Buoyancy is a/an

Buoyancy, also known as upthrust, is defined as the net upward force exerted by a fluid on an object that is partially or fully immersed in it [1][2]. According to Archimedes' principle, this upward force is equal to the weight of the fluid displaced by the object [1]. The physical origin of buoyancy lies in the pressure difference within the fluid; since pressure increases with depth, the upward force acting on the bottom of a submerged object is greater than the downward force acting on its top [3]. This resulting net force acts in the upward direction, opposing the downward force of gravity (weight) [1]. If this buoyant force is greater than or equal to the object's weight, the object will float; otherwise, it sinks [1]. Therefore, buoyancy is fundamentally characterized as an upward force rather than just pressure or a downward action.

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > Activity 5.13: Let us investigate > p. 76
2. [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > Snapshots > p. 77
3. [3] https://www.grc.nasa.gov/www/k-12/WindTunnel/Activities/buoy_Archimedes.html