Question 1: Define density in terms of mass and volume and state its SI unit.

Answer: Density is the mass per unit volume of a substance, measured in kilograms per cubic metre (kg/m^3).

Question 2: Explain why accurate measurement of volume is crucial in determining the density of an object.

Answer: Accurate volume measurement is essential because any error in volume directly affects the calculated density, leading to inaccurate results.

Question 1: Describe how the particle model explains the concept of density.

Answer: The particle model states that all matter is made up of particles. In denser materials, particles are packed more closely together, resulting in a higher mass per unit volume.

Question 2: List two safety precautions to consider when measuring the volume of irregular objects in this practical.

Answer: Using appropriate protective gloves to handle objects and ensuring the use of proper tools to avoid injury and ensure accurate measurements.

Question 1: A block of aluminium has a mass of 540 grams and a volume of 600 cm^3. Calculate its density in kg/m^3.

Answer: Density = mass / volume = (540 g) / (600 cm^3) = 0.9 g/cm^3 = 900 kg/m^3

Question 2: A student measures the density of a plastic cube as 1.2 g/cm^3. If the cube's mass is 24 grams, what is its volume in cm^3?

Answer: Volume = mass / density = 24 g / 1.2 g/cm^3 = 20 cm^3

Question 3: Explain why repeated measurements are important when determining the density of an object.

Answer: Repeated measurements help identify any anomalies or errors, ensuring greater accuracy and reliability of the density value.

Question 1: Identify at least three variables that could affect the accuracy of measuring the volume of an irregular object.

Answer: Water temperature (expansion), measurement technique (parallax error), and the precision of measuring equipment.

Question 2: Describe a safe method for measuring the volume of an irregular object using water displacement.

Answer: Place the object in a graduated container filled with water, ensuring it is fully submerged without splashing. Record the initial water level, then the level after submerging the object. Use the difference to find the volume, taking care to avoid spilling or splashes that can lead to inaccurate readings.

Question 1: A manufacturer needs to ensure that their aluminium components have a density within a specified range. If a component has a measured density of 2.7 g/cm^3, what could be inferred about its material quality?

Answer: Since the typical density of aluminium is about 2.7 g/cm^3, the component likely has the correct material quality and composition.

Question 2: Explain how the particle model supports the understanding of why density increases when a substance is compressed.

Answer: According to the particle model, increasing pressure compresses particles closer together, reducing the space between them. This increases the number of particles in a given volume, raising the mass per unit volume, and thus increasing the density.