Match the words below with their definitions. There are four extra words.

Write one word in each gap.

research, inventor, machine, permission, crowd, experiment, field, heat, height, power

The act of allowing someone to do something. (n) [ ]

To study a subject in detail. (v) [ ]

The distance from the top to the bottom of something. (n) [ ]

Physical strength or electricity. (n) [ ]

A large group of people who have come together. (n) [ ]

A test that is done in order to learn something or to prove a theory. (n) [ ]