An Explanation of Weightlessness in Space

In the Royal Institution video “What Is Weightlessness?” host Andrew Marmery explains what causes the sensation of weight on Earth and what really causes the feeling of weightlessness while travelling in space.

On one hand, we learn at school that weight is the force on an object due to gravity; on the other, there’s a more subtle understanding of weight as something we feel and discuss every day. How these two ideas fit together can cause some confusion, particularly when the idea of weightlessness and astronauts in orbit on the ISS is introduced.