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Photosynthesis.

Plants: Natural Factories

Do you know why many businesses are now interested in plants and trees? Many industries talk about carbon credits (car-bon cred-its). This renewed interest in the plant world is because of photosynthesis (pho-to-syn-the-sis).

Plants have been called the "lungs of the Earth." This is because they carry out photosynthesis, the complex chemical process that produces oxygen for us and food for the plant. Because of photosynthesis, plants are the anchor of all food chains on Earth. Everything either eats plants or eats an animal that eats plants! As you read, you will discover why this natural plant process has been called the most important process on Earth.

Photo and Synthesis

In simple terms, photosynthesis is the way green plants use light to convert water and carbon dioxide (carbon dioxide) into the simple sugar, glucose (glu-cose). Oxygen (ox-y-gen) is given off during this process.

A careful look at the word photosynthesis helps you to understand the steps in this process. Photo means light. The first step in photosynthesis requires light. Chloroplasts (chlo-ro-plasts), the oval-shaped structures found in the cells of plant leaves, contain chlorophyll (chlo-ro-phyll). This green pigment absorbs the light that is necessary for photosynthesis to take place. Light and chlorophyll "pair up" to split water into its two parts, hydrogen and oxygen.

Now the plant is ready for the next step of photosynthesis. Stomata (sto-ma-ta), tiny pores in the leaves, take in carbon dioxide from the air. The carbon dioxide reacts with plant sugars and is split into its parts, carbon and oxygen. Now the plant is ready to synthesize (put together) all these elements. The chloroplasts combine the hydrogen with the carbon and oxygen to make the sugar, glucose. Extra oxygen is made, too. The stomata release this gas, that is so necessary to people and animals, into the air. So, every time you breathe, thank a plant!

Questions to discuss as initiating questions and/or as comprehension checks after completing the entire Photosynthesis packet:

1. Why is photosynthesis important?

2. What structures on a plant are needed to carry out photosynthesis?

3. What must a plant have for photosynthesis to take place?

4. Why are plants important to the food chain?

5. Why are companies becoming interested in trees?

6. What would happen to life on Earth if plants suddenly stopped performing photosynthesis?

Photosynthesis is not just for plant physiologists! Today, many businesses are interested in plants and trees. That's because of the carbon credits they can earn in exchange for helping to offset the effects of emitting harmful gases into the atmosphere.

Plants have been called the "lungs of the Earth." Photosynthesis, the complex chemical process that produces oxygen for us and food for plants, balances the gases of our atmosphere keeps air clean. Because of photosynthesis, plants are the anchor of all food chains on Earth. Everything either eats plants or eats an animal that eats plants. You may want to make or discuss food chains with your students and observe how they all are dependent on plants. That is just one reason why this natural plant process has been called the most important biochemical process on Earth.

Photo and Synthesis

In simple terms, photosynthesis is the way green plants make food. In this process, plants use light to convert water and carbon dioxide into the simple sugar, glucose. This is food for the plant. More importantly, it is also the basis for all food for humans and animals. All organisms depend on glucose, but plants are the sole producers of this life-necessary food. Each year, green plants produce about 30 metric tons of this carbohydrate for every person on Earth!

It may be helpful to break the word photosynthesis into its two main parts, photo and synthesis, in order to help your students understand this complicated process. It is also important to stress that scientists don't know everything about this biochemical reaction yet. Many studies are still being done around the world.

In very simple terms, plant physiologists divide the photosynthesis process into two steps, one requiring light while the second step involves a combining of chemicals and elements. Before you begin, you may want to review the chemical formula for oxygen ([O.sub.2]), water ([H.sub.2]O), and carbon dioxide (C[O.sub.2]).

The word-part, photo comes from the Greek and means light. The first step in photosynthesis requires light. Chloroplasts, the oval-shaped structures found in the cells of plant leaves, contain chlorophyll. This green pigment absorbs the light that is necessary for photosynthesis to take place. Light and chlorophyll "pair up" to split water into its two parts, hydrogen and oxygen.

Now the plant is ready for the next step of photosynthesis. In this step, the plant synthesizes (puts together the parts) to make food and release oxygen. Stomata, tiny pores in the plant, take in carbon dioxide from the air. The carbon dioxide reacts with plant sugars and is split into its parts, carbon and oxygen. Now the plant is ready to synthesize all these elements. The chloroplasts combine the hydrogen with the carbon and oxygen to make the sugar, glucose. Extra oxygen is made, too. The stomata release this gas, that is so necessary to people and animals, into the air. So, every time you breathe, thank a plant!

