Gravity | Silly Science Trick

Put a nickel on top of a quarter. Or, use whatever coins you have with the top one smaller than the bottom one. Hold them above your other hand. Drop them. They will rotate and reverse places. Get the distance just right and they will land softly in your lower hand. Great party trick. 🙂

I used my Samsung Galaxy s5 to film this at 1/8 speed. YouTube allowed me to trim out some dead time and shorten the video. It also did some minor enhancements to lighting and color.

After a year of using the phone, it was time to try some unused features. I am not an avid phone user.


28 thoughts on “Gravity | Silly Science Trick

  1. I suppose this refers specifically to Newton’s 2nd Law: the acceleration of an object depends directly upon the net force acting upon the object, and inversely upon the mass of the object. Is this referring to when the mass of an object is increased, the acceleration of the object is therefore decreased?

    • After I asked this, I read:
      ” Newtonian mechanics is exactly revealed to be an approximation to reality, valid to great accuracy at lower speeds. As the relevant speeds increase toward the speed of light, acceleration no longer follows classical equations. As speeds approach that of light, the acceleration produced by a given force decreases, becoming infinitesimally small as light speed is approached; an object with mass can approach this speed asymptotically, but never reach it.

      Unless the state of motion of an object is known, it is totally impossible to distinguish whether an observed force is due to gravity or to acceleration—gravity and inertial acceleration have identical effects. Albert Einstein called this the principle of equivalence, and said that only observers who feel no force at all—including the force of gravity—are justified in concluding that they are not accelerating.”-

      Is why this coin trick works, right?

      • When the coins are released, they come free from one of my fingers before the other one. That imparts a rotation.

        I put my lower hand at a distance to allow for 1/2 of a rotation by the time they reach it. That I learned from experience.

    • Yes. Suppose you have a small truck with a weak engine. Step on the gas full throttle. You get a certain amount of acceleration.

      Fill the truck with sand or gravel and step on the gas full throttle again. You will get much less acceleration. Double the mass. Half the acceleration. You understand that well.

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