Topic 3 Conservation of Energy Flashcards
What is the unit for measuring energy?
joule
What is the name for energy stored in a hot object?
thermal/internal
How is energy transferred from hot objects to their surroundings?
by heating/convection/conduction/radiation/evaporation
Energy stored in petrol in a car is transferred to energy stored in the moving car. What are the names for these two energy stores?
chemical, kinetic
If 100J of energy is transferred into a machine, how much is transferred out?
100J
In what way is most wasted energy transferred?
by heating
When an object is moved to a higher position, what name is given to the energy that it then stores?
gravitational potential energy
What are the energy transfers when a ball bounces?
kinetic, strain/elastic potential, kinetic
What are the energy transfers when a moving car slows down?
kinetic ? thermal energy stored in the brakes/surroundings, energy transferred by forces
Name three different types of object or substance that store energy in chemicals.
food, fuel, batteries/cells
Name two ways in which a television transfers useful energy to its surroundings.
light, sound
Name one way in which a television transfers wasted energy to its surroundings.
by heating
In what way do most machines or processes transfer wasted energy to the surroundings?
by heating
Name two machines in which energy transferred by heating is useful energy.
any two sensible answers, such as cooker or fire
When a kettle boils water, the useful energy ends up stored as thermal energy in the hot water. Where does the wasted energy end up?
thermal energy in kettle/surroundings
When a moving car brakes and comes to a stop, where does all the kinetic energy it was storing eventually end up?
thermal energy in the surroundings
When a moving car hits a wall, what happens to the kinetic energy it was originally storing?
kinetic energy of crash fragments, transferred to surroundings by sound but all ends up as thermal energy in the surroundings
What does dissipated mean?
spread out
Which wastes more energy: a more efficient machine or a less efficient machine?
less efficient
What happens to the particles in a solid when the solid gets warmer?
vibrate more
One end of a metal bar is heated. What is the name for the way energy is transferred along the bar?
conduction
What kind of materials are good thermal conductors?
metals
Name two materials that are good thermal insulators.
any two from wood, plastic, wool, etc.
What is the name for the way in which energy is transferred in a fluid
Convection
What causes a convection current?
part of the fluid being hotter than the rest/warm fluid rises
Materials that contain trapped air are good insulators. Why does the air need to be trapped?
so it cannot transfer energy by convection
How does warmth from the Sun reach the Earth?
radiation
Will a black car or a white car get hotter on a sunny day?
black
Name one thing a homeowner can do to reduce the money they spend on heating.
any from insulate loft, fit double glazing etc.
What is the unit for measuring energy?
joule
What is the name for energy stored in an object because it is in a high position?
gravitational potential energy
What is the name for energy stored in a moving object?
kinetic energy
How many grams are there in a kilogram?
1000
What is the law of conservation of energy?
total energy stays the same, or energy cannot be created or destroyed.
A ball has 5J of gravitational potential energy before it is dropped. How much kinetic energy is it storing the moment before it hits the floor ? 0J, less than 5J, 5J, more than 5J?
5J
How can you increase the gravitational potential energy stored in a box?
move it up, away from the Earth
Name a store of chemical energy.
any from coal, oil, natural gas, food, batteries/cells
What do we call the kind of energy stored inside atoms?
nuclear energy or atomic energy
When we burn a fuel, how is the energy transferred to the surroundings?
by heating
How is energy transferred to machines such as TVs and computers?
by electricity
Is electricity a fuel?
no
Name two fuels that are used by most vehicles on the roads.
petrol, diesel
Name two fuels that we call fossil fuels.
any two from coal, oil, natural gas, or oil derivatives such as petrol and diesel
What are the two products of the complete burning of fossil fuels?
carbon dioxide, water
What effect does carbon dioxide in the atmosphere have on the temperature of the Earth?
keeps it warm
What is the name for the idea that the Earth is getting warmer?
climate change/global warming
Name four different non-renewable resources.
coal, oil, natural gas, nuclear fuel/uranium
Name two different uses for natural gas.
power stations, heating homes, cooking
Name the main use for coal.
power stations
How is uranium used?
nuclear power stations
What gas do fossil-fuel power stations emit that nuclear power stations do not?
carbon dioxide
Why is adding carbon dioxide to the atmosphere a problem?
contributing to climate change
Why will supplies of fossil fuels eventually run out?
we are using them faster than they can be replaced
Name two forms of renewable energy.
two from: solar, wind, waves, tides, bio-fuel
What is the name for a fuel made from plants or from animal wastes?
bio-fuel
