Objective of the project:
- find out what affects the change in leaf color
Project objectives: What should I do:
- study specialized literature,
- find out what changes happen to a tree during the year,
- justify that all these changes occur under the influence of nature,
- conduct an experiment to determine the presence of chlorophyll in leaves,
- conduct a survey among classmates and make a qualitative analysis of the results.
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Research project
“Why do the leaves change color?”
Demyanenko Sofia Denisovna,
Student 3 "B" class,
MBOU "Secondary School No. 31 with UIP HEP"
Supervisor:
Yurkina Svetlana Vladimirovna,
Teacher primary classes
MBOU "Secondary School No. 31 with UIP HEP"
Nizhnevartovsk, 2017
Introduction. | ||
Main part | ||
2.1. | Theoretical part | |
2.2. | Practical part | |
Conclusion. | ||
Information source |
- Introduction.
The world of vegetation that surrounds us is very beautiful and diverse. Around, especially in summer, people are surrounded green color- an abundance of fresh grass, beautiful lush trees and bushes. Many people know that vegetation provides us with oxygen, but why the leaves are green may not be known to everyone.
Autumn owes its charm to balanced natural processes. Not a single leaf falls from a tree just like that. This is a single endless cycle in which each element obeys the laws of Nature. Trees are diverse, and therefore the substances contained in their leaves are different. Depending on the presence of certain substances, the leaves turn different colors in the fall.
The flora is diverse and beautiful. When we think or talk about nature, an abundance of lush green grass and oxygen-rich trees covered with green foliage immediately come to mind. And why Are the leaves green? The theme of my project is motivated by the desire to explain the miraculous transformations in nature.
My hypothesis:
- If you observe nature, you can find out the pattern of changes in leaf color.
Theoretical significance work is
- that in it I try to understand why leaves change color.
Practical significance work is
- that the information collected will be used in lessons the world
Description of positive changesthat will occur as a result of the project upon its completion and in the long term:
- Inform the guys
Object of study:
- tree leaves
Subject of study:
- change in leaf color.
Methods, which were used in the study:
- survey,
- observation,
- qualitative and quantitative analysis of results.
Objective of the project:
- find out what affects the change in leaf color
Project objectives: What should I do:
- study specialized literature,
- find out what changes happen to a tree during the year,
- justify that all these changes occur under the influence of nature,
- conduct an experiment to determine the presence of chlorophyll in leaves,
- conduct a survey among classmates and make a qualitative analysis of the results.
Research methodology:
- Searching for information on the Internet;
- Carrying out practical research(questionnaire, survey, dialogue, experiments).
- Conducting an experiment to determine the presence of chlorophyll in leaves.
2. Main part.
2.1. Theoretical part.
WITH howl bright appearance living vegetation is acquired in the spring and retained throughout the summer. Knowledge from biology helps to find out why plant leaves are green.
What does the leaf consist of?Leaves, along with the root and stem, are the main vegetative organs plants. However, leaves differ from all other organs in their particularly complex structure. Botanists distinguish between the external (shape, color) and internal (tissue) structure of a plant leaf. I would like to note that the process of photosynthesis, which is so necessary for all living beings, including humans, directly depends on the structure of the leaf. Any damage to the leaf structure will prevent photosynthesis from occurring.
External structure of a plant leaf.All plants are different, so their leaves also have different shapes. In almost all plants, the leaf consists of a petiole and a leaf blade. The latter performs all the main functions of the sheet, as it consists of all the main components. The petiole is a strongly narrowed part of the leaf, with the help of which it is attached to the stem. Due to the fact that the petiole has fairly good elasticity, the leaf blade is able to withstand heavy loads, for example, the impact of raindrops. Some plants have special stipules near the petiole that protect young leaves. Each leaf is positioned on the stem in such a way as to avoid eclipsing each other. This is a kind of adaptation of the plant for survival.
