# The Magic of Gravity

Bring Science Home: Activity 2

Observations and results
Why do you think the coin acted differently when you pulled the loop off slowly and when you swiped the loop away quickly?

The coin isn't acting out—it's obeying the laws of physics. When the loop it is resting or is pushed over slowly, it stays with the loop longer because friction helps keep it there. Then gravity eventually takes over and the coin tumbles down to the counter. But when the paper surface it has been resting on is swiped out from under it quickly, the friction doesn't have a chance to pull it along. Instead, the coin, which was at rest, has nowhere to go but straight down with the force of gravity.

Share your coin drop observations and results! Leave a comment below or share your photos and feedback on Scientific American's Facebook page.

Cleanup
Pour out the water, being careful not to lose any coins down the drain. Recycle or reuse your container.

More to explore
"What's the real story with Newton and the apple? See for yourself" from Scientific American
"How Much Momentum Does It Take to Stop a Running Back?" from Scientific American
"Newton's First Law" overview from NASA's Kid's Page
"Newton's Laws of Motion" overview from TeacherTECH
Gravity Is a Mystery by Franklyn M. Branley, ages 4–8
The Everything Kids' Science Experiments Book: Boil ice, float water, measure gravity—challenge the world around you! by Tom Robinson, ages 9–12

Up next…
Bend Water with Static Electricity

What you'll need
•    Three small Styrofoam cups (alternatively, you can use two paper cups to hold the water and an inflated balloon to provide the static charge)
•    Toothpick
•    Water
•    Someone with a head of clean, dry hair

Rights & Permissions

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1. 1. StephenSouthamptonUK 12:26 PM 5/3/11

"Have you ever seen a magician sweep a tablecloth quickly off a table and leave all the plates and glasses still in place? The trick isn't magic at all—it's science!"

Of course it is not science. Science may well try and explain it but it simply reality.

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2. 2. jesuspt 03:26 PM 5/3/11

Isn't science "real"??? And if it is not science, what "un-scientific" (but "real") explanation(s) would you propose?

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3. 3. Joe H 05:04 PM 5/3/11

"The quick move gives gravity a chance to overpower the friction—and demonstrate inertia."

Really? Do you read your own stuff?

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4. 4. sfrobbins 03:08 PM 5/4/11

Sorry, but gravity is too weak to "overpower" friction and demonstrate inertia in this case. Gravity's pull on a table cloth is enormously weak. What is being demonstrated is the difference between a strong (or weak) lateral force (the pull on the cloth), and the sliding coefficient of friction between the table cloth and; the plates, glasses and silverware. The lateral force must be very large compared to the friction, in order to work.

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5. 5. howardabrams in reply to StephenSouthamptonUK 04:39 PM 5/5/11

You're both right. Since science is the study of what's real, it is both reality and science.

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6. 6. ktperera 05:40 PM 5/8/11

Simple, gravity and therefore the weight of the coin hugs
the table cloth. Friction comes to play only when we pull on the table cloth. The friction force acting on the coin starts it to move across the table. But the table cloth is yanked so fast away from the coin the coins inertia cannot be overcome that fast, leaving the coin behind.

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7. 7. debu 10:46 AM 7/2/11

DURGADAS DATTA published a paper in ASTRONOMY.NET in year 2002 which has given a direction to new thinking to understand DARK ENERGY and DARK MATTER. The paper is--MISJUDGEMENTS BY NEWTON AND EINSTEIN. We live in a matter universe surrounded by antimatter universe on opposite entropy path. The common boundary is violent due to annihilation of matter and antimatter. GRAVITOETHERTONS or five god particles are produced and injected into our universe as DARK MATTER AND DARK ENERGY. EARLIER DAYS WE USED TO CALL IT ETHER. But our universe is non uniform field density of gravitoethertons soup and as such NEWTONS LAW WILL BE ...F=P.G.M.m/R.R WHERE P IS PERMEABILITY OF THIS SOUP. IN THIS NON UNIFORM UNIVERSE ,NEITHER NEWTON NOR EINSTEIN IS CORRECT. The five GOD PARTICLES are --four for four fundamental forces and one for mass creation. GRAVITY IS THE EFFECT OF MONOMAGNETIC COUPLING EFFECT OF GRAVITON--THE GRAVITY FORCE PARTICLE . So gravity is a push not pull. WE SEE CENTER OF EARTH / CENTER OF GALAXY ALL VERY HOT OR BLACKHOLE DUE TO FOCUS OF GRAVITOETHERTONS. DUE to monomagnetic coupling ,the earth , stars,galaxy ..all magnetic and we also live in magnetic universe. But we do not exactly see these god particles except their effect --gravity etc etc. SOON LHC AT GENEVA will/ may see these force particles . Our solar system may prove NEWTON AND EINSTEIN CORRECT but larger universe is where we will observe all laws and constants varying due to this non uniform universe and we have to be careful. I suggest NASA and LHC,CERN should jointly look into a different physics and try to develop string theory on spherical coordinates taking time as non dimensional. BALLOON INSIDE BALLOON THEORY OF MATTER AND ANTIMATTER UNIVERSE ON OPPOSITE ENTROPY ALSO SUGGESTS--that one universe will reach a tends to zero entropy and a big bounce will occur --again two universes on CP VIOLATION. Again matter universe will form on seeds of remaining big black holes escaped full evaporation to give a universe by chance tuned to laws for formation of lfe and again we will come back to ponder about universe--may be many many billion years after as this re cyclic is again and again for eternity. THIS IS THE ACTUAL RE CYCLIC MODEL NOT AS DESCRIBED BY DR.ROGER PENROSE. SO READ THE THEORIES OF DURGADAS DATTA TO UNDERSTAND PRESENT DAY ACCELERATING COSMOS WITH DARK ENERGY--MATTER--FLOW ETC ETC.

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8. 8. MattK 01:17 PM 2/29/12

debu got all of that from an elementary school demonstration of Newton's 1st Law of Motion? I can only imagine what debu might come up with if he or she were allowed to watch the Big Bang Theory on CBS on Thursday evenings.

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9. 9. StephenSouthamptonUK 01:27 PM 2/29/12

There seems to be a general misunderstand of what I was trying to say. Let me try again.

Science is a methodology which is used to make sense of reality. When we say something happened in a particular way because it is scientific then we are getting things in the wrong order.

So events happen and science attempts to understand it. Now the other way which is to say science made that happen that way which is clearly incorrect.

Indeed the scientific method is really all about being sceptical of itself.

o Use your experience
o Form a conjecture
o Deduce a prediction from that conjecture
o Test it.

So it understands doubt and we can never say that science understands something. At best we can say we have not found a test to make us doubt the given conjecture.

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10. 10. debu 09:26 AM 2/22/13

Matt knows better from a higher elementary laws of motion.We expect him to share some thoughts on gravity.

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