Energy (1) Flashcards
Name the energy store
- thermal energy
- kinetic energy
- gravitational potential energy
- elastic potential energy
- chemical energy
- magnetic energy
- electrostatic energy
- nuclear energy
What is a closed system
- systems where neither matter nor energy can enter or leave
what is work done
- energy transferred
- work done can be done when a current flows or by a force moving an object
what does kinetic energy depend on
- mass and speed
What does GPA depend on
- the objects mass, its height and the strength
What is specific heat capacity
- the amount of energy needed to heat 1kg of substance by 1 degrees
What are the instructions for the investigation of specific heat capacity
1) Place a small beaker into a larger beaker.
2) Fill the small beaker with hot water from a kettle.
3) Put a piece of cardboard over the beakers as a lid. The lid should have a hole suitable for a thermometer.
4) Place a thermometer into the smaller beaker through the hole.
5) Record the temperature of the water in the small beaker and start the stopwatch.
Record the temperature of the water every 2 minutes for 20 minutes.
6) Repeat steps 1-6, each time packing the space between the large beaker and small beaker with the chosen insulating material.
7) Plot a graph of temperature (y-axis) against time (x-axis).
What is the conservation of energy principle
- Energy can be transferred usefully, stored or dissipated but can never be created or destroyed
What is dissipated energy
- wasted energy from an energy transfer (energy is always dissipated in transfers, no transfer is 100% efficient)
What is power
- the rate of energy transfer, or the rate of doing work
what is conduction
- the process where vibrating particles transfer energy to neighbouring particles
- this mainly occurs in solids
what is convection
- where energetic particles move away from hotter to cooler regions
- only occurs in liquids and gasses
- an example is a radiator
How does lubrication reduce frictional forces
- when something moves, there’s usually always at least one frictional force acting against him
- lubricants can reduce the friction therefore reducing unwanted energy transfers
how can you reduce heat loss in a house
- thicker walls
- cavity walls, made up of an inner and outer wall with an air gap in the middle, air gap reduces energy transfer through the wall
- loft insulation reduces convection currents created in the loft
- double glazed windows having an air gap between the sheets of glass to prevent energy transfer by conduction
- draught excluders around doors and windows reduce energy transfers by convection
how do you investigate the effectiveness of materials as thermal insulators
1) Wrap a sheet of newspaper around a 100 ml beaker.
2) F ill the beaker with hot water from a kettle.
3) Put a piece of cardboard over the beaker as a lid. The lid should have a hole suitable for a thermometer.
4) Place a thermometer into the beaker through the hole.
5) Record the temperature of the water in the beaker and start the stopwatch.
6) Record the temperature of the water every 2 minutes for 20 minutes.
7) Repeat steps 1-6, each time adding another layer of newspaper around the beaker until there are 10 layers of newspaper wrapped around the beaker.
8) Plot graphs of temperature against time
what is efficiency
- How good a device is at transferring energy input to useful energy output is called efficiency.
