Materials: square colored paper, pencil, scissors, glue.

1. Square origami is folded diagonally to form a triangle, and then the triangle is folded along the center line to form a smaller triangle.

2. Draw three lines on the isosceles triangle from the open side and divide the triangle into four parts.

3. Use scissors to cut along the pencil mark, being careful not to cut it, and then expand it to get the picture below.

4. Glue the two corners in the middle together.

5. Glue the second layer together in the direction opposite to step 3.

6. The method of the third layer and the fourth layer is the same, and the bonding direction is opposite to that of the previous step each time. The final product, as shown in the figure, is a piece of snowflake.

7. According to the above steps, make six snowflakes, and then stick the six snowflakes together with glue, and the three-dimensional snowflake is ready.

Causes and process of snowflake formation

First, the formation reason:

Snowflakes grow from small ice crystals, and most ice molecules are hexagonal, so most snowflakes are hexagonal, and the shape of each snowflake is not exactly the same. The diversity of snowflake shapes is closely related to the water vapor conditions when it is formed.

Hexagonal flake ice crystals have different saturated vapor pressures because of the different bending degrees of their surfaces, edges and corners, of which the saturated vapor pressure on the edges is the largest, followed by the edges and the plane is the smallest.

Second, the formation process:

As the ice crystals grow, the water vapor near the ice crystals will be consumed. Therefore, the closer to the ice crystal, the thinner the water vapor and the lower the supersaturation. Close to the surface of the ice crystal, because the excess water vapor has condensed on the ice crystal and just reached saturation. Water vapor molecules first meet the corners and protrusions of ice crystals, where they condense and make ice crystals grow.

Therefore, the corners and protruding parts of ice crystals will grow rapidly first and gradually branch. Later, for the same reason, new branchlets will grow in every branch and corner. At the same time, in the depression between each corner and fork. The air is no longer saturated. Sometimes, there is even a sublimation process here, which allows water vapor to be transported to other places.