Specific heat capacity
Energy required to increase the temperature of 1 kg of a substance by 1°C
/_\E
Change in energy
c
Specific heat capacity
/_\0
Change in temperature
Power units
Watts
E (for power)
Energy transferred/work done
Ways energy is transferred (4)
- Mechanically
- Heating
- Electrically
- Radiation
power equation
power = work done / time taken
system
single group of objects
what happens when a system changes
energy is transferred
closed system?
no matter or energy can enter or leave
specific heat capacity practical
- measure mass of block, wrap in insulating layer
insert thermometer - measure initial temp of block, set PD to 10V, turn on power supply, start stopwatch
- current does work on heater, transfers energy
- as block heats, record readings of temp + current every 10 mins
- calc energy transferred to heater
power
rate of energy transfer / rate of doing work
conduction
energy transferred between energy stores by collisions
biofuels
renewable energy resources created from plant products or agricultural waste
solid sphere
john dalton
atoms are solid, invisible spheres with different elements
plum pudding
jj thomson
electrons are dotted throughout a positively charged sphere
nuclear model
rutherford
small, dense, positively charged nucleus at centre with electrons orbiting it
electron shells
neils bohr
electrons orbit nucleus in fixed shells
contamination
unwanted presence of radioactive atoms
RADIOACTIVE
- inhalation or ingestion of radioactive sources
irradiation
exposed to radiation
NOT RADIOACTIVE
- presence of radioactive atoms outside the body
irradiation prevention
- thick lead apron
- step away from radiation
contamination prevention
- wear gloves
- use tongs
blue wire
- neutral
- completes circuit
