Energy (1) Flashcards
Energy stores (8)
Thermal, kinetic, gravitational potential, elastic potential, chemical, magnetic, electrostatic, nuclear,
How can energy be transferred
By heating, doing electrical work or by a force
what is the specific heat capacity of an object
the amount of energy needed to change 1kg of a substance by 1*c
Specific heat capacity Practical
- Measure the mass of the metal block using a balance
- Set up a circuit with the heater, power supply, ammeter, and voltmeter.
- Wrap insulation around the block to reduce heat loss.
- Insert heater and thermometer into the block’s holes
- Record initial temperature.
- Switch on the power supply and start the stopwatch.
- Record voltage (V) and current (I) to calculate power
- Monitor temperature rise every minute for 10 minutes
- Record the final temperature and calculate the temperature change
- Calculate energy transferred using equation then the specific heat capacity using equation
What is the conservation of energy principle
Energy is always conserved in an event
What is power
the rate of energy transfer
What is conduction and thermal conductivity
where vibrating particles transfer energy to neighbouring particles
thermal conductivity is how quickly energy is transferred through a material
What is convection
Convection is the transfer of thermal energy in gases and liquids due to the movement of particles.
It occurs because hot fluids expand, become less dense, and rise, while cooler fluids contract, become denser, and sink.
Convection currents
Created when a liquid or gas is heated from below (e.g., in a radiator or boiling water).
Warmer, less dense fluid rises and is replaced by cooler, denser fluid sinking.
This cycle continues, forming a convection current that distributes heat.
Reducing unwanted energy transfers (2)
Lubrication- reduces frictional forces making a mechanism more efficient
Insulation- reduces unwanted thermal energy transfers to the surroundings (eg, having triple-glazed windows to prevent heat loss
Insulation practical
improvements
Measure and pour a fixed volume of hot water into a beaker.
Record the starting temperature using a thermometer.
Wrap the beaker with an insulating material.
Start the stopwatch and record the temperature at regular intervals (e.g., every minute for 5).
Repeat the experiment for different insulating materials, ensuring the same starting temperature and volume of water.
Compare the temperature drop for each material to determine the best insulator
improvements- digital thermometer, water bath, shorter time intervals
What is energy efficiency
What is the only 100% efficient device
energy efficiency is a measure of how much useful energy energy is transferred from the total energy input
the only 100% efficient device is electrical heaters
What are the differences between renewable and non-renewable energy sources
non-renewable sources will eventually run out and are damaging to the environment, but they’re reliable
renewable sources will never run out, are a lot less damaging to the environment but don’t produce as much energy and are unreliable
Non-renewable energy sources examples (2)
fossil fuels, nuclear energy
Solar energy
positives and negatives
Solar panels convert sunlight into electricity.
No greenhouse gas emissions.
Free energy source (sunlight).
Low running costs.
Doesn’t work at night.
Weather-dependent.
Expensive initial installation.
Wind energy
positives and negatives
Wind turns turbine blades, spinning a generator to produce electricity.
No pollution.
Renewable and sustainable.
Can be built on land or offshore.
Unreliable (depends on wind speed).
Noisy and can spoil landscapes.
Expensive to set up.
Hydroelectric power
positives and negatives
Water stored in a dam is released, turning turbines to generate electricity.
Very reliable.
Can store energy for later use (pumped storage).
No pollution.
Requires flooding large areas, destroying habitats.
Expensive to build.
Limited to locations with rivers.
tidal energy
(positives and negatives)
Tidal barrages use rising and falling tides to turn turbines and generate electricity.
Predictable and reliable (tides always occur).
No greenhouse gas emissions.
Can harm marine life.
Expensive to build.
Only suitable for coastal areas with large tidal ranges.
wave energy generation
postivies and negatives
Floating wave machines use up and down motion of waves to generate electricity.
No pollution.
Lots of energy potential (oceans cover most of Earth).
Unreliable (depends on wave strength).
Can be difficult and expensive to maintain.
geothermal power
positives and negatives
Heat from underground (hot rocks, magma) is used to produce steam, driving turbines.
Reliable and constant energy source.
No fuel required.
Low carbon emissions.
Only works in areas with volcanic activity.
Drilling is expensive.
Can release harmful gases from underground.
Bio-fuels
positives and negatives
Burning plant material, wood, or waste to generate heat and electricity.
Uses waste materials.
Carbon-neutral (plants absorb CO₂ when growing).
Produces some CO₂ when burned.
Requires lots of land for crops.
Environmental consequences of non-renewable energy sources (4)
Releases greenhouse gases, increasing global warming
Destroys landscape to extract fossil fuels
Oil splillages
Nuclear power produces nuclear waste
