Our brain’s weight is around 1.6-1.8kg, still we don\’t feel it heavy. Our brain has a fluid called as Cerebrospinal Fluid (CSF) which performs several functions in our brain like acting as shock absorber, helping in excretion e.t.c. Among these the most important function is providing buoyancy/ up thrust force to the brain. Therefore, the amount of weight given by the brain to the trunk of our body, the CSF exerts the same up thrust force against it. This is how CSF helps in maintaining the equilibrium and we don\’t feel our brain heavy.