Interesting facts about autumn in nature. Interesting facts about autumn
EDUCATIONAL EVENT
“Solving a design problem” for students in grades 3-4
Stage 1. Conversation.
Dear guys, you are offered a project task-game
“In spring, snow in the city always melts faster than outside the city. Sasha offered his explanation for this and said that to check he would need a sheet of black paper, a lamp and a thermometer. What assumption did Sasha make and what item required for testing did he forget to name?”
By doing it you will be able to show a lot of what you learned at school. The peculiarity of this task is that it involves a group of students of different ages or different classes. We hope that each of you will find your place in the game and be able to benefit your group. But in order for everything to work out, in the process of solving this problem you will have to agree on what part of the overall problem each of you will solve, come to each other’s aid, show the ability to prove your point of view and treat the opinions of your comrades with understanding.
The design task is carried out in two stages. At the first stage, you will prepare to solve problems, and in the second, you will go to a scientific laboratory, conduct a series of experiments and make a report on how the experiment went and what its results were. .
While conducting research, you will need to complete a number of tasks. You can move from table to table, and perhaps you will perform some tasks at the same time, distributing them among you. It may be more convenient for you to work on the content of the assignments not in the sequence in which they are given. The main thing is to try to complete the work in the allotted time (80 minutes). There will be a break between stages.
We wish you to show your best human qualities, as well as knowledge and skills.
There are two photographs on the board: 1 - a road in a field at the edge of the forest and 2 - a road in a city among houses.
Look at these pictures the guys took. Where do the events take place? If you were an artist, what paints would you need most? Why?
You are now sitting at tables and there are white and black mugs taped to each seat. These are teams of 6 people. Divide into teams by color and come up with a name for your teams.
TASK No. 1
Here is a map of the Solntsevo Park area. One group will go in the direction indicated on the route sheet and you must plot this route on the map. And the second one plots its route in the direction indicated on the second route sheet. The first and second groups must come to their experimental site and conduct research there that will help solve our problem.
ROUTE LIST – 1
Exit the school building (marked with an asterisk on the map), turn northeast and walk 350 m, then turn southeast and walk another 350 meters. Next you turn east and walk 250 meters to the bend, turn northwest and walk 100 meters. In front of you is your experimental site.
ROUTE LIST -2
Exit the school building, turn southwest and walk 400 meters. Then turn west and walk another 100 meters. Approach the edge of the forest near the pond and in front of you is your experimental site.
TIPS FROM AN EXPERIENCED TRAVELER
The main requirement for the route is its safety. When planning a transition, you should avoid obstacles, since it is when overcoming them that danger awaits travelers, in addition, overcoming obstacles requires more time than going around them along a longer path. When planning a route, you should carefully study the map of the area, as well as descriptions made by those who have already visited these places. Pay attention to the surroundings, vegetation, roads, population. Follow traffic rules.
Stage 2. Equipment for the experiment.
On this table there are objects that you can take for the experiment.
Equipment: sheets of black and white paper, table lamp, thermometer, stopwatch, 3-minute hourglass
What items did you choose and what will they be needed for?
1 pair – keeps time,
2nd pair - records the results,
3 pair – determines the temperature.
Determine the name of the professions that do this work. (on the board: weather forecasters, accountants, time manager)
Conduct an experiment to answer the problem.
Enter the data from your experiments on the observation sheet.
observation sheet
Study No.
t° C
at first
Time (minutes)
t° C
at the end
Average temperature (for the purity of the study)
Stage 4. Presentation of the work of groups 1 and 2.
RESULT: Drawing up a conclusion-answer to the problem based on the observations of four groups.
When the first snow falls on the ground, and airy fluffs cover everything around with a soft snow-white carpet, it seems as if there is nothing weightless than a tiny and small snowflake: it weighs about a milligram and rarely reaches three.
It’s amazing how, in a matter of hours, snow-white precipitation manages to cover vast expanses of land with a thick fluffy blanket, which turns out to be so heavy that it directly affects the speed of rotation of our planet. For example, snow in the summer, in August, covers only 8.7% of the entire surface of the Earth, while its weight is 7.4 billion tons, and by the end of winter, before the beginning of spring, its mass doubles.
Snow is a type of precipitation that consists of small ice crystals that fall onto the surface of our planet from nimbostratus clouds in the winter, creating a snow cover that constantly or with minor interruptions covers the earth's surface until the arrival of spring.
In the region where snow has fallen, sub-zero temperatures are established, keeping precipitation in crystalline form.
When temperatures rise above zero, the snow melts, and if this process occurs at the beginning of spring, this symbolizes the end of the cold period. Ice crystals do not fall out everywhere: people living in countries located in equatorial latitudes (Africa, Australia, South America, Southeast Asia, New Zealand and some countries of Central Asia) are unfamiliar with snow.
Snowflakes fly to the ground from nimbostratus clouds after water droplets adhere to condensation grains, tiny dust particles, located in the clouds. If the temperature in the upper atmosphere is from -10°C to -15°C, the precipitation will be of a mixed type, consisting of drops and ice crystals (in this case, it will be sleet or rain), and if below -15° C – will consist only of ice crystals.
When the formed crystals begin to move up and down the cloud, they gradually increase due to the droplets sticking to them (they partially melt and crystallize again). As a result, the ice floes acquire six-pointed plates or stars, the rays of which are either at an angle of 60 or 120 degrees. After this, new crystals begin to stick to the tops of the rays, to which drops also freeze, as a result of which snowflakes take on a wide variety of shapes.