As your higher-level students read about this biochemical process, we suggest acting out the steps. Have your student "actors" make and wear signs that can be "broken apart" (water--H and [O.sub.2]) so they can recombine with other elements in the photosynthesis process.

Conditions for Photosynthesis

At this point, you may want to stop and discuss the conditions necessary for photosynthesis to take place. Emphasize that light, either sunlight or artificial light, is a basic component. Water is also required. Some plants such as corn and crabgrass have developed ways to thrive despite drought conditions. The stomata on these plants have the ability to partially close their pores. On hot days, this keeps water from escaping. This is why corn can thrive in hot, dry climates and crabgrass appears green in the heat of summer.

Your students may have noticed that some plants are not green. They may wonder if they conduct photo synthesis. Plants such as Indian pipe get their nutrients from organic material. Additionally, some bacteria make their own carbohydrates using hydrogen and the energy from inorganic compounds. This process is called chemosynthesis.

Your students may be interested to learn that there are devices designed to measure the rate at which a plant conducts photosynthesis. Our featured scientist in levels D and E, Dr. Hongjun Chen of the Wetland Biogeochemistry Institute, School of the Coast and Environment, Louisiana State University, uses such a device to measure the photosynthesis of cattails and saw grass in the Florida Everglades. He reports that these plants often stop performing photosynthesis around 4:00 p.m. The stomata close for the day! Scientists are studying the problem of overpopulation of cattails in the Everglades because this phenomenon is changing the ecosystem. Species that were dependent upon the saw grass could be forced to leave the habitat. This creates problems all along the food chain. Researchers are still working on the problem of why these cattails now seem to be flourishing in this area. Dr. Chen reports, "One hypothesis is that the fragmentation of the Everglades by the plowing of numerous canals throughout the area has changed the natural hydrology and, in many areas, increased the water level. Cattails flourish in greater amounts of water. The other hypothesis, on which we are focusing, deals with the permeating of sulfate and phosphorus from agricultural areas into the Everglades. Cattail growth can be fueled by higher levels of phosphorus in the water and land. In addition, sulfate may generate toxic hydrogen sulfide that can negatively impact saw grass, and promote cattail dominance."

Food and Photosynthesis

The simple sugar, glucose, that photosynthesis produces, is the basic energy source for all organisms. We need it, and plants use these tiny bits of sugar to make starch. They also use nutrients from the soil along with the sugar and starch to make proteins, enzymes, and vitamins. Plants use their food to make plant tissue or cellulose. This keeps plant cell walls strong.

Talk with your students about the many ways plants are food. Discuss the sweet taste of fruit, the starch of potatoes and beets and the healthy vitamins found in leafy vegetables such as spinach.

Clean Air and Photosynthesis

Today, with our concern about the ozone hole and air quality, photosynthesis has taken on an added importance in the business world. Discuss with your students how plants are necessary to keep the "perfect balance" of gases in our atmosphere. Emphasize that plants take in carbon dioxide and release oxygen. It is for this reason that many companies are now paying attention to forests. If they release carbon compounds into the air, they may need to balance this by planting or taking care of forests. Companies earn carbon credits for the photosynthesis that takes place in the trees they plant. This is a natural way to clean our air. This is one reason people have been concerned about the destruction of the rain forests and other vast stands of trees.

You may also want to discuss with students the concept of fossil fuels. Needed energy sources such as oil and gas are the decayed remains of organisms that relied on photosynthesis.

Falling For Photosynthesis

Your discussions may lead you to questions about autumn leaves. While much is still being learned about the factors that cause leaves to change colors, we do know that pigments in leaves, length of daylight, and weather conditions are the major factors in leaf color change. In spring and summer, chlorophyll is constantly produced in the leaves. This makes them appear green. As daylight decreases in the autumn, chlorophyll production slows down. It finally stops and the leaf's chlorophyll is destroyed. The leaf's veins (which carry water into and out of the leaf) gradually close off. A layer of cells forms at the base of each leaf. The clogged veins trap sugars in the leaf. A separation layer forms and the connecting tissues are sealed. Now the leaf is ready to fall.

Many factors influence the color of leaves. Some species tend to produce specific colors. For example, oaks turn brown, red, or russet while black maple trees sport bright yellow leaves. Weather is another factor. Warm sunny days and cool nights tend to produce more vivid colors. Rainfall and soil conditions also influence leaf color. Trees in temperate zones store sugars for the winter period as they do not have leaves to conduct photosynthesis.

