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Мыльные пузыри и мороз






Для опытов с мыльными пузырями на морозе достаточно иметь разведенный в снеговой воде шампунь, мыло, фейри(наконец) и пластмассовую трубку от шариковой ручки или трубочки для питья. Большие пузыри легко выдуваются с помощью пластмассовой воронки для переливания жидкостей. Пузыри легче выдувать в закрытом холодном помещении, так как на улице обычно ветер.

К сведению. Пузырь при медленном охлаждении переохлаждается и замерзает примерно при –7°C.

Пленка оказывается не хрупкой, какой, казалось бы, должна быть тонкая корочка льда. Если дать возможность мыльному закристаллизовавшемуся пузырю упасть на пол, он не разобьется, не превратится в звенящие осколки, как стеклянный шарик, каким украшают елку. На нем появятся вмятины, а отдельные обломки закрутятся в трубочки.

Эксперимент. На слабом морозе при –3...–7°C выдуйте пузырь. Дождитесь, пока он лопнет. Повторите опыт с тем, чтобы убедиться, что пузыри не замерзают, сколько бы их ни выдерживали при таком морозе. Теперь приготовьте снежинку. Выдуйте пузырь и тут же сбросьте на него сверху снежинку. Она мгновенно соскользнет вниз на дно пузыря. На том месте, где остановилась снежинка, начнется кристаллизация пленки. Наконец, весь пузырь замерзнет. Если положить пузырь на снег – он также через некоторое время замерзнет.

Выдувайте мыльные пузыри на морозе и пишите у кого, что получится!

 

Superglue Replicas
This technique appeared recently in Popular Science magazine and was attributed to chemist Tryggvi Emilsson. The picture at right is from that article. The quality of the snowflake in the image is mediocre, but the replica looks pretty good. Here's how you do it: 1) Go outside with some glass microscope slides, cover slips, and superglue (not the gel kind; it should be thin and watery). Cover the slides and cover slips until they become as cold as the surrounding air. 2) Let snow crystals fall onto a cardboard collection board, and scan around with a magnifier to find an attractive specimen. Carefully pick the crystal up using a small artist's paintbrush and place it on one of the slides. 3) Place a drop of cold superglue on the crystal, and drop a cover slip on top. Be careful not to melt or otherwise damage the snow crystal in the process. 4) Leave the slide outside or in your freezer for a week or two until the glue hardens.  
Formvar Replicas
This preservation technique is described by Schaefer and Day [1]. It is similar to the superglue technique, but involves some different chemicals. Dissolve one gram of Formvar (polyvinyl acetal resin) in 100 milliliters of ethylene dichloride to make about a 1 percent solution of the plastic. According to Mason [3], best results are obtained when the Formvar solution is dehydrated by shaking it up with calcium chloride or phosphorus pentoxide to remove the dissolved water, which otherwise will come out when the solution is chilled and form spurious ice crystals. Also, it is particularly important to use a solution of the right strength. If it is too viscous, it will not fill small crevices on the crystals; if it is too thin, the solution will not form a thick enough layer. Good replicas of natural snow crystals may be obtained with a 1-3 percent solution. For crystals less than 0.1 mm in diameter, such as may be produced in laboratory experiments, a 0.1 percent solution can be used. Once you have the solution, use it much like the superglue described above.  
Acrylic Replicas
Another method uses clear acrylic spray paint, which is readily available in hardware stores. The spray is especially effective for replicating windowpane frost and similar ice structures. The (cold) spray must be applied lightly, since the solvent in the spray can dissolve the ice if too much liquid is present. The best procedure is to pre-coat the glass slide with the plastic film, place snow crystals on it, and then spray the surface again until the surface is moist. The image at right is from Walter Tape [4], and was obtained by spraying over a crystal that was placed on a glass slide.

 

Well APPARENTLY this is how to preserve a real snowflake...

Take one piece of glass (yes, I know, not exactly a child friendly activity, but they will hopefully appreciate the results!) - it was suggested you use a slide from a microscope, but I didn't exactly have one of those handy, so I took the glass out of a postcard sized picture frame!
Place the piece of glass in the freezer for at least 24 hours (making sure you tell everyone it's in there before they go in grabbing for the frozen peas!)
Place a tube of superglue in the freezer too (making sure the lid is securely fastened of course!)
When it snows, remove the items from the freezer, and attempt to catch a few snowflakes on the glass! ()
As soon as you have a few good snowflakes on the glass, place a blob of superglue over each one.
Place the glass back in the freezer asap, keeping it as level as possible so that the glue doesn't run.
Leave the glass in there for 4 weeks yes, 4 weeks!
Take glass out of freezer, and there you should have some beautiful little snowflakes preserved forever! If the glass was from a frame, place it back in the frame with black paper behind it! The patterns of the snowflakes are amazing, and the superglue kind of magnifies them!

(At some point remember to place the lid back on the superglue and remove it from the vicinity of small children! )

Well, of course, I had to have a go, only.... 1) when it snowed, I immediately went to get the glass from a picture frame without freezing it first, 2) left the glass on a wall outside to collect snowflakes on its own (well, it was too cold to be standing out there!) 3) went back out half an hour later only to find that I had a piece of wet glass on the wall!
Well, I should have known! But it was worth a try. Maybe if it's done properly it will work. It really did look good when they did it on the telly!
If anyone succeeds in this, please let me know!!
I now have a piece of glass and some superglue in the freezer on standby! It probably won't snow any more til next winter!

 






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