Creating a lightning effect in a particle system in Unity 5.5 (translation)

We'll start our fun experiments by calling lightning

Homemade zippers are best seen in the dark. The best days for calling lightning are clear and dry days. To carry out this fun experiment, you will need: a plastic comb, a wool sweater or rag, a metal door handle or door frame.

In order to call lightning, you need:

1. Rub the comb with quick movements on a woolen sweater or woolen rag for thirty seconds. The comb will be charged with electricity.

2. Bring the comb very, very close to the doorknob or frame without touching it. You will see a flash jumping between them, just like lightning running from a cloud to the ground.

Determining the type of fault

Having investigated the cause of the breakdown, it will be easier to correct it. If the zipper is missing one or more teeth, the problem is more difficult to solve. But it is possible to do this. Find an old lock with similar teeth and take the part from there, following these steps:

1. Remove one or more pieces from the old lock using an awl or a sharp-tipped knife.
2. Attach it to the lock you are repairing.

This is only a temporary measure. You will have to change the lock.

Before starting work, check the integrity of the fabric on which the teeth are attached. If it is damaged where the element is missing, then you are unlikely to be able to do anything.

If the zipper itself is not damaged, but the lock still does not work, determine the type of damage.

• The lock jams in certain areas. Fixing such a breakdown is not difficult: rub the part with paraffin or soap.
• If the zipper diverges, then press it from all sides.
• The runner jumped out. This damage is more difficult to fix. The repair method will depend on the type of broken lock.
• When moving, the dog does not connect the parts, but slides to the side. Try to repair the old one or buy the same runner at the store.

Before starting repairs, determine what type of lock your lock is.

Let's continue our fun experiments by blowing up an empty tin can

To carry out this physical experiment, we will need: an empty aluminum drink can with a ring opener, kitchen tongs, a large bowl or sink half filled with cold water, a tablespoon, a stove.

To make an empty can explode, you need to:

1. Fill a large bowl with cold water or fill the sink halfway.

2. Check that the tongs are holding the tin tightly.

3. Pour two tablespoons of water into the jar.

4. With the help of an adult, place the jar on the stove and boil water.

5. After steam has escaped from the can for twenty seconds, grab the can with tongs, palm facing up.

6. Quickly bring the jar to cold water, turn it upside down (very carefully so as not to drip boiling water on yourself) and lower the top of the jar just below the level of the cold water.

7. Look what happens!

The steam pushes the air out of the can. As the tin cools, the steam turns back into a very small amount of water. Air pressure from the outside of the can will compress it inwards. Without air inside the can to push outward on the walls, this pressure “explodes” the can.

Atmospheric pressure is much greater than you think - just watch how the can collapses!

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Laboratory experiments with atmospheric electricity make it possible to learn a lot, but mysteries still remain. Nikola Tesla's plasma lamp cannot be considered a model of ball lightning, although the inventor was probably driven by interest in this strange atmospheric phenomenon. It turned out that cold plasma in a rarefied medium in the presence of a rapidly varying electric field has little to do with it. Photo (SXC license): Jeff Hire

There has been a ball lightning workshop at the St. Petersburg Institute of Nuclear Physics for several years. Here a small installation was invented and created that reproduces with sufficient accuracy the natural process of the birth of lightning on a damp surface: there is a copper input that acts as a lightning rod, a quartz tube with an electrode, and an open surface of tap water. The role of the thunder cloud is a 600 µF capacitor bank, which can be charged up to 5.5 kV. This is a serious voltage - the slightest carelessness when working with it poses a mortal danger.

It was described in detail in an institute preprint dated March 24, 2004. The water in the polyethylene cup must be grounded; for this, a copper ring electrode is placed at the bottom. It is connected by an insulated copper busbar to the ground. The positive pole of the capacitor bank is also grounded. From the copper input, a well-insulated busbar leads to the central electrode. This is a cylinder of iron, aluminum or copper, 5–6 mm in diameter, which is tightly surrounded by a quartz glass tube. It rises above the water surface by 2–3 mm, the electrode itself is lowered down by 3–4 mm. A cylindrical hole is formed into which a drop of water can be dropped. The end of the copper wire from the negative pole of the capacitor bank must be secured to a long hard rubber handle.