Level E Photosynthesis: Making Necessary Food

The simple sugar, glucose that photosynthesis produces, is the basic energy source for all organisms. We need it, and plants use these tiny bits of sugar to make starch. They use nutrients from the soil along with the sugar and starch to make proteins, enzymes (en-zymes), and vitamins.

The next time you eat a sweet kiwi or orange, think of photosynthesis and the sugar it produced to make your fruit so tasty. Enjoying a big helping of mashed potatoes? Thank photosynthesis for making this starchy treat for you! You likely have heard that spinach is a vitamin-filled food. Your muscles and bones love this body-building food.

Photosynthesis: Making Valuable Air

You read that during the process of photosynthesis, plants take in carbon dioxide and release oxygen. As you know, we need oxygen to live. Too much carbon dioxide can mean trouble for our lungs. Green plants keep our air in balance. That is why many companies are now paying attention to forests. If they release carbon dioxide into the air, they may need to balance this by planting or taking care of forests. The trees take in the harmful gases released by factories, make food, and release the oxygen into the atmosphere (at-mo-sphere). Companies earn carbon credits for the photo synthesis that takes place in the trees they plant. This is natural way to clean our air.

Math

Using math to make environmental decisions--In an imaginary town called Forestville, there are 125 families, with four people in a family. These families each own 2 cars. They drive each car an average of 12,000 miles per year, and the cars get an average of 20 miles per gallon of gas.

Think about these facts and then answer the question, below:

FACT #1

5.159 pounds of carbon are emitted from burning one gallon of gas.

FACT #2

A mature tree consumes about 48 pounds of carbon per year.

How many trees does Forestville need to plant to offset the carbon generated from just the cars they drive?

Science says ...

Round your answer UP as you can't plant part of a tree!

Meet the Scientist

Dr. Hongjun Chen, Research Scientist, The Wetland Biogeochemistry Institute, School of the Coast and Environment, Louisiana State University

Hongjun Chen's studies focus on preserving the ecosystem of the Florida Everglades. He measures how saw grass and cattail uptake carbon dioxide to perform photosynthesis. This helps scientists learn why cattails are taking over this wetland. Overpopulation of cattails is unhealthy for the ecosystem. The animals that depend on saw grass for food and habitat could be forced to leave the Everglades for other food sources. The effect could cascade down the food chain from one species to the next. If something is not done about the spread of cattails, the Everglades will become an entirely different environment.

When Dr. Chen was a little boy, he was curious about how plants eat and drink. He knew that people have mouths, but plants don't. Later when he went to school, he learned about the process called photosynthesis. He thought plants were very smart and considered them man's good friends. When he went to college, he chose as his major, Soils and Plant Nutrition.

Dr. Chen says he enjoys working on plants and studying plant photosynthesis.

Vocabulary

Developing your language skills--Read these sentences about plant structures that are important to photosynthesis. Put in the correct punctuation such as quotation marks and commas.

1. Science said Leaves are important for photosynthesis because they collect light.

2. Are the cells that contain chlorophyll called chloroplasts asked WHY FLY.

3. Science answered The chloroplasts contain chlorophyll and absorb the light that is necessary for photosynthesis.

4. I believe roots are important because they collect the water that is needed for this process to occur stated FLY-pothesis.

5. Xylem transport water and minerals up the stem to the leaves added Science.

Writing In Science

Write a diamonte (di-a-mon-te) about plants and photosynthesis

A diamonte is a type of poem. It is in the shape of a diamond! It's easy to write a diamonte. Just follow the formula, to the left.

Line 1--1 noun or pronoun

Line 2--2 adjectives

Line 3--3 participles (verbs with -ing)

Line 4--4 nouns

Line 5--3 participles again

Line 6--2 adjectives

Line 7--1 noun or pronoun

Here is an example:

Tree Green, Leafy Flowering, Rusting, Standing Roots, Trunk, Branch, Leaf Growing, Waving, Budding Strong, Majestic Oak

Now, write your own diamonte.

Weekly Lab

You need: 4 cups, soil, pea seeds, paper towels, water, glass jar to fit over a cup, a ruler, paper and pencil

Step 1: Put pea seeds in a damp paper towel. Be sure the paper towel stays damp by keeping it watered with warm water.

