Physics chapter 7 Flashcards
Renewable sources of energy
- Sun
- Water power
- Wind power
- Wave power
- Biomass fuels (Wood, Animal dung and Biogas)
- Geothermal
Non-renewable sources of energy
- Fossil fuels
i) Natural gas
ii) Petroleum
iii) Coal - Nuclear
i) Uranium
ii) Plutonium
How far away is the sun
150 million kilometers away
How long does it take the light from the sun to reach us
8 minutes
Average temperature of earch
15 degrees Celsius
How does electricity come from the sun
Using solar cells called photocells to absorb sun rays and turn them to electricity
Examples of the uses of energy from the sun
- Solar powered spacecraft
- Solar powered emergency phones in desert regions such as the Australian outback
- Most hydroelectric power comes ultimately from the sun.
Describe the water cycle
The sun’s rays cause the water to evaporate from the oceans and the land surface. They form clouds and cause rains. this is called the water cycle
Define percipitation
Water released from the clouds as rain, snow or hail. Most precipitation falls as rain.
Define evaporation
The process by which water changes from a liquid to a gas or vapor
Define condensation
It is the change in the physical state of matter from gas to liquid
How the sun is responsible for wind power
The sun heats up the atmosphere and this causes a convection current (hot air rises and cold air falls)
Define convection
The transfer of heat by the movement of a liquid or gas between areas od different tempature
How is the sun responsible for wave power
The wave is mostly due to the wind. The frictional effect of the wind on the water makes ripples that overtime increase the amount of energy it can transferred causes waves.
How does wave power work
The up and down motion of the waves must be used to turn the turbine which then turns the generator. However, rough seas are a hazardous place to work in and on calm days it produces no power.
Define biomass fuels
Biomass fuels are organic materials produce in a renewable manner.