To Determine the Density of a Solid (Class 9 Physics Practical)
To find the density of a solid object by measuring its mass and volume using standard measuring instruments.
TL;DR: To find the density of a solid object by measuring its mass and volume using standard measuring instruments.
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Aim: To find the density of a solid object by measuring its mass and volume using standard measuring instruments.
Materials Required
- Solid object (stone, metal cube, or irregular solid)
- Electronic balance
- Measuring cylinder
- Water
- Thread
- Beaker
Theory
Density is defined as mass per unit volume: Density = Mass/Volume. For a regular solid, volume can be calculated using dimensions. For an irregular solid, volume is determined by water displacement method using the formula: Volume = Final water level - Initial water level.
Procedure
- Measure the mass of the solid object using an electronic balance and record it
- Fill a measuring cylinder with water up to a marked level (initial reading) and record it
- Tie the solid object with a thread and gently immerse it completely in the water
- Record the new water level (final reading) in the measuring cylinder
- Calculate the volume of the solid: Volume = Final reading - Initial reading
- Calculate density using: Density = Mass/Volume
- Repeat the measurement 3-4 times with the same object and find the average density
- Compare with known density values of the material
Observation
The mass of the solid is recorded as [value] grams. When immersed in water, the water level rises from [initial] mL to [final] mL. The volume of the solid is therefore [value] mL or cubic centimeters.
Result
The density of the solid is calculated as [value] g/cm³, which matches the known density for the material [name].
Precautions
- Ensure the object is completely immersed in water without splashing
- Read the water level at eye level to avoid parallax error
- Use a measuring cylinder of appropriate size for accurate reading
- Dry the object before weighing if necessary
- Use distilled water to avoid reading errors due to meniscus
Viva Questions
Define density.
Density is the mass of a substance per unit volume. It is expressed as g/cm³ or kg/m³.
Why is water displacement used for irregular solids?
For irregular solids, it is difficult to measure dimensions and calculate volume mathematically, so water displacement provides an easy method.
How does the density of different materials compare?
Different materials have different densities. For example, iron is denser than aluminum, and both are denser than water.
What is the density of water?
The density of water is 1 g/cm³ or 1000 kg/m³.
More Class 9 Physics Practicals
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- To Verify Ohm's Law
- To Find Resistance Using a Metre Bridge
- To Study the Laws of Reflection
- To Verify the Laws of Refraction (Glass Slab)
- To Study a Simple Pendulum and Find the Acceleration Due to Gravity (g)
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