A Ppt explaining the effects of gravity and what causes it. The target audience is 5th graders.

1. Gravity:the
phenomenon
that keeps
our feet on
the ground:
By Moira Whitehouse PhD
Modified by Mrs. Burch for 5th grade

2. What is gravity?

3. You will sometimes hear people say
that gravity is a force.
What is the scientific definition of
force?

4. Force is the energy that causes an
object to be pushed or pulled.

5. Gravity pulls.
Every object has this gravitational pull.
So every object pulls on every other
object.
The more mass an object has, the
harder it pulls.

6. Can you fill in the blanks…?

7. Gravity ____.
Every object has this gravitational pull.
So every object pulls on every other
object.
The more mass an object has, the
harder it pulls.

8. Gravity pulls.
Every _____ has this gravitational ___.
So every object pulls on every other
object.
The more mass an object has, the
harder it pulls.

9. Gravity pulls.
Every object has this gravitational pull.
So every object ____ on every other
_____.
The more mass an object has, the
harder it pulls.

10. Gravity pulls.
Every object has this gravitational pull.
So every object pulls on every other
object.
The more ____ an object has, the
harder it pulls.

11. Gravity pulls.
Every object has this gravitational pull.
So every object pulls on every other
object.
The more mass an object has, the
harder it pulls.

12. We will use two hypothetical planets for our
example. Both the blue and green planets
are pulling on each other.
Which one pulls harder?

13. This should help us see that the more mass
an object has the stronger its gravity.
EarthMoon
The Earth has much more mass than the Moon, so it pulls much
harder. So much harder that the Moon is held in an orbit around
the Earth as though by some magically strong string.

14. But, the Moon’s gravity is also pulling on the
Earth. So hard, that the oceans swell toward the
Moon wherever it passes. We call this high tide.

15. Let’s think about gravity on our favorite little
planet, Earth.

16. Gravity on Earth pulls everything toward
its center.

17. That’s why there is
no top or bottom
and no one falls
off.

18. If you dug a hole
right through the
Earth and fell in,
how far would
you fall?

19. As soon as you passed it, you
would be pulled
back towards the
center.
You’d fall into the hole and shoot right past
the center because you would be going so
fast.
So you
would bounce back
and forth like a
bungee jumper till
you finally stopped
at the center.

20. On Earth it appears that not
everything falls to the ground at the
same rate. It seems to us that things
with less mass or weight (e.g. feathers)
fall slower than things with more mass
or weight (e.g. rocks).

21. This is a misconception!
As demonstrated by
Galileo in the 1500’s, all
objects in a vacuum fall at
the same rate, regardless
of mass.

22. Lighter objects on Earth fall slower due
to our atmosphere which slows their
descent.

23. On the Moon, an astronaut dropped a
feather and a hammer.
Since there is no atmosphere on the
Moon the feather and the hammer hit
the ground at the same time.

24. https://youtu.be/5C5_dOEyAfk
Watch this video of the astronaut dropping a hammer and feather
at the same time.

25. Demo dropping book and paper.

26. The weight of an object is a measure of
how hard gravity pulls on it.
However, the amount of gravity on each
planet differs. The Moon has only one-sixth
as much gravity as the earth. Consequently,
on the moon, you would weigh only one-
sixth of what you weigh on Earth.

27. This boy weighs
60 pounds on
Earth.

28. On the Moon he
would only weigh
10 pounds.

29. Since each planet has a
different amount of
gravity, this boy’s
weight would change
each time he went to
another planet.

34. On Jupiter,
this would be
like carrying
an extra 100
pounds
around on
your back all
day.

35. The farther an object is from the center of
a planet, the weaker the force of gravity.
So, would this apple weigh more in some
place like Death Valley or on top of a very
high mountain?

36. Weight of a one pound apple heading out
to space.
Apple
weighs
1 lb
here
Apple
weighs
1/4 lb
here
Apple
weighs
1/9 lb
here
Apple
weighs
1/16 lb
here

37. What causes gravity?
The great Sir Isaac Newton
couldn’t answer that one.
What Newton DID know is that it pulls on
everything in the universe.

38. For thousands of years, no one knew
what causes gravity. It wasn’t until the
1950’s that we finally had a scientist
who could explain it.
Can you guess who that scientist was?

39. It was Albert Einstein.

40. Einstein proposed his space-time
continuum theory.

41. His theory states that time and space
are one and the same.
Space + time = spacetime

42. The Universe is 3 dimensional, but to
understand his theory, picture a 2
dimensional piece of fabric.
Now, watch this video to see how this
spacetime continuum affects planets
and creates what we call “gravity”.
https://youtu.be/MTY1Kje0yLg

43. So, is it correct to say that gravity is
a force?

44. Technically, the answer is “no”. Gravity
is not a force.
If it’s not a force, then what is it?

45. Answer: Gravity is the effect of
massive objects warping the
spacetime continuum.
The more massive the object, the
more it warps this fabric.

46. Thank you, Albert Einstein!