Bernoulli's theorem

Bernoulli's theorem states that in a moving ideal fluid the total energy remains constant. This energy is made up of the kinetic energy of motion, the potential energy due to gravity head of fluid, and the pressure energy.
The theorem indicates that when the pressure in a fluid decreases, the speed increases and vice versa. This explains, for example, how an aeroplane wing develops lift.
The theorem was developed by Daniel Bernoulli in 1738