What is IT?

Newton did IT while the apple fell from the tree.
Pascal did IT under pressure.
Hertz did IT frequently.
Faraday did IT while rotating.
Maxwell did IT under magnetism and electricity.
Boltzmann did IT randomly.
Thompson did IT while shooting particles.
Rutherford did IT with an atomic model.
Bohr did IT excitedly.
Heisenberg did IT abstractly.
Schrodinger did IT realistically.
Pauli did IT but excluded his friends.
Feynmann did IT jokingly.