Question map
If some object is weighed when submerged in water, what will happen to its weight compared to its weight in air ?
Explanation
When an object is submerged in water, it experiences an upward force known as upthrust or buoyant force [2]. According to Archimedes' Principle, this buoyant force is equal to the weight of the liquid displaced by the object [1]. This upward force acts in the opposite direction to the force of gravity (the object's actual weight). Consequently, the measured weight of the object decreases while it is submerged [2]. This reduced measurement is referred to as the 'apparent weight' [1]. The apparent weight is calculated as the difference between the actual weight in air and the buoyant force exerted by the fluid [1]. Therefore, any object submerged in a fluid will appear to weigh less than its true weight in air due to this constant upward pressure exerted by the surrounding water.
Sources
- [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > Snapshots > p. 77
- [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > A step further > p. 76