Internal structure of a plant leaf.The inside of the leaf blade is covered with transparent skin, the so-called epidermis of the plant. This skin consists of a complete layer of living cells intertwined with each other. Main function such a system is protective. Further, columnar tissue is distinguished in the leaf structure of the plant. This tissue is cylindrical in shape and takes part in photosynthesis. Since columnar tissue is necessary for photosynthesis, it is located on the upper side of the leaf. Also in the leaf there is a spongy tissue of a round shape, which also serves for the process of photosynthesis, and also participates in gas exchange and in the evaporation of water from the leaf. The majority of the leaf structure is occupied by conductive tissue. It consists of specific veins that are divided into bast and wood. These veins carry sugar (glucose formed during photosynthesis) from the leaves to all other organs of the plant. That is, they perform the transport function of glucose throughout the plant. The veins contain fibers. These are thick-walled cells that protect the leaf veins from damage. In internal structure The leaf of a plant cannot fail to mention chloroplasts. Green plastids, with the help of which organic substances are formed in young foliage, are the main component of any plant.
I have learned that In autumn, the leaves on the trees change their usual green color and fall. We say: nature is dying. Scientifically speaking, this process is driven by chlorophyll, a substance found in tree leaves. The thing is that the color of the leaf depends on the content of this very substance in it. It turns the foliage green. With the onset of cold weather, the production of chlorophyll stops and its decomposition begins. At this moment, other pigments begin to appear that were always present in the foliage, but were drowned out by chlorophyll.
A plant cell consists of chloroplasts (if you look at a plant leaf under a microscope, you will immediately see them), and chloroplasts, in turn, contain chlorophylls - green pigments. They participate in the most important process of photosynthesis, which ensures the respiration, growth and nutrition of the plant (if you have forgotten the phenomenon of photosynthesis, you can read about it in the article What is photosynthesis). When a ray of sunlight hits a leaf, chlorophyll reflects the color green and absorbs the rest of the colors in the solar spectrum. It is worth noting that the color on the sheet may be different saturation. Bright colors indicate a large accumulation of chlorophyll, dull colors indicate insignificant ones. There are also other pigments in the leaf. With the coming of autumn sunlight becomes less and less, so chlorophyll, so to speak, loses its former strength, and the leaf changes color, since other pigments prevail in it. That's why we can admire the pleasant green in spring and summer, and in autumn, watch the sharp change in shades to bright yellow and hot red.
2.2. Case study
I asked my classmates a few questions about my research topic to find out what they thought: “why do leaves change color?”
- Who paints the leaves green?
- Why are they green in the summer?
- Why do they change color in autumn?
- Why are conifers green all year round?
- Why are they only green in the summer and different colors in the fall?
Conclusion: The survey showed that many do not know the reason for the change in leaf color. Most students believe that the culprit for leaf color is the change of seasons or the tree itself. Several guys (4 people) thought in in the right direction- their change of leaf color is influenced by the sun.
Experience: Evidence of the presence of chlorophyll pigment in the leaf.
In order to make sure for myself that there is chlorophyll in the leaves, I conducted an experiment with my biology teacher Olga Romanovna. Olga Romanovna made a thin cut on the sheet. I placed the cut between the pieces of glass. And through a microscope I saw chloroplasts, which contain chlorophyll.
- Conclusion.
Working on the project gave me the opportunity to read interesting material about nature, I acquired new knowledge - I learned
- what is chlorophyll and why is it needed,
- What the color of the leaves depends on the pigments it contains;
- that in spring all leaves are equally colored due to the presence of the pigment chlorophyll, which absorbs all colors except green;
- that after the destruction of chlorophyll the leaves change color and in the leaves coniferous trees chlorophyll is not destroyed, so they always remain green.
Conclusion: Trees are diverse, and therefore the substances contained in their leaves are different. Depending on the presence of certain substances, the leaves turn different colors in the fall.
- Informational
MBOU Tyomkinskaya Municipal Secondary comprehensive school
Municipal municipality "Tyomkinsky district" of the Smolensk region
Research project
Secrets of the autumn leaf
2nd grade students completed:
Tyapkina Christina,
Shulepova Irina.
Head: Nikitina Lyubov Ivanovna,
primary school teacher
With. Tyomkino
1. Introduction. 3
2. Main part. We reveal the secrets of the autumn leaf. 4
Chapter 1. Our observations.
Chapter 2. The first secret. Why do leaves change color?
Chapter 3. The second secret. How does leaf fall occur?
Chapter 4. The third secret. Why do trees shed leaves?
3. Conclusion. 9
4. List of used literature. 10
5. Applications:
No. 1. Drawings and photographs.
