1. PHYSICS VS INTUITION

2. Physics vs Intuition What do we do in Physics? Observe the physical world and make models to help us understand how the different parts interact.

3. Physical Models Visual Models

4. Physical Models Mathematical Models

5. Physical Models Graphical Models

6. Physical Models Analogy

7. Why do we make these models? To make predictions Some examples Flashing lights Runners Beating sounds

8. Why not use intuition?  What happens when you get hit by a water canon?  We all know the answer but Physicists use laws to explain the answer

9. Newtons Laws of Motion Newtons 1st Law The water is changing it's velocity when it hits the people so there is an unbalanced force acting on the water Newtons 2nd Law The size of the force is equal to the rate of change of the momentum of the water. Newtons 3rd law There must be an equal and opposite force on the people

10. So the physicists can make a nice argument but don't tell us anything that we don't know.

11. The physicist can also make predictions.  If there is more water the rate of change of momentum will be bigger and therefore the force will be bigger.  We all knew that

12. When is intuition not enough? What happens when the rod below is subjected to two Forces?

13. When is intuition not enough?  What happens to the balloon when the car stops?

14. So what do I teach? How things work? No, a way of thinking How to use principles and laws to solve problems rather than intuition Non critical thinking?