are able to break free and move within the crystals

This causes the phosphorus layer to become negatively charged, and the boron layer to become positively charged

With this separation in charge, electrons begin to flow, as within a battery

Solar Energy Conversions

http://www.youtube.com/watch?v=7T6EONdTWFE

Fuel Cells

Operates similarly to a solar cell or a battery

A Fuel Cell converts chemical energy in fuel, such as hydrogen, into electrical energy

As long as fuel is supplied, the fuel cell will continue to operate

Assignment Producing Electrical Energy

Page 169 You need to make a line graph for each of the six

sources AND a second chart that shows the percentage of the total for each source in each year.

Complete the analysis questions and hand in together.

When you’re done, work on your Transfer Task (CSI project)

When you’re done, work on your Transfer Task (CSI project)