Does snow let in sunlight? Why is snow white? Why do snow and ice melt from salt?
Irina Senotrusova
Research project "Why is snow white?"
Research on the topic: « Why is snow white?»
Introduction
Winter came. It became cold outside. White the whole earth, all the trees were covered with a fluffy blanket. are falling white snowflakes, lie on the ground, on the roofs of houses, on trees, on people. Snowflakes look like white stars. They silently fall to the ground
I love looking at snowflakes. They're very beautiful. Like lace, everyone is different. Sometimes they stick together and fall to the ground in large flakes. Sometimes the cold wind breaks white stars, turning them into fine snow dust, and then it is very difficult to see them.
One morning I woke up and looked out the window. I saw that everything around: earth, trees, roofs of houses, became white. It fell out snow. I got lost in thought: "BUT why is snow white?» And I decided investigate this issue.
This problem allowed us to formulate the topic research: « Why is snow white?»
Target: studying and conducting experiments to answer a question « Why is snow white?»
Tasks:
1. Study the literature that talks about snow study the information provided on the Internet
2. Prove experimentally « Why is snow white?»
3. Summarize the knowledge gained by presenting it at the competition
Methods research:
1. Studying the literature on the topic
2. Observation of the object research
3. Conducting experiments
4. Analysis of the results and conclusions on the conducted research
Hypothesis: Let's pretend that white color of snow associated with the reflection of light.
Conclusion: snow white because each snowflake reflects light in different directions. Scientific language - "light is scattered". From this snow white.
What snow?
What snow? This is a lot, a lot of beautiful snowflakes; they fall and fall from a height on the ground, on trees, on the roofs of houses - clean, fragile, sparkling.
Meaning of the word « snow» i found in "Modern Explanatory Dictionary". Snow- this is solid atmospheric precipitation, consisting of small ice crystals, falling out of clouds at temperatures below 0C. Snow formed when water vapor in the atmosphere freezes. At first, tiny crystals appear. Following the air currents, they move in all directions. Gradually crystals "stick" to each other until there are a hundred or more of them. When the size of the frozen ice floes is large enough, they begin to sink to the ground. These accumulations of ice floes are what we call snowflakes.
Where do snowflakes come from?
A snowflake is a frozen water crystal that has the shape of a six-ray polyhedron.
Water vapor rises high above the ground. It is very cold at the top, and ice crystals form from it. They are very small. It's not snowflakes yet. Falling down, the crystals rapidly increase. This is because there is a lot of water vapor in the air, which settles on their surface and freezes. So an ice-crystal becomes a beautiful, delicate snowflake.
There are so many snowflakes and they are all different - no one is the same.
The largest snowflake ever recorded was 12 cm in diameter. Typically, snowflakes are about 5 mm in diameter with a mass of 0.004 g.
The crystals that make up snowflakes have a certain shape. This is either a six-pointed star, or a thin plate that has the shape of a hexagon. The fact is that the main water crystal has the shape of a regular hexagon in the plane.
In 1885, American farmer Wilson Bentley took the first successful photograph of a snowflake under a microscope. He has been doing this for 46 years and has taken over 5,000 unique shots. Based on his work, it was proved that there are no two identical snowflakes.
Crystals of various shapes form at different temperatures.
The most beautiful snowflakes fall where the climate is harsher - for example, in the north.
For the formation of large flakes of snowflakes, complete calm is necessary, the longer the snowflakes travel, the more they collide and grapple with each other.
At low temperatures and strong winds, snowflakes collide in the air, crumble and fall to the ground in the form of debris - "diamond dust".
Why is snow white?
We're so used to color snow that we don't even think about why is snow white. It turns out that all the colors we perceive depend on the sun's rays. Black objects completely absorb sunlight, and therefore are perceived by us as black. And if the object completely reflects a ray of the sun, then the color will seem to us white.
Snow- this is frozen water, and as we know, ice is colorless. Why is snow white?? From the Internet and children's encyclopedia "Everything about everything" I learned that snowflakes are 95% air. Snowflake crystals are not smooth, but have edges. Reflection of light from the facets of these crystals makes snow white. The ice remains colorless, as it passes the entire sunbeam through itself. And each snowflake would pass all the light through itself and would also have no color. But snowflakes usually fall on top of each other in erratic motion. And already together they become opaque, and white. To figure it out why is snow white, why it reflects the rays of the sun, we need to look at the composition snow. Snow is formed from snowflakes, and snowflakes - from a huge number of crystals. These crystals are not smooth, but with edges. Therein lies the answer to our question, why is snow white. It is from the edges that sunlight is reflected. The water in the atmosphere is steam, it freezes and transparent crystals form. From the movement of air, the crystals move freely up and down. In this chaotic movement, the crystals are connected to each other. And when too many crystals gather together, then they begin to fall to the ground already in the form of snowflakes familiar to us. Turns out the color snow white, because the light of the sun, which it reflects, is white.
