Question

pre - lab assignment

1. give the order of the densities (from lowest to highest) of the substances shown in the sketch. wood floats on water but sinks in oil.
2. suggest a procedure for measuring the density of a liquid.
3. suggest a procedure for measuring the density of a solid that does not have a regular geometric shape.

Explanation:

Question 1

Step1: Analyze buoyancy and density

An object floats in a fluid if its density is less than the fluid's density, and sinks if its density is greater. Given wood floats on water (\(
ho_{wood} <
ho_{water}\)) and sinks in oil (\(
ho_{wood} >
ho_{oil}\)). Also, oil is above water, so \(
ho_{oil} <
ho_{water}\) (since less dense fluids float on more dense ones).

Step2: Order the densities

From the relationships: \(
ho_{oil} <
ho_{wood} <
ho_{water}\) (lowest to highest).

1. Measure mass of liquid: Use a balance to find the mass (\(m\)) of an empty graduated cylinder, then fill it with the liquid and measure the combined mass. Subtract to get the liquid's mass (\(m = m_{total} - m_{cylinder}\)).
2. Measure volume of liquid: Read the volume (\(V\)) of the liquid from the graduated cylinder's scale.
3. Calculate density: Use the formula \(

ho = \frac{m}{V}\) to find the liquid's density.

1. Measure mass of solid: Use a balance to find the solid’s mass (\(m\)).
2. Measure volume (water displacement): Fill a graduated cylinder with water (record initial volume \(V_1\)). Submerge the solid (ensure it’s fully immersed, no air bubbles), then record the final volume \(V_2\). The solid’s volume is \(V = V_2 - V_1\).
3. Calculate density: Use \(

ho = \frac{m}{V}\) to find the solid’s density.

Answer:

oil, wood, water

Question 2