Children are able to puzzle parents and other adults with questions: “Why is the sky above us blue?”, “Why does the sun shine?”, “Why does the river flow?” ... In winter, a favorite children's question is: “Why is snow white, crunches and creaks underfoot?” " And it’s worthwhile to deal with this interest right away, because the current winter is not the last, and if you hush up the question now, then it will be in front of parents only in a year.
Snow color
Why snow crunches underfoot, we will figure it out a bit later, first we will determine the first part of the question. Children who are ripe for him already know that snow is frozen water, that is, ice. The ice is transparent, respectively - colorless, so why is snow white?
If you catch a snowflake and look closely at it, it is easy to make sure that it is also mostly transparent. It acquires color only when its edges reflect light - all the same, sunny or artificial. And if snowflakes were neatly stacked in a pile, they would seem transparent, except that the edges would be painted - in the color of the sky or the nearest advertising billboard. However, snow falls randomly, faces are exposed to the sun at different angles, reflect and refract it, again chaotically. As a result, the eyes perceive the freshly fallen snowdrift as perfectly white (of course, if there are no clouds in the sky).
When the snow crunches
Now it remains to find out why the snow creaks underfoot. Remembering that snowflakes are ice, the answer to this question is not too difficult. The ice crystals that they are are quite fragile, albeit hard. With pressure on them (for example, under the mass of a person walking in the snow), the snowflakes are destroyed, emitting a faint crunch. It is accompanied by the same almost (but only almost!) Soundless creak from the friction of tiny ice floes one against the other. If only one snowflake broke, the human ear would not be able to hear such a quiet sound. However, their tens of thousands, and even millions - and the crunch with a creak become audible. In addition, between the individual snowflakes in the snowdrift from the frost, very thin bond-bridges appear, invisible to the eye, but adding their own touch to the noise.
When the snow does not creak
The offspring are not always satisfied with the answer: either they consider it abstruse, or it does not coincide with their vision of the world. However, more often the following questions arise, logically arising from your explanations: “And then why does the snow crunch under your feet in cold weather, and when it’s not very cold - no?” First of all, because snowflakes become more flexible, elastic and do not break right away during insignificant cold weather - many have time to melt under pressure. Friction between the individual crystals is also absent - it is “lubricated” with water, which does not have time to freeze. And the bridge-layers are also not formed, so there is nothing to burst. Accordingly, the question: “Why is snow crunches underfoot” will not arise for a child walking nearby. True, only until the next cold snap!
However, parents who have explained why the snow is crunching under their feet and who have relieved the sweat from their forehead, should not relax. Very soon their child will please them with the following question - and who knows how successfully it will turn out to answer it.