1. Atomic Physics
Uses of radiation

2. Probing matter
At the begging of the 20th century, most physicist believed that atoms themselves are made of smaller particles, with charges. But they had no way of showing this. Rutherford in 1911 used alpha particles to shoot at gold foil. A zinc sulfide detector was moved around the foil to detect the directions the alpha particles went after striking the foil.

4. Discovery from the Experiment

5. Conclusions from Experiment

6. Conclusions from Experiment

7. Conclusions from Experiment

8. Further Research
Their experiment was further using higher energy alpha particles. Not only did they see the results of the repulsive electrostatic force, but also a strong attractive force that appeared only over a very short range.
This become know as the strong nuclear force, one of the fundamental forces of the Universe. It holds the nucleus of atoms together.

9. Gold Foil Experiment

10. Atomic Forces Particles experience forces to keep its structure.
Gravitational forces act on all masses, even particles to each other
Electrostatic force that acts between charges particles. Its repulsive force is 10^36 times greater then the gravitational force between the protons.
Strong force acts between nucleons, the protons and neutrons in the nucleus, its an attractive force, does not reach outside the nucleus onto the electrons, very short range

11. Example Here is a hydrogen atom with an electron orbiting the nucleus.
a) State, for the forces acting on the electron and proton
Their nature
Their direction
b) Explain why a strong force does not act on the electron or proton

12. Classwork
State the forces acting on the nucleons of a helium nucleus