physics 3
what is density?
the mass per unit volume of an object
what does density mean?
how dense an object is, how much mass occupies it
describe solids
least kinetic energy, highest density, particles can only vibrate in a fixed position
describe liquids
particles flow over eachother
describe gases
lowest density, most kinetic energy, particles move freely at different speeds but in straight lines
what is the change in thermal energy?
the product of the mass, specific heat capacity and temperature of a substance
what are chemical changes?
changes to the chemical structure of a substance. the substance does not usually restore its original properties when the changes are reversed
what are physical changes?
changes to the physical properties of a substance which can be reversed and original properties can be restored
what is internal energy?
the energy stored by the atoms and the molecules that make up a system. it is equal to the sum of total kinetic and potential energy of the particles in the system
what is latent heat?
the energy required for a substance to change state
what is specific heat capacity?
the amount of energy needed to increase the temperature of one kilogram of a given substance by 1 degree celsius
what is specific latent heat?
the amount of energy needed to change the state of 1 kilogram of substance whilst held at a constant temperature
what is specific latent heat of fusion?
the amount of energy needed to change the state of 1 kg of a substance from solid to liquid, whilst held at constant temp
what is specific latent heat of vaporisation?
the amount of energy needed to change the state of one kilogram of a substance from liquid to vapour at constant temp
what is sublimation?
the direct changing of a substance from a solid to vapour, without passing through the liquid phase
what is specific heat capacity measured in?
J/kg degrees celsius
what is specific latent heat measured in?
J/ kg
what is particle motion?
molecules are in a constant random motion and the temperature is determined by the kinetic energy of a substance, the higher the temperature the higher the kinetic energy
describe how you would find out the density of an irregular object and a liquid
measure the mass of the object, place a beaker under the spout of a eureka can and fill with water until water comes out of the spout. once the water has stopped dripping, remove the beaker and replace it with a measuring cylinder. submerge the object in the eureka can and collect the displaced water. the volume of water colllected equals the volume of the object
what is a systematic error?
a consistent or proportional difference between the observed and true values of something
what is a random error?
unpredictable variation between measurements that leads to a spread of values about the true value, no control over such as room temp whilst you were collecting results
what is a zero error?
any indication that a measuring system gives a false reasing when the true value of a measured quantity is zero
what is higher resolution?
the smallest change in a quantity that gives a change in the reading that can be seen
revise maths and equations from books
okay
what is the dependant variable?
what effects it
what is the independent variable?
what you can change
what is the control variable?
what stays the same