JJ Thomson - figured out stops weren't solid spheres. His measurements of charge and mass shows atoms must contain smaller negative charged particles - electrons. 'plum pudding model'

Rutherford -gold foil experiment, fired pos alpha particles at extremely thin gold sheet. - expected to pass straight through, but some deflected. idea idea the atom is concentrated in a tiny nucleus.

depends on what the object is made of. depends if it floats or sinks

how to measure - measure mass using balance. measure volume of liquid in a cylinder. volume of solid- measure length, width and height them multiply them together. To measure the volume put in an eureka can fill until just under spout add object measure displaced water.

solid - strong forces of attraction hold them close together in a fixed regular position. don't have much energy in kinetic stores so they only vibrate. melt to liquid, sublimating to gas.

liquid - weak forces of attraction, particles are close together but can move past eachother. More energy in kinetic store than solid, move randomly at low speed. evaporate to gas, freeze to solid.

Gas - no forces of attraction, more energy in kinetic energy, free to move - travel at high speeds randomly. condensate to liquid. sublimate to solid

matter is made up of tiny constantly moving particles. The warmer something is, the faster these particles move around.

In gas particles randomly bang into eachother and the wall of the container. exert a force, which cause a net force on the inside at right angles

Temp - pressure depends on how often the particles hit the wall. inc means more energy as they move faster

If you put the same amount of gas in a bigger container the pressure will dec as there are fewer collisions.

constant (pa) = pressure x volume so the new volume is constant / pressure

Pressure on outside - balloon isn't expanding means the pressure on the inside is smaller than the outside, inc inside force pushes net force outwards so inc.