AIM

To establish the relation between the loss in weight of solid when fully immersed in

tap water

strongly salty water, with the weight of water displaced by it by taking at least two different solids.

APPARATUS REQUIRED

A spring balance, a clamp stand, two different solids, such as metallic brass bob and rectangular block, overflow can, tap water, strongly salty water, a strong thread and two empty beakers.

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THEORY

According to Archimedes’ principle, when a body is immersed in a liquid, completely or partially, it loses its weight. The loss in weight is equal to the weight of liquid displaced by the body.

The loss in weight of a body is due to the presence of upthrust which is equal to the weight of liquid displaced. Thus,

Loss in weight = Weight of body in air – Weight of body immersed in water

=W – W1

= Upthrust in water on the body

= Weight of liquid displaced.

PROCEDURE

CBSE Class 9 Science Practical Skills - Archimedes’ Principle 1

(A) Measurement for the apparent loss in weight of brass bob:

(a) Experiment with tap water:

Measure the weight of a solid, say a metallic ball in air by using spring balance as shown in Fig 3.1 and as per procedure explained in Experiment 2 of Term II.

Weigh the empty beakers using spring balance.

Set the spring balance, overflow can with tap water and beaker as shown in Fig 3.2.

Now, allow the bob to immerse completely in water in overflow’ can.

Note down the new position of pointer of the spring balance. This will give you the weight of the brass bob in tap water.

Weigh the beaker containing displaced water which is collected from the overflow can while immersing the bob in it completely.

Find the weight of displaced water by subtracting the reading of step (2) from step (6). The weight of liquid displaced is equal to the upthrust. Therefore, the weight of displaced water would be equal to the loss of weight in the brass bob.

Repeat the above steps two more times with the same brass bob after drying up completely. Tabulate your observations in Table A.

in simple words option B is the ans