practicals

• Specific Heat Capacity Practical:

  $Change in energy=$$mass *$$SHC *$$change in temp$

  1. measure mass of block then wrap in insulating layer to reduce energy transfer
  2. measure initials temp of block set P.D = 10
  3. connect heater to power supply and turn of after 10 minutes
  4. Record the highest temperature that it reached and calculate temperature rise
  5. calculate energy transferred = P.D x current x time
• 1. attach a crocodile clips to 0cm and 100cm on the thin resistance wire
  2. record there reading on the ammeter and voltmeter
  3. move one of the crocodile clips closer until they are 90cm apart
  4. record new reading, repeat these steps using different lengths
  5. calculate resistance = R = V/I

  
• Required Practical 3: investigate resistor networks

  1. using a resistor build a series circuit
  2. record the voltmeter and ammeter reading and calculate the resistance of the resistor
  3. repeat but add another resistor and put in series circuit and measure ammeter and voltmeter
  4. arrange the resistor in parallel and close the switch and calculate resistance
• The hotter the wire is, the faster the electrons move through the wire which increases the number of collisions with atoms so the higher the resistance.
• The thicker the wire, the fewer collisions per unit length occurs between electrons and atoms so the lower the resistance.
• The greater the length of the wire, the more collisions occur between electrons and atoms so the higher the resistance.
• Required Practical 5: Density of a solid

  1. use balance to measure mass
  2. if regular solid measure width, length and height calculate volume
  3. if irregular object - submerge the eureka can filled with water, water displaced in measuring cylinder = volume of the object
  4. work out the density
• density of a liquid:

  1. Place a measuring cylinder on a balance and zero the balance
  2. pour 10ml of a liquid into the measuring cylinder + record liquid mass and repeat until cylinder full
  3. for each measurement, find density and take an average of densities
• efficiency of power stations depends on how much fuel is burnt to produce electricity and how much electricity is lost as waste heat