If you quickly touch the copper input with this spark gap, a plasma jet will fly out from the central electrode with a pop, from which a spherical plasmoid will separate and float in the air. Its color will be different: a bright whitish plasmoid will fall from the iron electrode, green from the copper electrode, and white with a reddish tint from the aluminum electrode: such plasmoids are seen by pilots when lightning strikes the plane.

To get real ball lightning, you need to insert a cylinder of porous carbon into a quartz tube. Such coals are used in arc spectral analysis. Porous carbon can be impregnated with various solutions and suspensions. If you apply a water extract from the soil to the electrode, with organic matter, particles of coal and clay, then when discharged, classic “orange” colored ball lightning will fly out of the electrode. True, she will live no longer than a second, but this is enough to examine her in all details and admire her.

Obtaining real ball lightning is not difficult. You need linear lightning striking some kind of lightning rod, and damp air. Drawing by the author

In order to study the properties of ball lightning, we had to make thousands of them. First of all, electrical measurements have shown that ball lightning is, indeed, an autonomous formation: the current in the discharge circuit disappears after a tenth of a second, then the lightning moves freely and glows due to the accumulated energy. At the same time, by the way, it is not hotter than a cucumber in the garden. This paradox is associated with the special state of ions in the ball lightning core. Each ion generated during the discharge is immediately hydrated - in humid air it is tightly surrounded by water molecules. Opposite ions are attracted to each other, but water molecules prevent them from getting closer. A special state of matter arises—hydrated clusters. Computer modeling has shown that in hydrated plasma the rate of ion recombination slows down sharply. If in “dry” plasma it occurs in a billionth of a second, then for ions conserved in a cluster, recombination is delayed for tens and hundreds of seconds. During this time the lightning will glow.

In the ball lightning core, hydrated clusters with a large dipole moment form chain and fractal structures. A cloud of warm, humid air can accumulate enormous energy, up to a kilojoule per liter, if it receives it during discharge in the form of separated ions of different signs.

Thus, the mystery of ball lightning can be considered solved. But just recently it took its place among the mysteries of nature discussed on television and in the press, somewhere next to UFOs, the Tunguska meteorite and the Bermuda Triangle. And this is not surprising. The myth of ball lightning has fed more than one generation of journalists and scientists. In pursuit of sensation, colorful details were introduced into reports of ball lightning. The farmer's simple story: “There was a strong clap of thunder. A ball of fire, the size of a fist, ran down the drainpipe and dived into a barrel of water. The water gurgled. I walked over and stuck my hand in the water. The water seems to have become warmer...”, after four consecutive reprints in newspapers, turned into a scientific work on calculating the energy reserve in a volume the size of a fist, capable of evaporating a volume of water the size of a barrel.

According to the testimony of witness Sokolov, the cause of death of the Russian academician Georg Wilhelm Richmann (1711–1753) was ball, not linear, lightning. Richmann's setup for measuring atmospheric electricity consisted of a lightning rod connected by a wire to an ungrounded electrometer. Rice. M.V. Lomonosov The famous ball lightning hunter Igor Pavlovich Stakhanov (1928–1987) had to develop a special technique for interviewing eyewitnesses in order to separate reality from speculation and fiction. After critical processing of eyewitness accounts, Stakhanov - like James Dale Barry ten years before him - came to the conclusion that in most cases ball lightning is a luminous spheroid, 12-25 cm in diameter, freely floating in the air and existing 1–2 seconds. Less commonly, ball lightning has the shape of a torus or crown. It is usually painted in different shades of yellow-red, there are also gray-blue and lilac tones and, sometimes, greenish - from an admixture of copper.

Most lightning has a visible luminous core and a surrounding shell. Sometimes the core rotates around a horizontal axis. In rare cases, sparkles can be seen inside the zipper, like on a New Year's ball. It never chars paper or fabric and does not produce the feeling of a heated body. Usually it disappears without a trace, although sometimes it explodes with a sharp bang, like a balloon containing hydrogen or methane.

