Introduction
In this experiment, we will determine the height of a floating body above the water as the salinity of the water increases.
According to Archimedes’ principle, the graph between the amount of salt added to water and the height of the object above water is a straight line.
Aim
To measure the height of a floating body above the water as the salinity increases.
Theory
1. Archimedes’ principle is the fundamental law of Fluid mechanics.
2. According to this law, when an object is partially or fully immersed in water, it will experience an upward force. This force is equal to the weight of the fluid which got displaced.
3. The formula for Archimedes’ principle is:
F = -⍴gV
Where F = buoyant force
⍴ = fluid density
g = acceleration due to gravity
V = fluid volume
Image Source: Metacentric Height
Requirements
1. Cylindrical Cork
2. Glass of Water
3. 100 grams of Salt
4. Rubber
5. Teaspoon
6. Few Coins
7. Ruler
8. Ballpoint Pen
Procedure
Step 1: Take a glass of water.
Step 2: Add 100 grams of salt to the water.
Step 3: Put the cork into the glass.
Step 4: Now, note down your measurement in a notebook.
Observation
1. We have obtained the measurement of the height of the cork above the water and the added salt.
2. Graph obtained confirms the hypothesis.
Result
1. From the experiment, we find that the height of floating objects increases with increased salinity.
2. We have also found that the drop in salinity of water when a boat laden with fish returns into the water from the estuary can contribute to the drowning of boats.
3. The variation in the boat’s height before and after the boat is loaded in the estuary is equal to that in freshwater. This factor can be used to avoid accidents.
Source of Error
The possibility of air bubbles being attached to the object and the lack of precision in measurement can introduce some errors in the experiment. And due to this, some points did not exactly fall on the graph.
Precautions
1. Take the measurement accurately.
2. Absence of air bubbles from the object.
Conclusion
By gradually increasing the water salinity in a beaker and observing the height of the floating cork above water, the variation in the height of the boat with varying salinity of estuary water was stimulated,
VIVA Questions With Answers
Q.1 What was the aim of your experiment?
ANS. To measure the height of a floating body above the water as the salinity increases.
Q.2 Who invented Archimedes’ principle?
ANS. This law was given by Archimedes, who lived in Syracuse, Sicily (Italy)
Q.3 What do you understand about Archimedes’ principle?
ANS. According to this law, when an object is partially or fully immersed in water, it will experience an upward force. This force is equal to the weight of the fluid which got displaced.
Q.4 What is the formula for Archimedes’ principle?
ANS. Fb = -⍴gV
Where F = buoyant force
⍴ = fluid density
g = acceleration due to gravity
V = fluid volume
Q.5 What is the result of your experiment?
ANS. We find that by increasing the salinity of water, the height of floating objects above water increases.

Saquib Siddiqui is a Mechanical Engineer with expertise in science projects and experiments. Saquib’s work focuses on integrating scientific concepts with practical applications, making complex ideas accessible and exciting for learners of all ages. In addition to his practical work, Saquib has authored several articles, research papers, and educational materials.
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