energy

• specific heat capacity required practical(liquid)


  1. measure the mass of the substance using a top pan balance
  2. measure the start temperature of the substance using a thermometer
  3. place a beaker of the substance on a heater
  4. switch on the heater to heat the substance
  5. measure the final temperature of the substance using a thermometer
  6. measure energy transferred using a joulemeter
  7. calculate the increase in temperature
  8. use the equation energy= SHC x mass x temperature
• what is specific heat capacity?

  The amount of heat energy required to raise the temperature of 1 kg of a substance by 1°C.
• what equations do you need to know for specific heat capacity?


  energy = power x time

  
  

  power = p.d x current
• Investigating methods of insulation

  1. Wrap a sheet of newspaper around a 100 ml beaker

  2. Fill 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
• investigating specific heat capacity of solids

  1. Place the immersion heater into the hole at the top of the block.
  2. Place the thermometer into the smaller hole and put a couple of drops of oil into the hole to make sure the thermometer is surrounded by hot material.
  3. Fully insulate the block by wrapping it loosely with cotton wool.
  4. Record the temperature of the block.
  5. Connect the heater to the power supply and turn it off after ten minutes.
  6. After ten minutes the temperature will still rise even though the heater has been turned off . Record the highest temperature that it reaches
• A system is an object or group of objects
• Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed.
• give 2 ways to reduce unwanted energy transfer

  lubrication and thermal insulation
• The main energy resources available for use on Earth include: fossil fuels (coal, oil and gas), nuclear fuel, bio-fuel, wind, hydroelectricity, geothermal, the tides, the Sun and water waves
• $charge flow =$$current × time$
• four types of energy transfer:

  • mechanical work - a force moving an object through a distance
  • electrical work - charges moving due to a potential difference
  • heating - due to temperature difference caused electrically or by chemical reaction
  • radiation - energy transferred as a wave, eg light and infrared - light radiation and infrared radiation are emitted from the sun
• Dissipation is a term that is often used to describe ways in which energy is wasted.
• The ways in which energy is dissipated depends on the system:

  • for a radio or set of speakers, the electrical work is transferred into useful sound waves and infrared radiation is dissipated - ie wasted as heat energy
  • for a tumble dryer, the electrical work is transferred into useful internal (thermal) energy which helps to dry clothes - energy is dissipated by sound waves
• When a force acts on an object and causes it to move through a distance, energy is transferred and work is done.
• kinetic energy is the energy of a moving object
• gravitational potential energy is the energy stored in an object due to its position above the ground
• elastic potential energy is the energy an elastic object has when its stretched or compressed
• Internal energy - the total energy of the particles in a system, including the kinetic and potential energies
• chemical energy - energy stored in chemical bonds
• nuclear energy - the energy stored in the nucleus of an atom
• magnetic energy - the energy stored in a magnetic object when near to a magnetic field
• electrostatic energy - the energy a charged object has when it is held to another charged object
• thermal conductivity - how quickly energy is transferred through the material via thermal conduction
• the rate of energy transfer trough a material depends on:

  • the thermal conductivity
  • the thickness
  • the difference in temperature
• to minimise heat loss, houses will be built with materials of low thermal conductivity
• renewable energy - energy that can be replenished and will not run out
• energy can be used for

  1. transport
  2. electricity generation
  3. heating
• advantages of fossil fuels

  • there is enough available to currently meet the demand
  • they are reliable
  • they are relatively cheap to extract from underground
• disadvantages of fossil fuels

  • they are a finite resource and will run out
  • they release carbon dioxide when combusted - contributing to the greenhouse effect
  • they release other pollutants like sulfur dioxide which causes acid rain
  • there is a risk of oil spills which would damage aquatic environments
• disadvantages of nuclear fission

  • difficult to safely dispose of
  • the waste is dangerous
  • plants are expensive to build and run
• advantages of solar power

  • cheap
  • no pollutant gasses
• disadvantages of solar power

  • no reliable
  • installation is expensive
• tidal advantage

  • reliable
  • no pollutant gasses
  • large amount of energy produced
  • no fuel costs
• tidal disadvantages

  • damage marine habitats
  • installation is expensive
  • unable to control supply
• wave wind and geo-thermal energy advantages

  • cheap to run
  • no fuel costs
  • no pollutant gases
• what are the 3 considerations that governments make when choosing an energy supply

  1. ethical
  2. social
  3. economic