In the rarest cases, ball lightning can last ten seconds. The chemist Mikhail Dmitriev was lucky enough to observe remarkable lightning in 1867 on the river. Onege. The air that day was clean, well washed by rain. After a strong linear discharge with a thunderclap, ball lightning appeared above a long (130 m) raft of wet logs that formed a conducting plane. Ball lightning, with a gray-blue core and a bluish shell, slowly moved over the raft, gradually rising, came ashore and, after random movements among the trees, disappeared. It lasted for more than thirty seconds. Dmitriev managed to take air samples near the lightning. The analysis showed that the samples contained elevated levels of ozone and nitrogen oxides, as happens after a thunderstorm.

Ball lightning is far from the only natural phenomenon associated with atmospheric electricity. In addition to them, there are linear lightning, current jets, beaded lightning, blue jets and sprites, various forms of sitting discharges and St. Elmo's fire. Linear lightning is a formidable natural phenomenon - it is a powerful high-voltage breakdown of the humid atmosphere. Most often, a linear discharge occurs above the ground in the cloud layer.

Current jets, a rarer phenomenon, are the flow of electric charge through a channel left by linear lightning or a high-energy cosmic particle. Current jets are being intensively studied. They can be obtained artificially by launching a rocket with a wire tail into a thundercloud. An electric charge flows down the wire - a luminous trace with a round luminous head appears.

Under certain conditions, the head of the jet, enriched with electrons, can separate and exist for some time in the form of an autonomous luminous formation.

The current stream always moves along the line of least electrical resistance. It most often enters the house through a chimney, electrical wiring, telephone or television cable. It can fly into a window, flowing around the glass, and sometimes makes a hole in it.

In strong winds, when the air is electrified by friction, current jets appear in clear weather. Then the electric charge flows off invisibly, and only in the narrowness of the channel does a bluish glow appear.

In the mountains, in the pure rarefied air, current streams and the fires of St. Elmo appear more often than on the plain. Climbers often suffer from electric currents. Without going into details, they call them “ball lightning”.

A lightning discharge caused by firing a rocket with a copper wire tail into a thundercloud. Photo: Florida Lightning Research Group

The negative charge that comes to the surface of the earth during a linear lightning discharge spreads along a narrow electrically conductive channel. If this channel comes to the surface again, then a plasma jet can escape from it, from which ball lightning will separate and float. Rare eyewitnesses have seen the birth of ball lightning. All the more significant is the incident that occurred on one geodetic tower with a simple lightning rod made of an iron cable. It was carelessly buried at the base, its end sticking out of the puddle. When lightning struck the lightning rod, a dazzling jet burst out from the end of the cable, from which a luminous lump separated and floated in the air.

One of the most amazing and inexplicable properties of ball lightning is its ability to remove gold wedding rings from hands without causing burns. A gold or copper wire ring hung in the path of ball lightning loses part of its mass, which can be determined by weighing. Apparently, this phenomenon is associated with accelerated recombination of ions on the metal surface, which is accompanied by its sputtering.

Our ball lightning workshop was visited by hundreds of people who wanted to see a rare phenomenon: academicians, scientists, specialists in the field of atmospheric electricity, journalists, television people, and those simply interested in ball lightning.

Eyewitnesses of the natural phenomenon were especially grateful - the demonstration of ball lightning evoked in them memories of a previous meeting with them. New details were revealed. It turned out that there are many more observers of short-lived ball lightning than those surveyed by Stakhanov - many simply do not attach importance to their encounter with this fleeting phenomenon.

For some viewers, the flash of the plasma jet caused a persistent afterimage on the retina. It exists for ten seconds and moves in space when you turn your head. How can one not recall the theory that long-lived ball lightning is not a physical, but a physiological phenomenon.

Of course, this theory is not correct: ball lightning can certainly live for more than ten seconds. This is by no means a lump of plasma, as some believe. This complex physicochemical formation is a cloud of lukewarm, humid air with an abundant population of hydrated dissimilar ions bound into clusters that form a certain structure surrounded by a negatively charged shell. The physics of ball lightning is the physics of enormous currents at relatively low voltage.

It will take years to study such a complex state of matter in detail. The process can be accelerated if a decent premium is set for the method of sustainable production of long-lived ball lightning. We need international competitions to obtain the longest-lived ball lightning. Perhaps this will not be so difficult: it is known that some lightning rods on high-rise buildings are readily visited by lightning throughout the year. It is enough to place a basin of dirty water in the path of the charge drain to get a testing ground for creating real natural ball lightning. https://www.vokrugsveta.ru/telegraph/theory/388/

How to tighten a zipper dog?

