504
5 amusing physical phenomena, which are easy to check at home
Surprise yourself and friends is easy, if you know how. Curious experiment can be carried out, for example, in your own kitchen, and each of us has everything you need for this.
We are in the Website view, that physics - a fascinating science, because it tells us about the amazing experiments. And not only it tells, but also gives you the opportunity to spend their own.
Focus with a stick Ask a friend to hold you to stick horizontally. Adding index fingers together, try to place them just below the center of gravity. Most likely, the cane will fall, because this way, immediately, the center of gravity you will not find.
But try to put your index fingers on the opposite ends of the stick, and then move them towards each other. As a result, the fingers meet just below the center of gravity. Always. Even if you move the fingers at different speeds, it is very slow or very fast, or put them asymmetrically.
How does it work?
Learn the answer
When the fingers are on the opposite ends of the sticks, large load is applied to the pin which is closer to the center of gravity of the cane. With growing pressure and friction: the finger, which is closer to the center of gravity, experiencing more friction than that on
.
Therefore, closer to the center of gravity of the finger for a while will not slip - always move only one finger, which is further away from the desired point. As soon as he will be closer to the center of gravity, the roles are reversed: moving the other finger comes. So they move alternately until then, until you get together closely under the center of gravity. The effect works, of course, not only with a cane, and with any stick.
Flip phone Have you ever tried to throw her phone so that the spinning? If you throw it long edge up and succeed: it will rotate in the same direction, clockwise or counterclockwise. If you throw him the "tip" up, then no problem, too, will not occur.
But if you try to throw it with the flat side up, it will not rotate strictly in one direction - instead of the phone gradually changes its direction of rotation of 180 °
.
Why is it so?
Learn the answer
We have three phone axis on which it can rotate, and consequently, three moments of inertia. The first and third axis - long and short - are stable, they have a maximum and minimum moments of inertia, respectively. The rotation on these axes is stable.
But when the phone is rotated by a second intermediate axis, in the case enters the so-called "theorem of a tennis racket." Math is hard.
But the point is that the object is rotated, not only in the intermediate axis, and the other two spatial axes at speeds on the order below. As a result of the impact of these minor movements of the main slope of the axis of rotation is gradually changing, and when the tilt angle reaches the critical rotation, the object makes a somersault - and voila
water and a plastic cup If you rub a plastic cup on the hair and bring it close to a stream running from the tap water, it is possible to reject the flow.
Why is the flow of water is attracted to the charged glass?
Learn the answer
Electrons from the hair by friction to move the cup and give it a negative charge. This charge pushes away the negatively charged electrons in the water, and they are moved to that part of the jet, which is furthest from the cup. Closer to the glass a water jet are positively charged particles and negatively charged glass pulls her to him.
Magnetic flakes Take a piece of your favorite cereal and toss in a bowl with water. Then bring to a strong magnet him and try to pull this piece.
flakes floating just behind the magnet. Cool, right? But what is the reason?
Learn the answer
Of course, in flakes contain iron - it is one of the trace elements needed by the body. But is not the case if you take a plastic Circuits, it will also be attracted to the magnet
.
The fact that water - diamagnetic. This means that when exposed to an external magnetic field, the water generates its own magnetic field. Fields "repel" each other, and on the surface image of the invisible to the naked eye "pit", which fails, or a piece of plastic flakes.
Tea rocket Take the tea bag and cut off the sealed side. Now, pour the tea. From bags fold a square column and put it on a plate. Now light the bag on top, evenly on all sides.
When the tea bag will burn down almost to the end (you will need only a few seconds), what is left, take off into the air like a rocket from him.
Why?
Learn answer
Hot air is less dense than cold air, so that the cold air pushes the warm up. And the ashes of the tea bag is so light that rushes up with a warm stream.
According to the materials: Vert Dider, Veritasium
Photos and preview: Veritasium
via www.youtube.com/watch?v=1Xp_imnO6WE&feature=youtu.be
