#### To study the characteristic of spirogyra/Agaricus, Moss, fern, Pinus (either with male or female cone) and an angiospermic plant - Science Practicals

Aim

To study the characteristic of spirogyra/Agaricus, Moss, fern, Pinus (either with male or female cone) and an angiospermic plant. Draw and give two identifying features of groups they belong to.

Theory

The mass of unit volume of a substance is called its density.
Density = Mass of the substance/Volume of substance
If D is density of a body of mass M and volume V, then D = M/V
In S.I. units density is expressed in kg/m3.
For example, Density of water is 1000 kg//m3
To determine the density of an object, we have to measure two quantity mass and volume.

Materials Required
A spring balance of appropriate range, a solid body (a piece of stone), thread, water and graduated cylinder of appropriate range.

Procedure

A. For determining mass 'Al' of the solid body by using a spring balance.

Step 1: A spring balance is taken of appropriate range.

Step 2: The number of divisions between two long graduation marks is found on the scale of the spring balance and find its least count.

Step 3: A thread is tied to the given solid body (a piece of stone) and suspended from the hook at the lower end of the spring balance. The reading of the pointer on the scale of the spring balance is noted. Let it be 'W'. Thus 'W' is the weight of the given solid body in g wt. Mass of the solid body is W grams. Thus, M = W×10-3 kg.

Step 4: The observations is repeated two more times.

B. For determining the volume of the given solid body by measuring cylinder

Step 1: A graduated cylinder of suitable range is taken and its least count noted down.

Step 2: Some water is poured into the cylinder and the initial level of water in the cylinder is note. The reading at the lower meniscus of water (P) is taken on the graduated cylinder. Let it be V1.

Step 3: Now, the solid is fully immersed in water without touching the side walls of the cylinder. The level of water rises. The reading at lower meniscus of water level (Q) on the graduated cylinder is noted. Let it be V2.

Step 4: The observations are repeated for two more times.

Precautions

1. The measuring cylinder must be dry and clean.

2. The scale of the spring balance should be adjusted to read zero initially.

3. Take the reading only when the body comes to rest.

4. Only the lower meniscus of the water level should be read.

5. The body should fully immerse in the water, the solid body should not touch the sides or base of the cylinder.

6. The solid piece should be wiped with a dry cloth before repeating the activity.

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