Normal temperature water: tap water, purified water, mineral water and filtered water.

Summary:

1. all have white patterns of different sizes.

2. When water is solidified, the direction of expansion is random, so the shapes of patterns are almost all different.

Boiled water: tap water, pure water, mineral water and filtered water.

Summary:

1. all have patterns, and the volume is relatively reduced.

2. Boiling can reduce the white pattern, but it can't be completely removed.

How to get transparent ice cubes?

The method is as follows:

1. Use an open heat preservation container, or wrap an ordinary container with heat preservation material (foam paper or towel), open the lid, pour in cold boiled water and freeze.

2. Take out the ice cubes, the upper layer is transparent ice cubes, and bubbles gather at the bottom; Cut off the bubble or crack part and simply modify it to get transparent ice.

Principle description:

Before freezing: liquid water molecules, chaotic state.

After freezing: solid water molecules, six-membered ring structure, highly ordered state.

Direct freezing: there are patterns of different sizes and shapes.

Boil for 5 minutes and then freeze: the volume of the pattern is relatively reduced, but it cannot be completely removed (Figure 2-5).

Summary: White patterns will appear when different kinds of water make ice with ice grids; However, when boiling water makes ice, the patterns are greatly reduced, but it is impossible to make fully transparent ice cubes. In the end, we finally made a completely transparent ice cube, and the method is at the end of the article.

Experimental principle:

How does water form ice?

Microscopically, the ice formation of water occurs through the reorganization of hydrogen bond network. When the temperature decreases, water molecules recombine in order through hydrogen bonds, forming a six-membered ring lattice structure (Figure 8). Each water molecule is fixed at a hexagonal joint, and like a thin wire fence, many hexagons are piled up to form solid ice cubes.

What is the pattern in the ice?

It is air that has not escaped. Gas has a certain solubility in water. When the temperature drops, water molecules try to find their specific position in the solid lattice. At this time, the dissolved gas and other substances in water become an obstacle and are discharged by the lattice structure being formed. Because the solidification of water in the refrigerator is from the outside to the inside, the gas can't escape smoothly, and is gradually rushed to the inside of the ice, forming tiny bubbles with the condensation of water.

Can these bubbles be eliminated?

It can be reduced, but it cannot be completely eliminated. Temperature will affect the solubility of gas in water. As the temperature rises, the solubility of gas decreases. Therefore, boiling water for a few minutes can remove the dissolved gas in the water. On the contrary, the lower the water temperature, the more gas dissolved in the water. After boiling water, a small amount of gas will still be dissolved in the freezing process, forming bubbles inside the ice cubes. Completely transparent ice cubes cannot be made by boiling water alone.

How to make transparent ice cubes?

Control the speed and direction of ice crystal growth. Use an open incubator, or wrap the ordinary container with heat insulation material (foam paper or towel); Pour it into the cold boiled water, and put it into the freezing area of the refrigerator (Figure 6).

At this time, the speed of water freezing slows down, the direction is from top to bottom, and bubbles gather at the bottom; After 24 hours, the ice cubes were taken out, and the ice cubes at the bottom were cut off and simply modified to obtain completely transparent ice cubes (Figure 7).

In addition, the ice made by the ice-making mechanism has high transparency, and its principle is that ice is formed layer by layer by spraying water, and the ice making is finished before the water in the middle is frozen. Therefore, most ice cubes have hollow structures.