Density of Solid

Mass per unit volume is one method for describing a material's density. The lab can use a spring balance to determine the material's mass. The mass that was determined shall be referred to as weight per convention. If a solid has a regular geometric shape, its volume can be measured directly. Here, we will experiment to measure the density of a solid by measuring its mass and volume.

Table of Contents

• Aim

• Apparatus required

• Theory

• Result

• Precautions

Aim

The aim of this experiment is to determine the density of a solid, which will be denser than water. 

Apparatus Required

Spring balance, a beaker filled with water, a metal object, a measuring cylinder, string and a stand

Theory

The mass per unit volume of a substance is defined as the density of the substance. The formula for density is: 

\[Density = \dfrac{{Mass}}{{Volume}}\]. 

S.I. unit of density is \[Kg/{m^3}\]. The ratio of a density of a substance to the ratio of the density of reference (water, in our case) is defined as the Relative density of the substance. The difference between density and relative density is that the density is mass divided by volume (its unit is ${kg/m^3}$). In contrast, relative density is the density of a substance divided by the density of reference (it has no units).

The density of water is 1000\[Kg/{m^3}\]. So, if the density of the solid is less than the water, then the solids will float on the water, and if the density of the solid is more than the water, i.e., the solid is denser, the solid will sink in water.

Spring balance is used to measure the weight of a substance, and weight can be defined as the force on an object due to the earth's gravity.

Force = mass x acceleration, 

As weight is a force, so weight = mass x acceleration due to gravity, 

Weight = m x g

Procedure

1. Tie the metal object with a string and attach the string to the hook of the spring balance. Take the reading of spring balance before attaching a metal object. Write it down as ‘x’. Make sure it’s zero. This is called zero error.

2. Tie the spring balance to the stand or hold it in hand. Measure the weight of the object. Consider this weight as ‘WF’.

3. Pour water into a given measuring cylinder. And note down its initial volume as ‘V1’.

4. Now put the metal object in a measuring cylinder which contains water. Do not let the object touch the sides of the cylinder or base. The water level rises after putting metal objects in the cylinder. Now note down the increased volume in the measuring cylinder. Write this volume as ‘V2’.

5. Take some more readings and perform the calculations to find the density of a given metal object. 

Density of Solid 

Observations

1. An initial reading of spring balance x = 0

2. Weight of the metal object = W = WF – x 

3. Mass of metal object = M = WF/9.8 

4. Initial volume in measuring cylinder at P = V1

5. The final volume in the measuring cylinder at Q = V2

6. Volume of Metal object V = V2- V1 

Calculations 

${Density= {\dfrac{Mass (M)}{Volume(V)}}}$ = ……… (${kg/m^3}$)

Result

Density of Metal is ……………. (${kg/m^3}$)

Precautions

1. Make sure the spring balance reads zero initially.

2. Take all the readings of spring balance and measuring cylinder carefully such that your eyes are parallel to the reading.

3. Make sure that the metal object does not touch the sides of the cylinder.

Lab Manual Questions

1. Can you determine the density of any porous solid by using the spring balance and measuring cylinder setup?

Ans: We cannot find the density of porous solid using spring balance and measuring cylinder. Because the porous solid will absorb water, the mass of the solid will increase instead of decrease. This will affect the volume of water displaced.

2. How will the presence of air bubbles in the measuring cylinder affect the volume of the solid?

Ans: Air bubbles in liquid in the measuring cylinder will affect volume because air bubbles will occupy some space in the liquid, increasing the volume of the liquid.

3. What will happen to the density if we melt a metal cylinder and cast it in the shape of a cube? Give reason

Ans: Density will remain the same as the mass, and the volume of water displaced by the cylinder and cube will remain the same. So, the density will also remain the same.

4. At what temperature the density of water is maximum?

Ans: The density of water is maximum at 40C.

Viva Questions

1. Define density.

Ans: Density is mass divided by volume.

2. State SI unit of density.

Ans: SI unit of density is Kg/m3.

3. Define density and give its SI unit

Ans: We can define density as mass upon volume, SI unit is Kg/m3.

4. What is C.G.S unit of density?

Ans: C.G.S. unit of density is g/cm3.

5. What is relative density?

Ans: Relative density is the density of a substance divided by the density of reference.

6. What is the value of acceleration due to gravity?

Ans: 9.8m/s2

7. What is the difference in mass and weight?

Ans: Mass does not change with location but weight changes with a change in location.

8. What is the unit of relative density?

Ans: It is unitless.

9. What does spring balance measure?

Ans: Weight of body.

10. If we double the mass, what happens to density?

Ans: Density also doubles

Practice Based Questions

1. SI unit of Density is

1. N

2. g/cm3

3. kg/m3

4. m

Ans: c) kg/cm3

2. Formula of density is

1. ${Mass \times Volume}$

2. ${Mass/Volume}$

3. ${Mass \times Weight}$

4. ${Mass/Weight}$

Ans: b) ${Mass/Volume}$

3. Which of the following has the highest density?

1. Water

2. Ice

3. Oil

4. Iron

Ans: d) Iron

4. Relative density of water is

1. 1000

2. 100

3. 10

4. 1

Ans: d) 1

5. Two substances of relative densities d1 and d2 are mixed in the same volumes, then the relative density of the mixture becomes 4, and if mixed in the same masses, then the density of the mixture is 3. The values of d1 and d2 are _____ respectively

1. 6, 2

2. 4,2

3. 12, 3

4. 5, 6

Ans: a) 6, 2

6. What happens when we put ice in water?

1. Ice floats

2. Ice sinks

3. Ice floats partially and partially sinks

4. None of these

Ans: a) Ice floats

7. The body floats on water when its density is

1. More than water

2. Less than water

3. Equal to water

4. None of above

Ans: b) Less than water

8. If the mass of a body is halved

1. Density doubles

2. Density halves

3. Density remains same

4. None of these

Ans: b) Density halves

9. Density is

1. Directly proportional to mass

2. Directly proportional to volume

3. Inversely proportional to mass

4. Equal to Volume

Ans: a) Directly proportional to mass

10. Weight =

1. ${m \times g}$

2. ${m \times v}$

3. ${v \times g}$

4. ${v \times m}$

Ans: a) ${m \times g}$

Conclusion

In this experiment, we found the density value of a given solid using a spring balance and measuring cylinder. The density of a substance is mass divided by volume. When we put an object in water, the volume of water increases. This increase in volume is equal to the volume of the object.