Energy Flashcards
List the 8 energy stores
Chemical, kinetic, gravitational potential, elastic potential, thermal, nuclear, electrostatic, magnetic
List the 4 energy pathways
Electrical, mechanical, heating, radiation
Is an object is stationary and then starts moving, which energy store has increased?
Kinetic
If I raise an object into the air, which energy store has increased?
Gravitational potential
What is the unit of power?
watt, W
How do you calculate power?
power = energy/time
How many watts in a kilowatt?
1000
In fuel bills, energy is given in kWh - what is this unit?
kilowatt hours
Name 3 non-renewable energy resources
Coal, oil, gas, nuclear
Name 3 renewable energy resources
Wind, hydroelectric, solar, wave, geothermal, tidal, biomass
Name 3 fossil fuels
Coal, oil, gas
How were fossil fuels formed?
Formed from the remains of plants and animals: coal was formed from dead trees and plants; while oil and gas were formed from the remains of marine life that died millions of years ago. As they were buried deeper and deeper enormous pressure and heat turned them into coal/oil/gas
What is released when fossil fuels are burnt
carbon dioxide (and other greenhouse gases)
Increasing the number of fossil fuels in the atmosphere increases what effect?
The greenhouse effect
What fuel is typically used in nuclear power stations?
uranium
As the Earth’s temperature increases due to an increase in the greenhouse effect, this can lead to…?
climate change
Some fuel is burnt to heat water. Describe the energy transfer that takes place. Use the word “store” and “pathway”
The chemical store of the fuel is transferred to the thermal store of the water via the heating pathway.
Water in a reservoir falls and drives a turbine which spins. What is wrong with the following description of the energy transfer:
Gravitational potential store to kinetic store
You need to specify the object the store is associated with e.g. the gravitational store of the water is transferred to the kinetic store of the water as it falls, which is transferred to the kinetic store of the turbine.
How do you calculate energy efficiency?
Efficiency = 100 x useful output/total input
What is the golden rule of energy transfers?
Energy cannot be created or destroyed. Energy in = energy out.
When will heat transfer occur?
When there is a temperature difference between two objects
What is the difference between temperature and the thermal store?
The thermal store also takes into account the mass of the substance
How do particles move in a warmer substance?
Faster (remember temperature is a measure of the average kinetic energy of the particles)
Why are solids the best conductors?
Particles are closely packed and regularly arranged allowing vibrations to pass from one particle to another easily.
Why are metals good conductors?
They contain free electrons which can gain energy and travel throughout the material.
What are the three types of heat transfer?
Conduction, convection, radiation
What states of matter can convection occur in?
Liquids and gases
As you heat a liquid or gas, what happens to the kinetic store of the particles?
Increases
As you heat a liquid or gas, what happens to the spaces between the particles ?
Increases
As you heat a liquid or gas, the heated part becomes _________ dense?
Less
What is wrong with the following statement - “as you heat a substance, the speed of movement of the particles increases and they expand”
The particles do not expand. The space between the particles expands.
Where do convection currents occur in real life? Give 2 examples
Near radiators, in kettles or fluid in a pan on the stove, in the atmosphere, within the Earth’s core, hot air balloons…
What is the main difference between radiation and conduction and convection?
Conduction and convection rely on particles.
What kind of wave is infrared radiation?
Transverse
If we increase the temperature of an object, what happens to the infrared radiation it emits?
It increases
Which surfaces are the best emitters and absorbers of radiation?
matt black
Which surfaces are the worst emitters and absorbers of radiation?
Shiny white or silver
Why do we use insulators?
To reduce unwanted energy transfers by heating
List 3 features in a home that can reduce unwanted energy transfers?
Draft excluders, double glazing, carpets, curtains, cavity wall insulation, loft insulation, radiator reflectors, fireplace chimney balloons
What are the main chemical elements found in plastic?
Carbon and hydrogen
- In a plastic, short chain m__________ are made into long chain p__________. The process is known as _________________________.
monomer, polymer, polymerisation
Which element (beginning with C ) is the fundamental building block of life?
Carbon
Name a process that removes carbon dioxide from the atmosphere?
Photosynthesis, dissolving atmospheric CO2 into seawater
Name 2 processes that add carbon dioxide to the atmosphere?
Weathering of limestone, combustion of hydrocarbons, respiration from animals and plants
When carbon dioxide dissolves in water, what happens to the pH?
It decreases - the water becomes more acidic.
By which process does carbon dioxide enter a plant?
Photosynthesis
Which gas makes up 78% of our atmosphere?
Nitrogen
Approximately how much oxygen is there in the air we breathe?
21%
Which layer of the Earth’s atmosphere do we live in?
Troposphere
What happens to the atmosphere as you gain altitude?
It becomes less dense
The Sun’s energy reaches the Earth and is ……………………. by the surface. The energy is emitted as …………………. (heat) radiation
absorbed. Infrared
Give two examples of greenhouse gases
water vapour, carbon dioxide, methane and nitrous oxide
What do greenhouse gases do?
Absorb infrared radiation emitted by the Earth’s surface. This causes the temperature of the atmosphere to increase.
