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Gravity
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- 2. PRESENTATION BY ANJALI.T PHYSICAL SCIENCE 13386001 ST.THOMAS TRAINING COLLEGE,MUKKOLAYKKAL
- 3. GUESS THE WEIGHTOF THE CHOCOLATE BAR REMEMBER TO INCLUDE UNIT OF MEASUREMENT
- 4. •It'1.5 N butwhy?
- 5. • Mass isa measure of how much matter or particles an object has. • Weight is a measure of how strongly gravity pulls on that matter • So if you were to travel to the moon, where gravity is weaker, what would change? • Just remember that the weight of an object depends on where it is, while its mass stays the same.
- 6. • I havetwo bags, both the same shape and size. One bag contains feathers and the other contains bricks. Which is heavier?.. • Which is heavier a ton of bricks or a ton of feathers?..
- 7. Gravity – whatis it? • is an attractive force between objects with mass. • Gravity acts on the Earth by ppuulllliinngg objects towards its centre. • An object with heavier mass has a stronger gravitational pull = has a heavier weight.
- 8. Gravity – whatis it? Which aarrrrooww iiss ppooiinnttiinngg tthhee wwrroonngg wwaayy??
- 9. Gravity – whatis it? Yes, it’s this one
- 10. Who discovered it? • It was Sir Isaac Newton that ‘worked-out’ gravity. • 1643 – 1727 • He was the greatest English mathematician of his generation. His work on optics and gravitation make him one of the greatest scientists the world has known.
- 11. Who discovered it? The story goes that he was sitting under an apple tree and an apple fell onto his head. He went to explore why it fell down and came up with a theory and mathematical equation.. He named it GRAVITY.
- 12. How do wemeasure it? • We measure all forces in Newton. The effect of gravity gives us our weight - so our weight should always be in Newton. • It is mass which is measured in kilograms. Newtonmeter (also called Forcemeter, Spring balance, and Pullmeter)
- 14. Gravity on Earth causes this man to accelerate downwards. Its effect is the same everywhere.
- 15. WEIGHT = MASSx GRAVITY (N) (kg)
- 17. The astronaut hasa mass of 80kg but when will he weigh more? on the Moon on the Earth Gravity = 1.5 Gravity = 10 Weight = 80 x1.5 Weight = Weight = 80 x 10 120 N Weight = 800 N
- 18. NAME OF OBJECT MASS (grams) To convert in to KG we (÷1000) MASS (Kilograms) The pull ofGravity is 10 so we (x10) WEIGHT (Newtons) A packet of crisps 125g A car 1500kg 10 bags of sugar 10,000g A football 400g A mobile phone 250N
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Editor's Notes
- #8 Teacher notes: Talk about man on the moon – did he walk normally? (No) It was the gravity that made him so light. Why didn’t the space rocket ‘fly’ off too? (It’s mass was much greater than a man!) Going to the moon is one sure way to lose weight! You might want to go further and talk about walking on Jupiter (has a much greater mass) and gravitational pull is stronger, so walking would be impossible. We would be much heavier on Jupiter! We might look very different if our planet’s mass was much greater – we would have had to evolve to cope with a much stronger gravitational pull.. maybe we’d be short and squat!
- #9 Teacher notes: Talk about man on the moon – did he walk normally? (No) It was the gravity that made him so light. Why didn’t the space rocket ‘fly’ off too? (It’s mass was much greater than a man!) Going to the moon is one sure way to lose weight! You might want to go further and talk about walking on Jupiter (has a much greater mass) and gravitational pull is stronger, so walking would be impossible. We would be much heavier on Jupiter! We might look very different if our planet’s mass was much greater – we would have had to evolve to cope with a much stronger gravitational pull.. maybe we’d be short and squat!
- #10 Teacher notes: Talk about man on the moon – did he walk normally? (No) It was the gravity that made him so light. Why didn’t the space rocket ‘fly’ off too? (It’s mass was much greater than a man!) Going to the moon is one sure way to lose weight! You might want to go further and talk about walking on Jupiter (has a much greater mass) and gravitational pull is stronger, so walking would be impossible. We would be much heavier on Jupiter! We might look very different if our planet’s mass was much greater – we would have had to evolve to cope with a much stronger gravitational pull.. maybe we’d be short and squat!
- #11 Teacher Notes Although Newton and major scientists aren’t what we have to teach – it’s general knowledge. However, it’s also good to teach as another scientist (Einstein) did turn up in the 2006 SATs. Obviously, gravity wasn’t ‘discovered’ but it was Newton that formulated ideas and named it so. The apple story is not formally recorded and may be apocryphal, but it aids the memory nonetheless (and is fun).
- #12 Teacher Notes Although Newton and major scientists aren’t what we have to teach – it’s general knowledge. However, it’s also good to teach as another scientist (Einstein) did turn up in the 2006 SATs. Obviously, gravity wasn’t ‘discovered’ but it was Newton that formulated ideas and named it so. The apple story is not formally recorded and may be apocryphal, but it aids the memory nonetheless (and is fun).