P3 Spaced Learning Particle Physics

Solid Liquid Gas Particles have strong bonds between them Not free to move No gaps between particles Vibrate (more) when heated Most dense state Particles have weak bonds between them Free to move Small gaps between them Move faster when heated Middle density Particles have no bonds between them Move around quickly, at random Large gaps between particles Least dense state Density = mass / volume What is the density copper if a mass of 44,800kg has a volume of 5m3? Ρ = m / V = 44,800/5 = 8960 kg/m3 The mass is measured on a top pan balance. The volume can be calculated, using length x width x height, if it is a regular cuboid. The volume of an irregular shape can be found by displacement. Place the object in water and see how much the volume of the water increases by

Specific Heat Capacity and Latent Heat The specific heat capacity of a material is the energy needed to raise the temperature of 1kg of the material by 1°C Energy = mass x specific heat capacity x temperature change How much energy is needed to raise the temperature of 2.5kg of copper (specific heat capacity = 385J/kg°C) by 14°C? E = m x c x Δθ=2.5x385x14=13,475J Latent heat is the energy needed to change the state of 1kg of a material. The latent heat of melting is the energy needed to melt 1kg of the material. The latent heat of vapourisation is the energy needed to boil it (change it from a liquid to a gas). Energy = mass x latent heat How much energy is needed to boil 3kg of water, if the latent heat of vapourisation of water =2,260,000J/kg? E = mL = 3x2,260,000 = 6,780,000J = 6780kJ

Pressure Pressure is the amount of force per square metre. A large pressure can be achieved by a large force (like a large weight) or by applying the force over a small area. Pressure = Force / Area What pressure is produced by a man with a weight of 700N standing on a board with an area of 0.25m2? P = F/A = 700/0.25 = 2800N/m2

Pressure in a liquid Pressure in a liquid is caused by the weight of the water above you. The deeper you go, the higher the pressure Pressure in liquids acts in all directions pressure = height × density of liquid × gravitational field strength g What would be the pressure at a depth of 2.5m in a swimming pool filled with water, which has a density of 1000 kg/m3? P = h x ρ x g = 2.5 x 1000 x 10 = 25,000 N/m2

Gas pressure Pressure in gases is caused by the force from the particles colliding with a surface. Each collision produces a small force which add up to produce pressure. The more particles squeezed into an area and the higher their temperature, the more pressure is produced. If the volume of the container is decreased, this also increases the pressure Atmospheric pressure is produced by the gases in the Earth’s atmosphere. This gets lower the higher you go, as the air becomes less dense.