No. 2. Herbarium.
No. 3. Crafts made from dried leaves.
Introduction
Autumn is a wonderful time of year. The change in leaf color is one of the first signs of autumn. Lots of bright colors in the autumn forest! Birches and maples turn yellow, patterned rowan leaves become crimson-red, and aspen leaves turn orange and crimson. At this time of year it’s good to wander through the autumn park, breathe fresh air, observe nature, collect bouquets from fallen leaves, admiring the yellow, crimson, purple colors.
During the excursion, we collected foliage for crafts, and we became interested in why the leaves changed color in the fall and why even in the summer they could not be picked strong wind, and in the fall they come off on their own? What happened? What secrets does the autumn leaf hide?
The purpose of our research: to find out why autumn changes occur in the life of trees.
Study the reasons for changes in leaf color in autumn;
Find out how leaf fall occurs;
Study the causes of leaf fall;
Conduct observations of autumn phenomena in the life of trees;
Learn and check folk signs associated with leaf fall.
To find answers to the questions posed, we looked for information in scientific books, encyclopedias and reference books on this topic, accessed Internet resources, and made observations.
2. Main part. We reveal the secrets of the autumn leaf.
Chapter 1. Our observations.
We watched the leaves change in the fall.
In September, yellow leaves appeared on some trees, but the connection with the branches was still strong. Before anyone else, the leaves on the birch and linden trees began to turn yellow. The birches began to turn yellow from below.
In October, almost all the leaves changed from green to yellow, brown, red and leaf fall began. The leaves of alder and lilac did not change color. In rainy weather the leaves seemed paler, in sunny weather they seemed somewhat brighter. Unfortunately, we were not able to observe how a decrease in temperature affects the brightness of the color of autumn foliage, since there were no frosts during leaf fall.
The leaf fall passed quite quickly. The leaves fell off the maple trees in front of the school within a few days. By mid-October there were almost no leaves left on the trees.
In November, Almost all deciduous trees have lost their leaves.
We checked some folk signs associated with leaf fall. Two of them were confirmed.
1. If birch trees turn yellow from the top in autumn, next spring will be early, and if from below, then late.
Most of the birches that were observed began to turn yellow from below. Spring
came late. In March there were very coldy and unprecedented snowfalls, Spring came only in April.
2. The leaf fall has passed quickly - the cold will soon come and the winter will be harsh, and if the leaves remain green and stay on the trees for a long time - the winter will be short, with slight frosts . This sign was also confirmed: winter began at the right time, it was both frosty and snowy.
Chapter 2. The first secret. Why do leaves change color?
The forest is like a painted tower,
Lilac, gold, crimson,
A cheerful, motley wall
Standing above a bright clearing
I. Bunin “Falling Leaves”
After studying the literature, we learned why leaves change color in autumn. They are colored green by chlorophyll, which is constantly destroyed and restored again thanks to sunlight. In summer, the sun shines for a long time, the formation of chlorophyll does not lag behind its destruction. The leaf remains green all the time. Autumn is coming, the nights are lengthening. Plants receive less light. Chlorophyll is destroyed during the day, but does not have time to be restored. The green color in the leaf decreases, and yellow becomes more noticeable: the leaf turns yellow.
But in autumn the leaves become not only yellow, but also red, crimson, and purple. It depends on what coloring substance is in the withering leaf. (Appendices No. 1, 2)
The autumn forest is rich in its colors! The brightness of autumn leaves depends on what the weather is like. If autumn is long and rainy, the color of the foliage due to excess water and lack of light will be dull and inexpressive. If cold nights alternate with clear sunny days, then the colors will match the weather - rich, bright.
Alder and lilac leaves will fall green, regardless of the weather. In their leaves, in addition to chlorophyll, other coloring matter No.
Chapter 3. The second secret. How does leaf fall occur?
Leaf, leaf, leaf fall!
Who is to blame for this?
Maybe the wind is mischievous
Did you decide to play with the foliage?
S. Randa “Leaf, leaf fall”
Leaf fall is the biological process of plants shedding their leaves.
No one tells a tree when to shed its leaves. But now autumn is approaching - and the leaves on the trees change green. Nutrients begin to be drawn from the leaves into the trunk.
