Pearls of Water

This is a visual way of illustrating the effects of gravitational acceleration. The demonstration separates the horizontal and vertical motion of a jet of water as it moves through the air.

As the horizontal motion of the water drops remains constant, this demonstrates that there are no horizontal forces acting on the drops (other than negligible air resistance). By contrast, the further along the trajectory you look, the greater the vertical displacement between adjacent drops. This means that the drops are speeding up in the downwards direction - they are accelerating and must have a force acting on them. This force is due to gravity.

This resource was produced following National Science & Engineering Week 2013, during which teachers and technicians nominated their favourite demonstrations to be turned into video resources with accompanying written guides.

This resource was funded by the Gatsby Charitable Foundation.