Interesting Facts:
№1 : Do you know that snow is not always white? In many regions of the world, people have seen it red, green, blue and even black! The reason for this variety of colors are tiny bacteria, fungi, and dust in the air that are absorbed by snowflakes as they fall to the earth's surface.
Conclusion:
1. Snow are solid atmospheric precipitation, consisting of small ice crystals.
2. Each snowflake is a collection of small pieces of ice.
3. Snow is formed from snowflakes, and snowflakes - from a huge number of crystals.
Experimental work
I put snow on red cardboard, compared it with white sheet of paper.
Conclusion: Snow white.
I took a transparent plastic bag. He cut it into small pieces. Each piece is "snowflake". I put all the pieces in a transparent glass. They positioned themselves differently.
Result: « snow» in a white glass.
He poured water into a glass and put it in the freezer. The water turned into clear ice. Mom broke the ice into small pieces. He became white.
Pieces of a plastic bag and pieces of ice are individually transparent. Light passes through them and is not reflected. When pieces of the package and pieces of ice lie chaotically (differently) they reflect light in different directions and we see them white.
MBOU secondary school No. 1, Sychevki, Smolensk region
Research project on the topic
"Why is snow white"
DESIGNER:
2nd grade student
Nikolaeva Violetta
Project Manager:
primary school teacher
Baikova Yana Viktorovna
2015/2016 academic year
The content of the work
Relevance……………………………………………………3
Introduction……………………………………………………...4
Main part
Theoretical part……………………………………………….4
Practical part……………………………………………..6
Conclusion…………………………………………………...7
Sources of information……………………………………..8
Relevance
White snow fluffy
Spinning in the air
And the earth is quiet
Falling, laying down.
And in the morning with snow
The field is white
Like a veil
All dressed him up.
One cold winter Sunday morning, I woke up to the fact that there was a lot of light in the room. I looked out the window and saw thatall around
: earth, trees, roofs of houses,road, parked cars.. –all
became white. It was the first snow.And from him wasso much light
that seemed to be standing aroundtransparent ringing silence
. He was white, fluffy and clean.
I thought: “Why is the snow white?”
Introduction
Objective of the project:
study and conduct experiments to answer the question
"Why is snow white?"
Project objectives:
1. Study literature, information on the Internet that talks about snow.
2. Prove experimentally "Why is snow white?"
Object of study: snow.
Hypothesis: suppose that the white color of the snow is due to the reflection of light.
Research methods: 1. The study of literature on the topic.
2. Observation of the object of study.
3. Conducting experiments.
4. Analysis of the results and conclusions on the study.
Main part
Theoretical part
Previously, it was believed thatSnow is frozen water droplets.
The mystery of the birth of snowflakes was solved quite recently. Snow will never be born from water droplets. Droplets of water can become hailstones, lumps of opaque ice that sometimes comes with rain in summer.
In fact, it is water vapor that rises high above the ground to where extreme cold reigns. There, immediately, tiny hexagonal ice-crystals are formed from water vapor, which grow all the time, develop and, finally, become an amazingly beautiful star-snowflake.Any snowflake has the shape of a six-pointed star, but it is impossible to find 2 completely identical snowflakes, since they are individual in shape.
So, I found out that a snowflake is water vapor that has turned into ice crystals.
What color is the ice? You will be right if you say there is none. It passes the entire sunbeam through itself and remains colorless.Each snowflake individually would also freely pass a ray of the sun through itself and would also be colorless, like ice. But the snowflakes slowly descend, gather into flakes and fall on each other in disorder.All together they become opaque, do not let the rays through themselves, but on the contrary, reflect them into the eyes. This is why snow looks white to us.
Regardless of the shape of the snowflakes, they are all white. And the snow is white-white, and if the sun shines, it becomes dazzling white. Why? A snowflake consists of ice and air crystals, the light falling on the rays of a snowflake is reflected from them, scattered and perceived by us as white. And when a sunbeam hits the crystals, it is reflected from it and blinds our eyes, and the snow seems to us blindingly white.
I decided to conduct experiments to prove that snow is really white.
Practical part
Experience number 1.
I 
took a transparent plastic bag. She cut it into small pieces. I imagined that each piece is a “snowflake”.
I put all the pieces in a transparent glass. They positioned themselves differently. Result: the so-called "snow" in the glass is white.
