2. Is gravity real - or does the Earth just suck? New End Primary School Tuesday 31 st March

3. Aristotle: for an object to continue moving there must be a force acting on it. It is understandable that he thought this was the case: Snap! In the seventeenth century Galileo argued that objects keep moving unless acted on by a force, for example friction. NEW END PRIMARY SCHOOLTUESDAY 31ST MARCH

4. It’s easy for us to imagine a situation where there is no friction. If Aristotle had been right, this would happen…

5. Newton later said: Objects continue to move in a state of constant velocity unless acted upon by an external net force. 1 ST LAW.

6. Newton Astronauts need to beware!

7. Newton also said: “Every action has an equal and opposite reaction.” - His 3rd law. Which explains why guns recoil and how rocket engines work.

8. NEW END PRIMARY SCHOOLTUESDAY 31ST MARCH PUSHPULL TWIST

9. NEW END PRIMARY SCHOOLTUESDAY 31ST MARCH move faster move slower change direction change shape stop moving start moving acceleration

10. NEW END PRIMARY SCHOOLTUESDAY 31ST MARCH

11. NEW END PRIMARY SCHOOLTUESDAY 31ST MARCH FORCE measured in NEWTONS Weight of an apple ≈ 1 Newton

12. NEW END PRIMARY SCHOOL TUESDAY 31ST MARCH Force of Earth acting on Box (weight) Force of Floor acting on Box Force from floor on box cancels gravity. If the floor vanished, the box would begin to fall.

13. NEW END PRIMARY SCHOOLTUESDAY 31ST MARCH Ping-pong ball Straw Try to suck the ball through the straw

14. NEW END PRIMARY SCHOOLTUESDAY 31ST MARCH The arrow represents the force of gravity

15. NEW END PRIMARY SCHOOLTUESDAY 31ST MARCH To stop gravity, we need an upward force. The ball does not fall when…. We can draw this by having arrows of the same weight. FORCES ARE BALANCED FORCES ARE NOT BALANCED ACCELERATION

16. NEW END PRIMARY SCHOOLTUESDAY 31ST MARCH

17. NEW END PRIMARY SCHOOLTUESDAY 31ST MARCH GRAVITY FRICTION AIR RESISTANCE THRUST

18. What happens when there are unbalanced forces acting on an object? Speed increases until drag grows to match drive. Speed decreases until drag matches drive again. For example when a driver who is travelling at constant speed accelerates or puts on the brakes. Accelerate: Brake: drivedrag

19. NEW END PRIMARY SCHOOLTUESDAY 31ST MARCH GRAVITY FRICTION AIR RESISTANCE THRUST MAGNETISM LIFT UPTHRUST ELECTRICITY

20. NEW END PRIMARY SCHOOLTUESDAY 31ST MARCH 1.When Isaac Newton discovered gravity, what knocked the sense in to him? 2.Which force keeps us on the Earth? Try sucking up the different balls with a straw. 3.Thurst is a powerful force that moves things forward. Which machines rely on clever design and thrust to keep them in the sky? Can you find any in the class room? Try throwing the machines! Who can get them furthest? 4.When two magnetic objects are bought near each other, they can attract or repel. Can you find any magnetic objects in the room? 5.Compasses work based on magnetism- they feel the magnetic field of the Earth. Point your compass to North! 6.When items move across rough surfaces, they lose energy and slow down due to friction. Try and find something that would cause a car to feel friction. 7.When objects fall to the ground they slow down due to air resistance. What do you think would have lots of air resistance? 8.When we turn a light switch, little electrons carry forces which cause material in the light bulb to heat up and emit light. Find where you think there is electricity in the room!