Required Practical: Determining Density Flashcards

All 6 cards in this deck

What are the steps to determine the density of a regularly shaped solid?

e.g. a block $2$ cm $\times$ $3$ cm $\times$ $5$ cm of mass $60$ g

1. Measure the dimensions with a ruler and calculate the volume: $2 \times 3 \times 5 = 30$ cm$^3$.
2. Measure the mass on a balance: $60$ g.
3. Density $= \dfrac{m}{V} = \dfrac{60}{30} = 2$ g/cm$^3$.

What are the steps to find the density of an irregular solid by displacement?

e.g. a small stone

1. Measure the mass of the stone on a balance.
2. Fill a displacement (eureka) can to the spout, lower the stone in on thin string and collect the displaced water in a measuring cylinder — this volume is the stone's volume.
3. Density $= \dfrac{\text{mass}}{\text{volume}}$.

What are the steps to measure the density of a liquid?

e.g. some cooking oil

1. Measure the mass of an empty measuring cylinder on a balance.
2. Pour in the liquid, record its volume, then measure the mass again and subtract to get the liquid's mass.
3. Density $= \dfrac{\text{mass of liquid}}{\text{volume of liquid}}$.

Which apparatus should be used to measure a small dimension, such as the diameter of a wire, more accurately than a ruler?

A micrometer or Vernier callipers.

Why should the measurements in a density experiment be repeated?

A mean can be calculated, which reduces the effect of random errors (and anomalies can be identified).

True or false? When an irregular solid is fully submerged in a displacement can, the volume of water displaced is equal to the volume of the solid.

True. A fully submerged object pushes aside its own volume of water, which is collected and measured in a measuring cylinder.