Yr.9 Physics - Particles

What is density and how is it calculated?

Density is the mass per unit volume, calculated by dividing mass (kg) by volume (m³). The unit for density is kg m⁻³.

How do you measure the density of regular solids?

Measure height (H), depth (D), and width (W) to calculate volume (V = D x H x W), then measure mass (M) and calculate density (ρ = M/V).

What is the method for measuring the density of irregular solids?

Submerge the object in a filled displacement can to measure the volume of water displaced (V), then measure mass (m) and calculate density (ρ = m/V).

How do you measure the density of liquids?

Measure the mass of an empty measuring cylinder (mempty) and the mass of the full measuring cylinder (mfull), then measure the volume of the liquid (V) and calculate density (ρ = m/V).

What is conduction in the context of heating solids?

Conduction is the transfer of heat energy through a solid by the vibrations of particles, occurring from hotter to colder areas.

What is thermal conductivity?

Thermal conductivity is the property of a material to conduct heat; higher thermal conductivity indicates a better conductor and a higher rate of heat transfer.

What is specific heat capacity?

Specific heat capacity is the amount of energy needed to raise the temperature of 1 kg of a substance by 1°C, measured in joules (J).

How much energy is required to warm 1 kg of water by 1°C?

It takes 4200 J to warm 1 kg of water by 1°C.

What is the formula for finding specific heat capacity?

The formula is c = E/(mΔT), where E is energy in joules, m is mass in kg, and ΔT is the change in temperature.

What happens to particles when a material changes state?

When a material changes state, the number of particles remains the same, but their arrangement and energy change.

What is the Specific Latent Heat of Fusion?

The Specific Latent Heat of Fusion is the amount of energy required to melt or freeze 1 kg of material without changing its temperature.

What is the Specific Latent Heat of Vaporisation?

The Specific Latent Heat of Vaporisation is the amount of energy required to boil or condense 1 kg of material without changing its temperature.

What is the difference between physical and chemical changes?

Physical changes do not create new substances and are reversible, while chemical changes involve new substances and are irreversible.

What is internal energy?

Internal energy is the total energy contained in particles, comprising kinetic energy (due to motion) and potential energy (due to particle interactions).

How does temperature affect internal energy?

As temperature rises, the kinetic energy of molecules increases, leading to an increase in internal energy.

What is thermal equilibrium?

Thermal equilibrium is reached when an object has the same temperature as its surroundings, stopping heat transfer.

What is sublimation?

Sublimation is the process where a solid changes directly into a gas without becoming a liquid.

What is deposition?

Deposition is the reverse process of sublimation, where a gas changes directly into a solid.

What is the significance of mass conservation during state changes?

Mass is conserved during state changes, meaning the total mass remains the same regardless of the state.

What is the relationship between heat energy and temperature during state changes?

During state changes, heat energy is used to separate bonds between particles, so temperature does not change.

What is the role of heat energy in melting and evaporation?

Heat energy must be added to a solid to melt it or to a liquid to evaporate it.

What is the role of heat energy in condensation and freezing?

Heat energy must be removed from a gas to condense it or from a liquid to freeze it.

How does the temperature difference affect heat transfer?

The larger the temperature difference, the quicker the rate of heat transfer occurs.

What is a required practical for measuring the effect of thermal insulation on heat loss?

Use a cardboard lid with a hole, a thermometer, and insulating materials to measure temperature decrease over time.

What is the importance of measuring specific heat capacity in experiments?

Measuring specific heat capacity helps determine how much energy a material can store and how it responds to heat.