Experience number 2.
H 
I poured water into a glass and put it in the freezer. The water turned into clear ice.
M 
ama broke the ice into small pieces. He became white.
As a result of the experiments, I saw that the pieces of a plastic bag and pieces of ice are individually transparent. Light passes through them and is not reflected. When the pieces of the bag and ice lie chaotically, that is, in different ways, in disorder, they reflect light in different directions and appear white to us.
Conclusion
Now I can answer my own question with confidence -Snow is white because each snowflake reflects light in different directions. Scientific language - "light is scattered." From this, snow is perceived by us as white.
Sources of information
1.Children's encyclopedia. "I know the world." - M .: AST Publishing House LLC, 2001.-557 p.: V. A. Markin.2. Photos from the home archive taken during the experiments - 2014
Marina Shkerina
Research project "Why is snow white?"
The project was carried out jointly with the child.
Introduction
Winter came. It became cold outside. The whole earth, all the trees were covered with a white fluffy blanket. White snowflakes fall, fall on the ground, on the roofs of houses, on trees, on people. Snowflakes look like white stars. They fall silently to the ground.
I love looking at snowflakes. They're very beautiful. Like lace, everyone is different. Sometimes they stick together and fall to the ground in large flakes. Sometimes a cold wind breaks white stars, turning them into fine snow dust, and then it is very difficult to see them.
One morning I woke up and looked out the window. I saw that everything around: the ground, the trees, the roofs of the houses, became white. It was the first snow. I thought: “Why is the snow white?” And I decided to investigate this problem.
This problem allowed us to formulate the research topic: “Why is snow white?”
Having decided on the topic, she set herself the goal: to study and conduct experiments to answer the question “Why is snow white?”
To achieve this goal, you need to solve the following tasks:
1. Study literature that talks about snow.
2. Prove experimentally "Why is snow white?"
3. Summarize the knowledge gained.
Object of study: snow.
Subject of study: snow composition
Hypothesis: suppose that the white color of the snow is due to the reflection of light.
Research methods:
1. Studying the literature on the topic
2. Observation of the object of study
3. Conducting experiments
4. Analysis of the results and conclusions on the study
Chapter I. Theoretical substantiation of experimental work.
1.1 What is snow?
What is snow? This is a lot, a lot of beautiful snowflakes; they fall and fall from a height on the ground, on trees, on the roofs of houses - clean, fragile, sparkling. And then it fell - this amazing snow. He lay down with “magnificent carpets”, covered the ground with a white veil. The fallen snow filled up all the pits, ditches, leveled the hillocks - completely transformed the plain. The forest has changed even more. The snow scattered in white tufts over the branches of the trees, covered the leaves and branches that had fallen to the ground with a white blanket, and lay down in tall snowdrifts in the bushes. To an attentive eye, he revealed many secrets of forest life - everything that happened was imprinted on the snow cover, left traces in the snow.
I found the meaning of the word "snow" in the Modern Explanatory Dictionary. Snow is solid atmospheric precipitation, consisting of small ice crystals, falling from clouds at temperatures below 0C. Snow is formed when water vapor in the atmosphere freezes. At first, tiny crystals appear. Following the air currents, they move in all directions. Gradually, the crystals “stick” to each other until there are a hundred or more of them. When the size of the frozen ice floes is large enough, they begin to sink to the ground. These accumulations of ice floes are what we call snowflakes.
1.2 Where do snowflakes come from?
A snowflake is a frozen water crystal that has the shape of a six-ray polyhedron.
Water vapor rises high above the ground. It is very cold at the top, and ice crystals form from it. They are very small. It's not snowflakes yet. Falling down, the crystals rapidly increase. This is because there is a lot of water vapor in the air, which settles on their surface and freezes. So an ice-crystal becomes a beautiful, delicate snowflake.
There are so many snowflakes and they are all different - no one is the same.
The largest snowflake ever recorded was 12 cm in diameter. Typically, snowflakes are about 5 mm in diameter with a mass of 0.004 g.
The crystals that make up snowflakes have a certain shape. This is either a six-pointed star, or a thin plate that has the shape of a hexagon. The fact is that the main water crystal has the shape of a regular hexagon in the plane.
In 1885, American farmer Wilson Bentley took the first successful photograph of a snowflake under a microscope. He has been doing this for 46 years and has taken over 5,000 unique shots. Based on his work, it was proved that there are no two identical snowflakes.
Crystals of various shapes form at different temperatures.
The most beautiful snowflakes fall where the climate is harsher - for example, in the north.
Depending on the weather conditions, “own” snow falls in different places.