1. The carriage must be pressed directly onto the zipper
2. Connect the lock links well
3. Using pliers, pinch the carriage directly in the center
4. Check the movement of the slider. If it is difficult to move through, loosen it with a screwdriver

As you can see, you can repair locks at home. But remember, without experience, you can completely ruin the thing. It is better to conduct experiments on old things, so that if the attempt fails, you won’t be sorry to part with them.

Types and designations of dogs

There are the following types of dogs, which also bear the name sliders:

• semi-automatic;
• automatic;
• haberdashery

In the first case, the zipper pawl has a built-in mechanism that prevents the fastener from coming apart. In the second case, when fastening clothes, you need to fix the slider stopper - if you lift the tongue, the fastener will immediately come apart. The haberdashery puller does not have fastening parts, so it is used only in zippers sewn into bags.

Dogs are classified according to their size and shape. They can be identified by the digital symbols applied to the back surface of the sliders:

• 3, 4, 5, 6, 7, 9, 10 – for oval-shaped sliders used for twisted zippers;
• 3, 5, 8, 10 – for triangular sliders with metal fasteners;
• 3, 5, 7, 8, 10 – for pawls with a reverse surface in the shape of a trefoil or an oval, used on tractor zippers.

In addition to numbers, Latin letters are written on the back surface of the sliders:

1. “A” indicates one-piece snake.
2. “B” indicates a split zipper with 1 lock.
3. “C” is applied to the slider of the detachable zipper with 2 locks.
4. “D” means that the zipper with 2 connectors and the same number of locks opens completely.
5. “H” is written if there are no connectors on the one-piece zipper and there are 2 locks.
6. “X” indicates a molded snake without connectors and with 2 locks.
7. “L” means that the tape does not open and has 1 lock.

How to consolidate the result?

After the dog sits still and the snake is opened a short distance from the end, you need to prevent a similar nuisance in the future. To prevent the same thing from happening next time, take care to securely fix the slider .
To do this, install metal stops that will prevent it from flying off the clasp. If there are none, then just take a needle and thread and create a semblance of them with a few stitches at the end of the zipper. There are times when the dog flies out of place because the edge of the zipper sewn into the fabric of the bag has come loose. After the slider returns, you need to sew up the problem area . And be sure to monitor the integrity of the cloves. Any problem is easier to prevent, and this one too. Also inspect the fixation of the edge of the clasp to the fabric of the bag. Detecting shortcomings in a timely manner will help you avoid getting into an awkward situation in the future.

Why push-up bras have been removed from billboards

Consequences of piercing

Do I need to vaporize the zipper?

In order to carry out this procedure, it is not at all necessary to remove the snake from the bag. The methods proposed below will allow you to put the slider in place without such tedious work as steaming and then sewing in the zipper. Not every woman will be able to cope with these operations on her own, because you need to work very precisely, without basting or adjusting.

To “return” the dog, we leave the zipper in place . You may have to slightly prop it up or trim it during the process.

Device, types and markings

Zippers come with one-way and two-way fasteners. Detachable zippers are used on warm, sportswear, as well as on jumpers and sweatshirts. They are usually of high quality. There are locks:

• tractor for down jackets and down jackets;
• spiral for thinner and more delicate fabrics, as well as for bags and wallets;
• metal for denim, shoes.

Locks have teeth of various sizes. On outerwear and products made from coarse materials, the zippers are usually larger; in delicate fabrics, zippers with small teeth are sewn.

The runners are also varied. There are the following types:

• automatic, when the dog locks the teeth in any position;
• a semi-automatic machine requires the installation of a stopper so that the lock locks and cannot be unfastened;
• The haberdashery runner cannot be fixed in a certain position.

The latter is installed on the locks of bags and wallets, semi-automatic devices are more commonly seen on shoes, and machine guns are more commonly seen on jackets and down jackets.

What is required for replacement?

First you need to prepare working tools and materials:

• a new lock with suitable parameters;
• a needle and thread, in some cases a sewing machine;
• screwdriver;
• pliers and pliers;
• stationery scissors or blade;
• glue “Moment”.