The crystals are usually white, which they acquire due to the air trapped inside them: after snow has fallen, the sun's rays, bouncing off the air and the boundary surfaces of the snowflake, scatter and give it a snow-white appearance. It is worth noting that any snowflake is 95% air, and therefore is characterized by low density and slow falling speed (about 0.9 km/h).
The following types of ice precipitation exist:
- Crystals - their diameter is several millimeters, they are mainly hexagonal in shape;
- Snowflakes - each contains about a hundred crystals fastened together, which in case of wet precipitation can reach large sizes (up to 10 cm in diameter);
- Frost – extremely cold and small droplets (such as fog);
- Hail - this snow usually falls in the summer in the form of large, hard pieces of ice and is formed when large drops stick to the crystal.
Types of snow cover
After snow falls for the first time, climate winter comes (a period when temperatures are below zero degrees Celsius for five days). If the temperature in the lower layers of the atmosphere, while the snowflakes are falling down, turns out to be very low and a strong wind blows, the crystals will begin to collide with each other, break, crumble and fall to the ground in the form of debris.
But if ice crystals begin to fly to the ground at above-zero temperatures, wet snow will fall. It is worth noting that if rain and snow fall from a cloud at subzero temperatures, the precipitation will freeze to the road and form ice.
The snow on the ground is constantly changing. How exactly the snow cover will look depends largely on winds (they make it uneven), rains (they compact it), thaws, seas (in the east of Russia there is much more ice precipitation than in western Europe: due to the influence of the Atlantic Ocean, precipitation here it falls as rain).
There are the following main types of snow cover:
- Fluffy snow - after snow has fallen, it remains an untouched fluffy cover for some time. This snow in winter is notable for the fact that it is a soft cushion, and therefore a fall usually occurs without injury: the loose snow softens the blows. It is very difficult to move along it, it may well hide stones, ice, tree branches underneath, and due to the fact that it is impossible to accurately determine the depth of the snow cover, you can suddenly find yourself knee-deep in a snowdrift and even get stuck.
- Hard - the more people trample the snow cover, the harder it becomes. If it is not rolled out, then moving around is much easier.
- Crust is a crust of hard ice that covers fluffy snow. It is formed by the sun and the wind: the snow melts first under the sun's rays, after which the cold air freezes it again. The crust can be soft, medium and hard: the soft crust will fall through, you can walk on the hard crust, and if it turns out to be medium, the pedestrian will either slide or fall through. In the mountains, weak adhesion between crust and snow can cause an avalanche.
- Ice is frozen wet snow that has melted several times and frozen again. This type of snow cover is the most unpleasant because it is very hard, smooth, slippery, and a fall can have serious consequences that can lead to injury or even death. You need to move along it very carefully and, if possible, avoid it.
- Wet snow - after air temperatures rise above zero, ice crystals begin to melt and, filling with water, turn into sleet. As a result, snowflakes begin to stick together and form lumps of ice. Walking on it is quite dangerous: you can get your feet wet, which can lead to a wide variety of diseases, and if you slip, you can end up in cold water and get wet.
Time of snowfall
Since our planet's climate has been changing so much lately, given the unpredictability of the weather, it is quite difficult to predict when the first snow will fall. For example, in Yakutia, Chukotka, and the Krasnoyarsk Territory, the first snow can be seen already in early October, and snow melts in some areas only in June.
But in Oymyakon (located south of the Arctic Circle) it is impossible to determine when the first snow will appear. Despite the fact that permanent snow cover here usually appears at the end of September, it can also be seen in August (snow melt in this region occurs in the spring, at the end of May).
As for Europe, the first snow here occurs already at the end of October or at the beginning of November (the very first snow was recorded in the seventies in Moscow: it fell on September 25). It falls mainly at night, when the air temperature drops and gives snowflakes the opportunity to reach the ground.
The first snow does not last long: during the day, when temperatures rise significantly, and disappears within a few hours. But after a permanent winter cover is established, the snow remains for a long time, until spring: the snow finally melts in March or even April.
As for the southern hemisphere, the northernmost points where snow has ever fallen are Buenos Aires in South America, the Cape of Good Hope in Africa, and Sydney in Australia. True, it melts quickly and falls infrequently: for example, in July 2007, snow fell in Buenos Aires for the first time in eighty years (the reason is cold air from the Arctic). According to meteorologists, they witnessed a rare event; this type of precipitation can only be observed here once every hundred years.
Melting
Snow usually melts in the spring when temperature changes occur: snow melts at temperatures above zero degrees Celsius. There are often situations when it melts at sub-zero temperatures (under the influence of sunlight: ice crystals evaporate, bypassing the liquid stage) .
If the snow is dirty, it melts faster (which is why it disappears much faster in the city than in the forest): the sun's rays heat the dirt, causing the snow to melt.
Salt also often helps the snow cover disappear; it does not melt the ice flakes, but destroys the crystals, which first cool and then return to ambient temperature in the form of salt water, creating the impression that the snowflakes have melted.
When the snow melts in the spring, the density of the snow cover changes very quickly. At first it is 0.35 g/m3, then 0.45 g/cm3, and at the very end it reaches its critical density of 0.6 g/cm3. T Snow melting ends when wet snow reaches a density of 0.99 g/m3 and turns into water. After this, the long-awaited spring comes.