For the formation of large flakes of snowflakes, complete calm is necessary, the longer the snowflakes travel, the more they collide and grapple with each other.
At low temperatures and strong winds, snowflakes collide in the air, crumble and fall to the ground in the form of debris - “diamond dust”.
1.3 Classification of snowflakes.
Prisms- there are both 6-coal plates and thin columns with a 6-coal section. Prisms are tiny and almost invisible to the naked eye. The edges of the prism are very often decorated with various complex patterns.
Needles- thin and long snow crystals, they form at a temperature of about -5 degrees.
When viewed, they look like small light hairs.
Dendrites- or tree-like, have pronounced branching thin rays. More often these are large crystals, they can be seen with the naked eye. The maximum size of a dendrite can reach 30 cm in diameter.
12-ray snowflakes- sometimes columns with tips are formed with the rotation of the plates relative to each other by 30 degrees. When rays grow from each plate, a crystal with 12 rays is obtained.
hollow posts- inside columns with a hexagonal section, it happens that cavities are formed. Interestingly, the shape of the cavities is symmetrical with respect to the center of the crystal. High magnification is needed to see half of the small snowflakes.
fern-like dendrites- this type is one of the largest. The branches of stellate dendrites grow thin and very frequent, as a result, the snowflake begins to look like a fern.
Irregular crystals- snow crystals are often small, asymmetrical and fused with each other. To get beautiful symmetrical crystals, you need to have a good combination of many weather conditions.
triangular crystals- such snowflakes are formed at a temperature of about -2 degrees. In fact, these are hexagonal prisms, some of the sides of which are much shorter than others. But on the faces of such rays can grow.
bullet sockets- sometimes during the formation of crystals they can coalesce and increase in random directions. Such formations are easily broken into separate crystals, similar to bullets. Hence the unusual name.
1.4 Why is snow white?
When a Russian person is asked to imagine winter, the first thing he sees in his imagination is snow, a snow-white cover that has enveloped everything around. We are so used to the color of snow that we don’t even think about why snow is white. It turns out that all the colors we perceive depend on the sun's rays. Black objects completely absorb sunlight, and therefore are perceived by us as black. And if the object completely reflects a ray of the sun, then the color will appear white to us.
Snow is frozen water, but as we know, ice is colorless. Why is snow white? From the Internet and the children's encyclopedia "Everything about Everything" I learned that snowflakes are 95% air. Snowflake crystals are not smooth, but have edges. The reflection of light from the facets of these crystals makes the snow white. The ice remains colorless, as it passes the entire sunbeam through itself. And each snowflake would pass all the light through itself and would also have no color. But snowflakes usually fall on top of each other in erratic motion. And already together they become opaque, but white. To understand why snow is white, why it reflects the rays of the sun, we need to look at the composition of snow. Snow is formed from snowflakes, and snowflakes are formed from a huge number of crystals. These crystals are not smooth, but with edges. This is the answer to our question why snow is white. It is from the edges that sunlight is reflected. The water in the atmosphere is steam, it freezes and transparent crystals form. From the movement of air, the crystals move freely up and down. In this chaotic movement, the crystals are connected to each other. And when, finally, too many crystals gather together, then they begin to fall to the ground already in the form of snowflakes familiar to us. It turns out that the color of snow is white, because the light of the sun that it reflects is also white. Think if a ray of the sun turned green or yellow, then the color of the snow would be the same. Surely, many have noticed that during sunrise or sunset, it seems to us that the rays of the sun become pinkish, and the snow at this moment seems pink to us.
Interesting Facts:
#1: Did you know snow isn't always white? In many regions of the world, people have seen it red, green, blue and even black! The reason for this variety of colors are tiny bacteria, fungi, and dust in the air that are absorbed by snowflakes as they fall to the earth's surface.
Conclusion on Chapter I
1. I learned that snow is solid atmospheric precipitation, consisting of small ice crystals.
2. Each snowflake is a collection of small pieces of ice.
3. Snow is formed from snowflakes, and snowflakes are formed from a huge number of crystals.
Chapter II. Organization of experimental work
on the problem "Why is snow white?"
From my observations, studying the literature, I learned that any snowflake has the shape of a six-pointed star. Regardless of the shape of the snowflakes, they are all white. And the snow is white-white, and if the sun shines, it becomes dazzling white. Why? A snowflake consists of ice and air crystals, the light falling on the rays of a snowflake is reflected from them, scattered and perceived by us as white. And when a sunbeam hits the crystals, it reflects from it and blinds our eyes.
I decided to conduct experiments to prove that snow is really white.