Changes also occur in the leaf petioles. The petiole consists of “bricks” (cells) and thin tubes (vessels), through which nutritious juices flow from the tree. Leaves need them for growth and development. In summer, the “bricks” are tightly connected to each other and just as firmly attach the leaf to the branch.
Try picking a green leaf, for example, from a birch tree. It is easier to tear it than to separate it without causing any damage.
And in the fall? The more the leaf turns yellow or red, the easier it breaks off. And there comes a moment when you just touch a leaf and it immediately falls from the branch.
In autumn, the connections between the bricks in the petiole are destroyed because the chlorophyll grains, which produced building material for the entire tree, have collapsed. A special cork layer is formed. It is like a partition between the petiole and the branch. The leaf is supported only by thin fibers. Even a slight breath of wind breaks these fibers. Leaves are falling.
Chapter 4. The third secret. Why do trees shed leaves?
Autumn is knocking on our window,
It's getting colder every day.
And the trees suddenly stripped,
Do you know that they don’t care about the cold?
They took off their hats and coats -
The leaves are on the ground.
Why are they on the branches?
Don't want to leave the leaves?
Although our deciduous trees They live for tens, often hundreds of years, their leaves “work”, just one season.
In a green leaf, the entire lower surface is covered with transparent skin and dotted with small holes - stomata. Under the influence of ambient temperature and air humidity, they either open or close. Like windows in houses. The water that the root absorbs rises up the trunk to the branches and leaves. When the stomata windows are open, moisture evaporates from the leaves, and new portions of water are drawn through the trunk into the crown.
The sun heats the leaf, and evaporation cools it. Trees need a lot of water. Over the summer, a large birch tree, for example, evaporates about 7 tons of water. In winter you won’t get as much moisture from the soil. Winter for trees is not only cold, but also, most importantly, dry time of the year. By losing leaves, trees protect themselves from “winter drought.” If the trees don’t have leaves, they don’t have such abundant evaporation of water.
In addition, trees need leaf fall medicinal purposes. The plant receives from the soil not clean water, and solutions of various salts. These salts, passing along with water through the entire plant, also enter the leaves. Some of them go to feed the plant, and the excess accumulates in the leaves. A large number of mineral salts disrupts the normal functioning of the leaves and becomes harmful to the plant.
The third reason for leaf fall: to protect thin, fragile tree branches from the weight of fallen snow. This is how leaf fall adapts trees to winter.
Leaves evaporate water
And in winter there is no water.
This means they won't have enough moisture.
And troubles cannot be avoided.
Blizzard on leaves in winter
There will be snow.
The tree will not withstand:
Maybe the snow will break it.
The leaves also accumulated
Salts are harmful during the summer.
The tree will shed its leaves,
And get rid of it.
That's why he comes
In the autumn forest or in the garden
Golden, rustling, quiet
LEAF FALL!
Conclusion.
Summing up the results of the research work, we can conclude that we have achieved our goal. We discovered the secrets of the autumn leaf: we learned that changes in the color of leaves occur due to a lack of sunlight, that in the fall leaves fall from trees so easily because the connection between the leaf and the tree branch is destroyed; that trees need leaf fall to survive dry and snowy winters and to get rid of unnecessary substances.
During the research, we collected and studied tree leaves, made a herbarium and compositions from this natural material, made sketches and photographs (Appendices). These materials can be used in lessons about the surrounding world, technology, and clubs. We learned to conduct observations, work with various sources of information, select the necessary material, and format our work.
We want to express our gratitude to our classmates who worked on the project with us and helped in the design of the work.
Bibliography
1. Graubin G.. Why do leaves fall in autumn? - Moscow, “Baby”, 1987, p. 24
2. Why and why. Encyclopedia for the curious. Ed. Pokidaeva T., Frolova T., - M.: Makhaon, 2007, p. 255
3. Pleshakov A. Atlas-determinant. From earth to sky - Moscow, “Enlightenment”, 2011, p. 222
4. Pleshakov A. The world around us. Textbook, 2nd grade - Moscow, “Enlightenment”, 2012, p. 144
4. Internet resources:
/2010/11/blog-post
/wiki/
Georgy Rudolfovich Graubin
Why is there leaf fall in autumn?
