For experiments with soap bubbles in the cold you need to prepare diluted in snow water shampoo or soap, to which is added a small amount of pure glycerine, and a plastic tube from a ballpoint pen. Bubbles easier to blow in a closed cold room, because on the street almost always winds. Large bubbles are easily blown using a plastic funnel for pouring liquids.
Bubble during slow cooling freezes at about -7°C. the Coefficient of surface tension of soap solution slightly increases upon cooling to 0°C, and upon further cooling below 0°C decreases and becomes zero at the moment of freezing. Spherical film will not shrink, despite the fact that the air inside the bubble is compressed. Theoretically, the diameter of the bubble should decrease during cooling to 0°C, but on such a small value that practically this change is hard to define.
The film is not fragile, which would seem to be a thin crust of ice. If given the opportunity soap zakristallizuetsya bladder to fall on the floor, he will not break, will not turn ringing in fragments, like a glass ball, which decorate the Christmas tree. It will be dents, separate fragments will twist in the tube. The film is not fragile, she discovers plasticity. The plasticity of the film turns out to be a consequence of its small thickness.
Offer you four entertaining experience with soap bubbles. The first three experience should be carried out at a temperature of -15...-25°C, and the last one at -3...-7°C.
Carry a jar of soapy water on the bitter cold and blow air bubble. Immediately at different points on the surface appear small crystals, which have been growing rapidly and finally merge. Once the bladder is completely frozen, in its upper part, near the end of the tube, there is formed a dent.
The air in the bubble and the bubble shell be more chilled at the bottom, because the top of the bubble is less chilled tube. Crystallization is distributed from the bottom up. Less chilled and thinner (due to Oceania solution) the upper part of the shell of the bubble under the action of atmospheric pressure sags. The stronger cools the air inside the bubble, the greater the dent.
Lower end of the tube in a soap solution, and then remove. On the lower end of the tube will remain the column of solution height of about 4 mm, Attach the end of the tube to the surface of the palm. The column is greatly reduced. Now wydobyte bubble until rainbow coloring. The bubble happened with very thin walls. This bubble behaves in the cold kind: as soon as it freezes, so immediately bursts. So get frozen bubble with very thin walls never fails.
The thickness of the bladder wall can be considered equal to the thickness of a monomolecular layer. Crystallization begins at certain points the film surface. Water molecules at these points should be close to each other and arranged in a certain order. Restructuring in the arrangement of the water molecules and the relatively thick films do not break the bonds between molecules of water and soap, the finest of film collapse.
In two jars pour evenly soap solution. In one, add a few drops of pure glycerin. Now from these solutions one by one flush two approximately equal to the bubble and put them on the glass plate. Freezing bladder with glycerin flows a little differently than bubble out of solution shampoo: delayed start, and the freezing is slower. Note: frozen bubble out of solution shampoo is stored in the cold longer than frozen bubble with glycerol.
Wall frozen bubble out of solution shampoo - monolithic crystalline structure. Intermolecular connections anywhere exactly the same and durable, while in the frozen bubble from the same solution with glycerin strong links between water molecules is weakened. In addition, these ties are broken by the thermal motion of molecules of glycerol, so the lattice quickly sublimates, and then quickly collapses.
Weak cold blow air bubble. Wait until it ruptures. Repeat the experiment in order to ensure that bubbles do not freeze, regardless of their withstood the cold. Now prepare a snowflake. Flush the bladder and then reset it on top of the snowflake. It will immediately fall down to the bottom of the bubble. On the spot where stood the snowflake that starts the crystallization of the film. Finally, the whole bubble will freeze. If you put the bubble on the snow - he is also after a while it will freeze.
Bubbles on low frost cooled slowly and supercooled. Snowflake is the center of crystallization. Snow occurs the same phenomenon.