NIOS Class 10 Science Activity 11.5 Gravitation

When we experienced that a mug filled with water appears to be heavier when it is lifted from the bottom of the bucket to above the surface of the water than the mug within the water in the bucket. Let’s understand why this happens.

 

NIOS Class 10 Science and Technology (212) Project File

This activity is based on the NIOS Class 10 science and technology (212) Chapter 11- Gravitation, Module 3- Moving Things.

Demonstration of Buoyant Force Activity

Aim

To observe the buoyant force acting on a wooden block

Materials Required

   1.  A large wooden block

   2. A bucket/ tank with water

Procedure

We take a large wooden block and place it on the surface of the water in the bucket. We observe what happens.

 Now we push the block into the water with our hand and notice what happens.

Next, we push the block further down until it is completely immersed in water. Finally, we release the block and notice what happens.

Observation

We observe that

   1.  The wooden block floats when it is placed on the surface of water.

   2.  An upward push(force) is felt when the block is pressed into water.

   3. The block bounces back when it is released after immersion in the water.

Explanation

Water exerts an upward force on the object when it is placed in water. This upward force is called the buoyant force or upthrust.

When the buoyant force is greater than the weight of the object, then the object floats on water; otherwise, it sinks.

So, all objects experience buoyant force in liquids.

Conclusion

We can conclude that an upward force called buoyant force is experienced by an object when it is placed in water, and this force makes the object float or sink depending on the weight of the object.

   All Activities Solutions of Gravitation

    1.  Activity 11.1 Solutions

    2. Activity 11.2 Solutions

    3. Activity 11.3 Solutions

    4. Activity 11.4 Solutions

    5. Activity 11.5 Solutions

    6. Activity 11.6 Solutions

Frequently Asked Questions

   1. Why does the wooden block float on water?

Answer – Because the buoyant force exerted by water balances the weight of the block.

   2. Do all objects in water experience the same buoyant force?

Answer – No, the buoyant force depends on the volume of water displaced.

   3. What principle explains this activity?

Answer -  This activity explains “ Archimedes’ principle”.

 

   4. What is Archimedes' principle?

Answer – When a body is immersed fully or partially in a fluid, it experiences an upward force that is equal to the weight of the fluid displaced by it.