One spring I had to spend the night with a friend on the banks of the Siberian Onon River. We never managed to fall asleep: our teeth were chattering from the cold, although we covered ourselves with padded jackets and raincoats over our sleeping bags.
But imagine our surprise when in the morning we saw puddles that were not even covered with a thin crust of ice overnight! But in late autumn, when we went hunting, we slept in these same bags on nights when the puddles froze to the bottom, and the bank of a fast taiga river was frozen in strong ice!
It turns out that in the fall our body prepares for winter and is not afraid of the onset of cold weather. And in the spring, the hardening is lost - that’s why even a slight cold is so noticeable.
Not only humans, but all living things are slowly, gradually preparing to meet the cold weather. Bears and badgers, for example, store more fat for winter. Accumulate it the bats, mosquitoes. And in the body of ordinary black ants, tree beetles, caterpillars and other insects, a special frost-resistant substance appears in the fall.
Trees also have to withstand severe frosts. How do they deal with this? Trees cannot, like squirrels and partridges, huddle together for warmth; they cannot, like wood grouse, bury themselves in the snow to escape the frost. But they also prepare for winter in advance and in their own way.
WHY LEAVES TURN YELLOW
Autumn. Until the crackling winter frosts It’s still a long way off, but the trees are already beginning to gradually shed their leaves. Not immediately, not suddenly, they are freed from the leaves. Preparations are underway for leaf fall. Amazing transformations occur in the leaves.
First of all, the leaves begin to turn yellow. Although no one adds yellow dye to juices. Yellow dye is always in the leaves. Only in summer yellow unnoticed. It becomes clogged with a stronger one - green.
The green color of the leaves is given by a special substance - chlorophyll. Chlorophyll in a living leaf is constantly destroyed and re-formed. But this only happens in the light.
In summer the sun shines for a long time. Chlorophyll is destroyed and immediately restored, destroyed and restored again... The formation of chlorophyll does not lag behind its destruction. The leaf remains green all the time. Autumn is coming, the nights are lengthening. Plants receive less light. Chlorophyll is destroyed during the day, but does not have time to be restored. The green color in the foliage decreases, and yellow becomes noticeable: the leaf turns yellow.
But in autumn the leaves become not only yellow, but also red, crimson, and purple. It depends on what coloring substance is in the withering leaf.
The autumn forest is rich in its colors! The brightness of autumn leaves depends on what the weather is like.
If autumn is long and rainy, the color of the foliage due to excess water and lack of light will be dull and inexpressive. If cold nights alternate with clear sunny days, then the colors will be juicy and bright to match the weather.
But the leaves of alder and lilac will fall green, regardless of the weather. In their leaves, except for chlorophyll, there are no other coloring substances.
HOW LEAF FALL OCCURS
No one tells a tree when to shed its leaves. But now autumn is approaching - and the leaves on the trees change their green color. Already in August, the leaves of birch and linden begin to turn yellow, and in early September the golden plumage of Norway maple appears. In September, the foliage of the rowan trees turns red, at the end of the month they put on the yellow and bright red outfit of the aspen... Everything is like clockwork.
And indeed, trees, like all living things, have their own internal “clock”. This “living clock” is sensitive to the change of day and night.
The shorter autumn days seem to turn an invisible switch in the plant. Green color is replaced by yellow. Nutrients begin to be drawn from the leaves into the trunk.
Changes also occur in the leaf petioles. In summer, the leaf petioles are firmly attached to the branches.
Try to rip green leaf, for example, near a birch tree. It is easier to break it than to separate it from the branch without any damage.
And in the fall? The more the leaf turns yellow or red, the easier it breaks off. And there comes a moment when you just touch the leaf and it immediately falls from the branch along with the petiole. Just yesterday, even a strong wind could not tear off the leaves, but now they are falling off on their own.
What happened?
It turns out that in the fall, a so-called cork layer appeared at the base of the petiole, in the place where it is attached to the branch. He, like a partition, separated the petiole from the branch. Now only a few thin fibers connect the leaf petiole to the branch. Even a slight breath of wind breaks these fibers. Leaves are falling.
WHY DO TREES LOSE LEAVES
Although our deciduous trees live for tens, often hundreds of years, their leaves “work” for only one season. And during this time they still wear out quickly. After all, the “work” of leaves is very intense.
