Understanding Volume, Mass, Density, and Material Properties

Volume, Mass, and Density

Measuring Volume

Volume is measured in three dimensions: length, width, and height. Different methods are used for different states of matter:

• Liquids: Pour the liquid into a burette and read the measurement.
• Solids:
  • Regular shapes: length x width x height
  • Irregular shapes: Use the immersion method. Fill a burette halfway and carefully submerge the solid. The difference in water levels represents the volume of the solid.
• Gases: Fill a test tube completely with water. Invert the test tube into a water-filled container. Introduce the gas into the inverted test tube. The volume of gas collected displaces an equal volume of water, which can be measured.

Factors Affecting Volume

• Temperature: Volume increases with increasing temperature and decreases with decreasing temperature.
• Pressure: Volume decreases with increasing pressure and increases with decreasing pressure.

Measuring Mass

• Solids: Use a balance. Place the material on one side and add weights to the other side until balanced.
• Liquids: Pour the liquid into a burette and measure the volume. Knowing the density, you can calculate the mass.
• Gases: Calculate the mass of an empty balloon, inflate it with the gas, and measure the mass again. The difference is the mass of the gas.

Elasticity

Elasticity is the property of a material to deform under force and return to its original shape when the force is removed. Factors affecting elasticity include the material's strength, thickness, and composition.

Weight and Gravity

Weight = mass x gravity. Gravity is the force exerted by a planet on objects on its surface. Larger planets have stronger gravitational pulls. Larger objects experience a stronger gravitational force.

One newton is the force required to support a mass of approximately 100 grams on Earth.

Density

Gases occupy space and can change volume more easily than solids and liquids.

Density = Mass / Volume (g/cm³ or kg/m³)

Examples of densities:

• Water: 1.00 g/cm³
• Ethyl alcohol: 0.79 g/cm³
• Polystyrene: 0.01-0.015 g/cm³
• Cork: 0.20-0.24 g/cm³
• Iron: 7.8 g/cm³
• Copper: 8.9 g/cm³
• Gold: 19.3 g/cm³
• Methane: 0.0007 g/cm³
• Air: 0.0013 g/cm³
• Butane: 0.0026 g/cm³

Materials with a density greater than 1 g/cm³ sink in water, while those with a density less than 1 g/cm³ float.

Other Material Properties

• Solubility: The amount of a substance that can dissolve in 100 grams of water.
• Boiling Point: The temperature at which a substance changes from a liquid to a gas.
• Melting Point: The temperature at which a substance changes from a solid to a liquid.
• Tenacity: The ability of a material to withstand impact without breaking (opposite of fragility).
• Hardness: The resistance of a material to scratching.
• Thermal Conductivity: The ability of a material to transmit heat.
• Electrical Conductivity: The ability of a material to transmit electric current.
• Surface Tension: The resistance of a liquid's surface to penetration. This explains why cold air sinks and hot air rises.