PHYSICS: Particle Model

• What is matter made up of?

  Matter is made up of small particles called atoms.
• How do atoms exist?

  Atoms can exist on their own or together as molecules.
• How many atoms would measure 1 centimetre end to end?

  Around 100,000,000 atoms would measure 1 centimetre end to end.
• What does density describe?

  • Density describes how closely packed the particles are in a solid, liquid, or gas.
  • It is a measure of compactness and the ratio of mass to volume.
• In what units is density usually measured?

  Density is usually measured in kilograms per metre cubed (kg/m³) or grams per centimetre cubed (g/cm³).
• What is mass?

  Mass is the amount of matter an object contains.
• How is mass measured?

  Mass is measured in kilograms (kg) or grams (g).
• What is volume?

  Volume is a measure of the amount of space or capacity an object occupies.
• How are particles arranged in a solid?

  In a solid, particles are tightly packed in a regular structure.
• How are particles arranged in a liquid?

  In a liquid, particles are tightly packed but free to move past each other.
• How are particles arranged in a gas?

  In a gas, particles are spread out and move randomly.
• What happens to density when the state of a material changes?

  • Changing the state of a material will change its density.
  • There is little difference between the density of a liquid and its corresponding solid.
  • Gases have the same mass but take up a larger volume, making them less dense.
• Why is a piece of iron heavier than a piece of aluminium with the same dimensions?

  A piece of iron is heavier because the atoms are more closely packed.
• What is matter made up of?

  Matter is made up of small particles called atoms.
• How can scientists measure how tightly packed the particles are in a material?

  Scientists can measure how tightly packed the particles are by measuring the mass of a certain volume of the material.
• How can atoms exist?

  Atoms can exist on their own or together as molecules.
• What is the density of iron in grams per cubic centimetre (g/cm³)?

  The density of iron is 7.8 g/cm³.
• How small are atoms?

  Atoms are very small, with around 100,000,000 of them measuring 1 centimetre end to end.
• What is density in terms of materials?

  • Density is a measure of compactness.
  • It is the ratio of mass to volume.
  • Usually measured in kilograms per metre cubed (kg/m³) or grams per centimetre cubed (g/cm³).
• What is the density of ice in grams per cubic centimetre (g/cm³)?

  The density of ice is 0.98 g/cm³.
• What is volume in the context of three-dimensional shapes?

  The volume is a measure of the amount of space or capacity a shape occupies.
• What is the density of water in grams per cubic centimetre (g/cm³)?

  The density of water is 1 g/cm³.
• What is the volume of an average can of fizzy drink?

  The volume of an average can of fizzy drink is 330 ml.
• What is the density of air in grams per cubic centimetre (g/cm³)?

  The density of air is 0.00129 g/cm³.
• How do you calculate the volume of a regular-shaped object?

  • Use a ruler to measure dimensions.
  • Apply the appropriate equation based on the shape:
  • Cube: \(lwh\)
  • Sphere: \(\frac{4}{3} \pi \left(\frac{d}{2}\right)^3\)
  • Cylinder: \(\pi \left(\frac{d}{2}\right)^2 l\)
  • Cone: \(\pi \left(\frac{d}{2}\right)^2 \frac{l}{3}\)
• How is density calculated?

  • Density can be calculated using the equation: $density =$$\frac{mass}{volume}$ or $p=$$\frac{m}{V}$.
  • Density (p) is measured in kilograms per metre cubed (kg/m³).
  • Mass (m) is measured in kilograms (kg).
  • Volume (V) is measured in metres cubed (m³).
• What is the density of a material if 0.45 cubic metres (m³) has a mass of 0.2 kg?

  The density is $0.44~kg/m^{3}$.
• What is the equation for the volume of a cube?

  The volume of a cube is calculated using the equation \(lwh\).
• What is the density of a metal if 4 cubic metres (m³) has a mass of 2,200 kg?

  The density is $550~kg/m^3$.
• What is the equation for the volume of a sphere?

  The volume of a sphere is calculated using the equation \(\frac{4}{3} \pi \left(\frac{d}{2}\right)^3\).
• What are the standard units for density, mass, and volume?

  • Standard unit for mass: kilograms (kg)
  • Standard unit for volume: cubic metres (m³)
  • In laboratory situations, mass is often in grams (g) and volume in cubic centimetres (cm³).
• What is the equation for the volume of a cylinder?

  The volume of a cylinder is calculated using the equation \(\pi \left(\frac{d}{2}\right)^2 l\).
• What is the equation for the volume of a cone?

  The volume of a cone is calculated using the equation \(\pi \left(\frac{d}{2}\right)^2 \frac{l}{3}\).
• How do you measure the volume of an irregular shape?

  • Use a displacement can.
  • Fill the can with water up to a narrow spout.
  • Place the irregular solid in the can.
  • Measure the volume of the displaced water, which equals the volume of the solid.
• What is the density of a material if 15 cm³ has a mass of 30 g?

  The density is $2~g/cm^3$.
• How do you convert between kg/m³ and g/cm³?

  • To convert from kg/m³ to g/cm³, divide by 1,000.
  • To convert from g/cm³ to kg/m³, multiply by 1,000.
• What is the density of aluminium in grams per cubic centimetre (g/cm³)?

  The density of aluminium is 2.7 g/cm³.
• What is a displacement can used for?

  A displacement can is used to measure the volume of an irregular solid.
• What is the density of lead in grams per cubic centimetre (g/cm³)?

  The density of lead is 11.6 g/cm³.
• What happens when an irregular object is placed in a displacement can?

  The water level rises, and the displaced water's volume equals the volume of the object.