In a green leaf, the entire lower surface, covered with transparent skin, is dotted with small holes - stomata. Under the influence of ambient temperature and air humidity, they either open or close. Like windows in houses.
The water that the root absorbs from the soil rises up the trunk to the branches and leaves. When the stomata windows are open, moisture evaporates from the leaves, and new portions of water are drawn through the trunk into the crown.
The sun heats the leaves, and evaporation cools them and prevents them from overheating. Apply a leaf to your cheek - it cools.
A green leaf picked from a tree dries quickly. And on a tree, the leaves are juicy and fresh - the cells of a living leaf are always filled with water.
Trees need a lot of water. Over the summer, a large birch tree, for example, evaporates about 7 tons of water. In winter you won’t get as much moisture from the soil. Winter is not only a cold season for trees, but also, most importantly, a dry season. By losing leaves, trees protect themselves from “winter drought.” If the tree doesn’t have leaves, it doesn’t have such abundant evaporation of water.
In addition, trees also need leaf fall for medicinal purposes.
Along with water, the tree absorbs various mineral salts from the soil, but does not use them completely. Excess accumulates in the leaves, like ash in furnace fireboxes. If the leaves did not fall, the tree could poison itself.
Regional competition research work And creative projects
preschoolers and junior schoolchildren“I am a researcher!”
Municipal budgetary educational institution
“Secondary school “No. 18”
Engelssky municipal district
Saratov region
Individual project on the topic of:
"Why leaves
change color in the fall?
Vorfolomeeva Daria
1st grade student
project Manager
Eterevskaya Lyudmila
Vladimirovna
primary school teacher
MBOU "Secondary School No. 18" EMR
Saratov region
Saratov, 2015
Description of the project…………………………………………………………………………………. With. 3 - 5
Introduction……………………………………………………………………………… p. 3
Project stages and expected results…………………………………... p. 4 - 5
Stage 1: choice of research method, research progress……………… …… p. 4
Stage 2: study of literature on this topic, expected results...p. 4
Stage 3: generalization and systematization of information……………………………p. 4-5
Stage 4: product selection project activities…………………………… With. 5
Conclusions (importance of the project for use in practice)…………… … p. 5
Reflection on project activities…………………………………………….p. 5
Information and methodological support…………………………………… p. 6
Applications:………………………………………………………………………………………. With. 7 - 9
Why do leaves change color in autumn?
Project Description
Here is a maple leaf on a branch.
Now it's just like new!
All ruddy and golden.
Where are you going, leaf? Wait!
V.D. Berestov
Introduction
Autumn is a wonderful time of year. The change in leaf color is one of the first signs of autumn. Lots of bright colors in the autumn forest! Birches and maples turn yellow, patterned rowan leaves become crimson-red, and aspen leaves turn orange and crimson. At this time of year, my mother and I like to walk through an autumn park or forest, breathe fresh air, watch nature, collect bouquets from fallen leaves, admiring the yellow, crimson, purple colors.
One autumn, I was collecting beautiful leaves for technology lessons. Looking at them, I wondered: why did the leaves change color? Why did the color change from green to yellow and red? Why does a tree need leaves at all?
I suggested that the leaves change color due to lack of light or cold weather.
To answer these questions, I will conduct research.
Target: find scientific evidence reasons for changes in leaf color.
Tasks:
study specialized literature;
find out what significance a leaf plays for a tree;
study the reason for the change in leaf color;
answer the question: why some leaves turn red and others turn yellow;
development and design of an information booklet on the project topic
Project type:
by completeness: interdisciplinary
by number of participants: individual
Project stages and expected results
Stage 1 - organizational . The main method of this stage is observing changes in nature. Systematic observation of changes in the color of leaves on trees led to the conclusion that the color of leaves changes in different trees differently.
Observation results V Appendix 1.
I also used the method of surveying classmates. I found out - do they know why the leaves change color in the fall? The results are in Appendix 2.
Stage 2 – theoretical . The main method is studying literature and searching for information on the Internet.
Having studied the article in the encyclopedia for kids “Miracle is everywhere. The World of Animals and Plants” by T.D. Nuzhdina, and after reading the articles with my mother on the Internet, I realized:
what role does a leaf play in the life of a tree;
recognized the parts of the sheet;
discovered the reason for the change in leaf color in autumn;
found a lot of interesting additional information on this topic.
