Find relative density of different objects in Floating bodies – Class 9 Science Experiment

Chapter Name: Floating bodies

Activity Name: Find relative density of different objects in Floating bodies

Activity Description:

Required Items:

• Overflow vessel
• 50ml measuring cylinder
• Weighing balance and weights or spring balance
• Rubber erasers
• Wooden blocks
• Glass slides
• Iron nails
• Plastic cubes
• Piece of aluminum sheet
• Glass marbles
• Stones
• Cork or any other objects (ensure volume is more than 20 cc and not hollow)

Step by Step Procedure:

1. Weigh the 50ml measuring cylinder and record its weight.
2. Weigh each object and record their respective weights in column 3 of Table 1.
3. Fill the overflow vessel with water until it starts dripping from its beak. Place the 50ml measuring cylinder under the beak.
4. Gently immerse the object into the overflow vessel, ensuring water does not splash out (refer to Figure 2). If the object is not fully immersed, use a pin to push it into the water.
5. Wait until the water flow stops, and the water collected in the 50ml cylinder stabilizes.
6. Weigh the cylinder with the water that overflowed and record the weight in column 4 of Table 1.
7. Subtract the weight of the measuring cylinder (recorded in step 1) from the weight obtained in step 6. This gives us the weight of water equal to the volume of the object (column 5 in Table 1).
8. To find the relative density of the object (column 6 in Table 1), divide the weight of the object (column 3) by the weight of an equal volume of water (column 5).
9. Repeat the procedure for all collected objects and find their respective relative densities.

Experiment Observations:

1. Record the weight of the measuring cylinder, weight of each object, weight of water overflowed, and calculate the relative density for each object in Table 1.

Precautions:

1. Ensure that the volume of the objects is more than 20 cc and that they are not hollow.
2. Be careful not to splash water while immersing objects into the overflow vessel.
3. Fully immerse the objects in water to get accurate results.
4. Use a pin to push in any partially immersed objects gently.

Lesson Learnt from Experiment:

This experiment helps us understand the concept of relative density and how it can be used to compare the density of different objects with respect to water. It also familiarizes students with the concept of buoyancy and why some objects float while others sink.