Question

How can we measure the density of a piece of stone with a measuring cylinder and spring balance?
[4 marks]

Answer 1

For measuring the density of an irregular object, we need to measure its mass and its volume, which can be further divided to give density. [1 mark]

For measuring the mass we are using spring balance. Let's say the mass of the stone comes out to be 30 grams, as shown below. [0.5 marks]


For measuring the volume:

• First we will put some amount of liquid in the measuring cylinder and take the reading. Suppose this reading is 50 ml. [0.5 marks]
• Then we will put the irregular object in the cylinder. So the level of liquid will rise. So again we will take the reading. Here, it is 70 ml. [0.5 marks]

So the volume of the irregular object will be the difference between two readings, i.e., 70 ml - 50 ml = 20 ml. [0.5 marks]

Here, the mass of the stone is 30 grams and volume is 20 ml. The density of the stone will be given by:
Density = $\frac{mass}{volume}$


⇒ Density = $\frac{30g}{20ml}$ = 1.5 g/ml

In this way, we can calculate the density of an irregular object with the help of a measuring cylinder and spring balance. [1 mark]