Stage 3 – practical. The main method is working with information.
Interest in this topic arose while walking around autumn forest. As a result of observations and studying literature, I learned new concepts and facts:
The leaves work all summer: they feed the tree, extract food from the air with the help of sunlight, and protect the branches and trunk from sunburn. The leaves that fell in the fall and remained lying under the trees will not be wasted. They will conserve moisture and protect the roots from frost. Then they will decay, fertilize the earth and feed the tree.
During the research I found Interesting Facts about changes in leaf color; picked up folk signs, proverbs, found the author's fairy tale about leaves, took photographs of autumn trees, made crafts from fallen leaves for technology lessons.
The information I received formed the basis for my speech, presentation, and information booklet for my classmates.
Stage 4 – final . The main method is to analyze the results of the work performed.
At the beginning of the project, I suggested that the leaves change color due to lack of light or cold weather. My assumptions were not confirmed.
I found out that in the fall, as the activity of the leaf fades, the formation of chlorophyll slows down and then completely stops; The destruction of chlorophyll under the influence of sunlight continues. As a result, the leaf loses its green color and yellow-red pigments appear.
I found scientific evidence of the reasons for the change in leaf color, that is, my goal was achieved.
conclusions
Working on this project gave me the opportunity to read interesting material about nature, I acquired new knowledge - I learned what chlorophyll is and what it is needed for, trained my powers of observation, learned to work independently, tried my hand at working on a computer and creative work with dry leaves. I applied the knowledge I gained in lessons about the surrounding world and technology. I spoke in front of my classmates and presented the results of my work.
Reflection
While working on the project, I learned to work with various sources information, evaluate the quality of my work, which I consider good, work in collaboration with my mother and teacher, and draw conclusions based on the data received. Also, working on the project helped develop my personal interest in studying nature and natural phenomena.
I think that I achieved my goal.
Information and methodological support:
T.D. Need E encyclopedia for kids “Miracle is everywhere. World of Animals and Plants", Yaroslavl Academy Holding 2003
Annex 1
Results of monitoring changes in foliage color
Appendix 2
Classmate survey results
Appendix 3
Fairy tale
Why do leaves change color in autumn?
Autumn has come. The leaves on the trees began to turn yellow and fall.
Once Marinka was sitting under an oak tree, looking at the yellowed leaves and thinking:
The leaves turn yellow from the cold. They tremble, cower, and the wind blows - and leaves fall from the branches and fly away. Only the oak tree still had leaves, but even on it there were fewer and fewer of them every day.
One day Marinka, a kind soul, could not stand it: she took glue and threads from home and ran to her beloved old oak tree. I started tying and gluing the last leaves to the branches so that the wind wouldn’t tear them off. Maybe the girl tied and glued 20 leaves, or maybe all 30. And she would have saved them, but her hands were completely frozen. Marinka sat down, put her hands to her mouth, breathing into her fists: first one, then the other. Then the wind flew in again - and suddenly it seemed to Marinka that the leaves above her head began to whisper and rustle. Then the oak seemed to stretch with a creak, yawned and said quietly:
What are you doing here, you idiot? Why are you disturbing me from sleeping?
“I didn’t want to wake you up,” Marinka was embarrassed. - I’ll paste the leaves for you, otherwise you’ll sleep through the last ones.
Eh, baby! I've finished my chores, it's time to rest. Look what acorns I grew, beautiful! Perhaps new oak trees will grow. But that’s later, and now the days are getting shorter, the light is getting less and less, which means it’s time for the trees to sleep. In the leaves, tiny green grains, living plants, disappeared and dissolved like sugar in water. There were no green seeds, and the leaves turned yellow.
But why yellow and not white or transparent? - Marinka was surprised.
Because besides green grains in the leaves there are also others - yellow ones. While the green seed grains were working in the leaves, no yellow ones were visible, but the green grains dissolved - and only yellow ones remained. The leaves have turned yellow. And then they dry up and fall off.
But how can this be? ! - the girl became worried. - What will you do without these little plants, without leaves? Who will feed you all winter?
“But I don’t want to eat or drink,” the oak tree whispered and yawned long. - It makes me sleepy. In winter, sleeping like this is a blessing. In winter, we trees do not grow or bloom. - Oak sighed and fell silent.