2.1 Conducting experiments to answer the question "Why is snow white?"
How I did my experiments
Experience #1
I put the snow on red cardboard, compared it to a white sheet of paper. Conclusion: Snow is white.
Experience #2
I took a transparent plastic bag. She cut it into small pieces. Each piece is a "snowflake". I put all the pieces in a transparent glass. They positioned themselves differently.
Result: "snow" in a white glass.
Experience #3
She poured water into a glass and put it in the freezer. The water turned into clear ice. Mom broke the ice into small pieces. He became white.
Conclusion
Pieces of a plastic bag and pieces of ice are individually transparent. Light passes through them and is not reflected. When the pieces of the package and lie randomly (in different ways, they reflect light in different directions.
Conclusion
Snow is white because each snowflake reflects light in different directions. Scientific language - "light is scattered." This makes the snow white.
When thinking about winter, a snow-white cover always appears in the imagination, enveloping everything around, and rarely does anyone think about why it is white.
Droplets of water in the atmosphere, at sub-zero temperatures, freeze and turn into ice, falling to the ground in the form of snow. Ice is water in a solid state, it is transparent in itself. Then why is snow white?
Snowflakes also have no color, but if you look at them through a magnifying glass, you can see that they look like crystals, resembling a regular hexagon with edges in their shape. During a snowfall, it is the edges of the snowflakes that reflect the light rays that give the snow its usual white color.
On the ground, snow cover is a cluster of snowflakes located very tightly to each other in a chaotic manner. Together they reflect light with greater force, so even at night, when the surface is not illuminated by the sun, we see snow as white. The source of light rays at night are the moon, stars, lanterns.
However, the reason for the "whiteness" of the snow cover lies not only in the ability of the faces of ice crystals to reflect the light falling on them, but also in the purity of their surface. The bottom line is that no snowflake can be perfectly transparent. In the atmosphere, water droplets mix with various particles (dust, industrial emissions and other pollutants) that are able to absorb unreflected light rays.
Why does snow glitter?
In this case, the well-known law applies: the angle of incidence is equal to the angle of reflection. Billions of microcrystals, having the shape of a regular hexagon, absorb the sun's rays, refract them, and then reflect in different directions and at different angles, like "sunbeams". Therefore, we see how snowflakes sparkle and shimmer in the sun.
Why do snowflakes crunch and creak underfoot?
Walking through the snow, you can often hear a crunch or creak under your feet. Such a sound is obtained because the crystals of snowflakes rub against each other under mechanical pressure and break. However, this phenomenon can not always be observed, but only at a certain air temperature.
The fact is that snow creaks only at temperatures from 2 to 20 degrees below zero, and in different temperature intervals, creaking and crunching are accompanied by a special sound. This is explained by the fact that in severe frost, the crystals of snowflakes become denser and stronger, and at temperatures of 0 ° C and above, the snow cover loses its strength and begins to melt.
In fact, even the break of one small snowflake is accompanied by sound. But this sound is so weak that the human hearing organs simply do not perceive it. While trillions of snowflakes are breaking, the sound becomes much stronger and a person can clearly hear the characteristic crackling of snow.
When examining a single snowflake closely, you can see that it is transparent. But snow, which consists of thousands and thousands of transparent snowflakes, is white. How does it work?
This is because light has different wavelengths. Each wavelength has its own color. The distribution of colors by wavelength can be seen in the picture below.
Some materials can absorb waves of a certain wave, while others reflect them. That is why objects have different colors. For example, some materials reflect short wavelengths of blue, but longer wavelengths are absorbed, so we see a blue object. Other materials are red because they only reflect the wavelength characteristic of red. A material that reflects all waves incident on it will appear white, while a material that absorbs all waves will appear black.
Snow, as you know, is frozen water. If you look at water, you can see that it is transparent, which means that light waves pass through it. Therefore, it is not surprising that the snowflake is also transparent. If you pass a beam of light through one snowflake, it will not be reflected, but, having passed through the smallest ice crystals, it will be refracted at an angle. No wonder they say: “no two snowflakes are the same”, because they all have a diverse and unique shape. When a beam hits another snowflake, it will again be refracted at some angle, then another and another and so on until it hits our retina, and our brain interprets the information received as white.
Freshly fallen snow that does not contain impurities refracts light waves until they are reflected back, which is why it appears completely white. But sometimes even on pure snow you can notice some bluish tint. In this case, everything depends on the density of the fallen snow (if we exclude the presence of impurities). If it is sufficiently loose, then long light waves penetrate it a little deeper, while short, predominantly blue, remain on the surface. We just observe them.
Illustration: depositphotos.com
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