After determining the cause of the snake failure, you can begin to replace the slider. Every housewife should know how to dress a dog depending on the type of clothing being changed.

Dependence of the process on the type of lightning

Different types of snakes are sewn into bags:

• tractor;
• spiral;
• metal.

They are all one-piece, which means that there is only one slider.
For each type of zipper, a special type of pawl and stopper is produced. The most common snakes are tractor ones. Working with them, putting the slider in place, is simple: they easily connect the teeth and close the clasp, and are also quite plastic and pliable. It’s quite good to eliminate similar problems with spiral zippers. They are also based on soft plastic. But it’s not always possible to help metal snakes: if you need to close it, you won’t be able to connect the teeth together. This is exactly what the dog is designed for. Therefore, the most correct way out in this situation would be to completely replace the fastener.

How to put a runner on pants, a bag and shoes

One-piece metal or spiral locks are installed on shoes. They last a long time, but the pawl can fly off or break off if moved suddenly. If the latter happens, then remove the remains of the slider, remove the limiter and install a new slider, and return the limiter back.

The same technology can be used when changing the sliders on trousers and bags.

How to change the lock on a boot, watch the video.

High-quality locks usually last a long time. Most often you have to change the dog if it falls off or stops fixing the teeth. Do not rush to throw away the item if this happens, but fix it yourself. To replace the slider on your lock, use the tips above.

How to dress, put the dog on the zipper on the boots?

It is problematic to perform such a manipulation without experience, but using a narrow tool it is possible.

Pre-lubricate the lock: with a drop of vegetable oil, a piece of hard soap or a candle stub. This will soften the motion of the carriage.

1 option

1. We pull up the zipper from the bottom
2. Pull the edges of the tape out
3. Cut the fabric after the last teeth
4. Carefully expand the slider and remove
5. We install a new dog, having first unclenched it
6. Secure with pliers
7. Sew up the cut with tape
8. We insert the zipper into place, fix it with an even seam

Option 2

1. We rip the tape from above or remove the limiters with a screwdriver
2. We carry out manipulations similar to the first option

Option 3

1. We unclench the slider, without undoing anything, anywhere in the lock
2. Filming
3. We put a new one, we clamp it

How to insert a slider - step by step

If the pawl accidentally comes off the clasp when fastening the bag, but the zipper is closed, then proceed as follows:

1. inspect the place where the lock came off: most likely, the edge of the snake has come off a little and the end of the zipper is not fixed with fabric;
2. carefully insert the slider onto the edge of the clasp and pull the teeth into the lock;
3. if it works, separate the ends of the zipper, moving them to the sides;
4. if you can’t insert the teeth, then pry one of them with a needle and pull it up, then do the same on the other side with the other tooth. Continue to move the pawl down slowly;
5. if this does not work, then lightly support the edge of the fabric near the zipper and put on the pawl. You may have to trim both edges.

Important! Pulling the pawl down the fastener is not always convenient. Use a safety pin that can be inserted into the lock and the work will go faster.

If the slider has been removed from the open zipper, then it must first be connected . This is done with calm movements from side to side. The connection of the teeth must be carried out without gaps, otherwise the whole work will have to be redone. After completing the connection, take the pawl and put it on the clasp. Proceed according to the steps above.

Important! In this way, you can restore the integrity of the spiral or tractor zipper. The metal snake cannot be connected by hand, so the fastener will need to be replaced.

Sometimes the slider comes out of the fastener not at the end, but in the middle when the tooth comes out. In this case, putting the lock in place can only be done temporarily; in the very near future, the clasp will need to be completely replaced .

If for some reason it was not possible to put the dog in place or you simply don’t want to do it yourself, professionals at any bag or shoe repair shop will easily carry out this procedure for you in a matter of minutes.

Causes of lock malfunction

The most common lock problems are:

1. At some point he stopped moving normally, jumping out from the other side of the tape.
2. If the zipper catch breaks, it gets stuck or slides off the teeth.
3. The dog stopped being fixed when fastening, moving out of the fastener.

In some cases, if it breaks, only the slider needs to be replaced. If the fastener has torn or damaged teeth, it will need to be replaced.