Hey! - Marinka quietly tapped on the wrinkled bark. -
I want to ask: maybe it would still be better if the leaves remained? Although they are dry and yellow, the tree is much more beautiful with them.
No, - the oak tree yawned. - We have no time for beauty in winter. We trees shed our own leaves. If you leave all the leaves, in winter such snowdrifts will grow on the branches that they will not be able to stand it and will break from the weight.
And I thought that the wind was tearing off the leaves.
“It’s possible without the wind,” the oak tree whispered. - We specially build up a thin partition between the petiole of the leaf and the branch, which does not allow juice or water to pass through. A septum grows and separates the leaf from the branch. As soon as the leaf has nothing to hold on to, it will break off and fly. The leaves will fall to the ground and the roots will be protected from the frost... Eh-he-he...
The girl wanted to ask the oak tree about the bark, about the buds, about the acorns, but then the wind blew again, and it seemed to her that the old tree was quietly snoring.
Morozova Victoria
Research activity “Why do the leaves turn yellow and fall off in autumn?”
Subject: « Why do leaves turn yellow and fall off in autumn??»
Relevance.
Plunging into everyday problems, adults stop paying attention to the world around them, while children are daily surprised by its seasonal changes.
Target research: To introduce children to the structure tree leaf and find out, why leaves the trees change color and fall.
Item research: Change tree leaves in the autumn season.
An object research: autumn leaves tree.
Hypothesis research: leaves trees will change their color and will fall in due time, because trees live their changing lives from season to season.
Target: Conduct an experiment with children that can confirm or refute our assumption. Is it possible to save leaves on the trees so that they do not change their color.
Tasks research:
1. Expand children’s knowledge about the life of trees in different time of the year.
2. Study the structure with children sheet, using a magnifying glass and microscope. Find out what is important leaves in the life of a tree.
2. Find out Why do the leaves change color and fall off in the fall?.
3. Conduct an experiment "Green leaves» .
4. Present the results research.
Methods research:
Experiment;
Observation;
The children of our group were conversations: about the life of trees at different times of the year, about the signs of the season « autumn» and etc.
A survey was conducted among parents on topic: « Why do some leaves on trees turn yellow?, others turn red, and others turn brown altogether.” The answer turned out to be quite simple. The fact is that in addition to chlorophyll leaves plants also contain other pigments, but due to the predominant green they are simply not visible. As the green chlorophyll recedes, other colors become visible.
Using a magnifying glass and a microscope, we studied the structure sheet. We first looked at the petiole - this is the part that connects leaf with branch, then the top surface sheet. We looked at the veins - thin tubes that run from the petiole throughout leaf. Top surface sheet absorbs sunlight and is therefore always darker than the bottom side sheet. edge the sheet is called"edge". Examined the edge sheet, the apex can be sharp or rounded.
Using a piece of white cloth, we conducted an experiment under name: « Why is the leaf green??» . Have taken leaf and placed it inside a piece of white cloth folded in half. Then a wooden cube was tapped firmly on the leaf through fabric. What did we discover during the experiment? Green spots appeared on the fabric. This is a green substance from leaf, is called chlorophyll, and it colors it green. When it comes autumn and it gets colder and there is less sunlight. This green substance gradually decreases until disappears completely. Then, the leaf turns yellow, brown or red.
Subsequently we made drawings leaves, which contain the required amount of chlorophyll, sketches of the structure sheet. This was a confirmation of one of the points of our experimental hypothesis.
By using table lamp, we conducted an experiment under name: "Green leaves» , which lasted several days. With its help, we observed the changes in color occurring leaves.
How did they change leaves:
yellow leaves get their color as a result "work" plant pigment xanthophyll;
Orange leaves put on their autumn attire when the carotene pigment becomes visible, which, by the way, is familiar to everyone from the bright orange color of carrots;
Reds leaves acquire this unexpected color thanks to anthocyanin pigments;
Brown leaves– this is no longer the coloring of pigments, but the coloring of cell walls sheet, it appears when other visible coloring pigments are absent.
Conclusion: Conducted by us study and the materials studied on the topic confirmed the theory of the irreversibility of time or "Law of nature". Since the conditions we created and the experience we carried out did not help preserve green leaves on tree branches.