Step 2: When the seeds begin to germinate (ger-mi-nate) (a little hook will appear), fil the cups with soil and plant the pea seeds.

Step 3: Put two cups in the sun, and put the other two cups in a dark closet. Keep both cups watered.

Step 4: At the end of ten days, compare the plants. Measure each plant. Compare the colors of the plants that grew in the closet with the plants that grew in the sun. Take one of the plants that grew in the sun, out of the cup. Examine its roots. Do the same with one of the plants that grew in the closet. Record your results.

Step 5: Place the jar over the plant that was grown in the sun. Put it back in the light. Watch it for several days. Record what you observe.

What do you see? Why do you think this occurred?

Science says ... Here is a hint. This process is called transpiration (tran-spi-ra-tion)! (1)

Adult Supervision Recommended

How can we show that plants need light and they give off oxygen?

(1) Look on the bottom of page 3 for the answer.

WEEKLY LAB Answer: Transpiration is the process whereby water vapor is giving off by a plant as it exchanges oxygen for carbon dioxide.

Weekly Resources

Helpful Sources for Planning Your Science Weekly Classroom Activities

Recommended Resources

* Batten, Mary. Aliens From Earth. Atlanta, GA: Peachtree Publishers, 2003.

* Fowler, Allan. Energy From the Sun. New York: Grolier Children's Press, 1997.

* Gerber, Carole. Leaf Jumpers. Watertown, MA: Charlesbridge Publishers, 2004.

* Maestro, Betsy. Why Do Leaves Change Color? New York: Harper Collins Publishers, 1994

Internet Resources:

http://www.education-world.com/a_lesson/lesson024.shtml has an informative article and activities about color change of leaves and photosynthesis.

http://www.enchantedlearning.com/subjects/plants/plant/ contains "child friendly" information about plant structures and their functions.

http://www.missmaggie.org has a wonderful interactive dichotomous key in their "Herd of Elephants, Part 2" mission pack. Click on the microscope and let students learn how scientists use this tool to identify plants.

Level Pre-A

Main Concepts: Plants are an important food source for people and animals. They also help keep our air clean.

Picture Activity

Draw students' attention to the children and rabbit eating carrots. Ask students what plants they like to eat. Ask them what helps plants to grow. Point out the sun and water. Explain that plants use sunlight and water to make their own food.

Vocabulary

Say the word, plant. Raise your arms (like a growing plant) when you say short a. Go around the room and say any names of children that contain short a. Ask children to think of other words that may contain this sound. (You can hold up a black crayon or an apple as clues.) Ask children what letter says this sound. Have children put the letter a on each line and read the words together.

Weekly Lab--What do plants need?

I always like to use easy-to-grow plants like philodendrons for classroom experiments. They are more tolerant of the over- and under-watering that children may do, and their big green leaves are easily observed if you are doing the experiment as a class.

After the week is over, compare the two plants. You could have students make comparative pictures of what the plants looked like.

To extend this activity, put the bagged plant in the sun. Ask children to predict if the plant will "get better" and start making its own food.

Math--Picking up math facts

Have children cross out the number of carrots so they can visually see the taking away of the number. After children have finished, tell them to look at the numerals they have written to be sure they are facing the correct way. All the numerals they will write are printed on the page, so instruct them to match their numerals with WHY FLY's problems.

Writing in Science

Talk about plants children like to eat. Have them close their eyes and clench one fist as a pretend microphone. As you pose the questions in the activity, have them whisper the answers into their microphones. When finished, give them sheets of paper to write and illustrate their stories. You may even want to enlist the help of a family member, and have a plant snack time where children can share their favorite plant foods!

Bringing it Home--Making food chains

After finishing this activity, encourage children to make their own loops to illustrate other food chains. Talk with them about how plants are the basis for all chains.

Level A

Main Concepts: Plants make their own food by using light, air, and water. They are an important food source for people and animals. They also help keep our air clean.

Picture Activity

Ask children why the plant in the picture has a hand and mouth. Discuss how the artist used these features to make the point that plants use water and air to make their own food. Question students as to why the the boy is holding a carrot. Lead the class to the understanding that all animals depend on plants for food. Ask the children to take a big breath of air. Discuss how plants give off oxygen when they make their food. This is the air we need. Write the word, oxygen, on the board. Draw attention to the short o and e in the word. Review the sound of x. Challenge children to write the word, bring it home, and impress their families with their ability to read and write such an important science word!

Vocabulary

Ask children to whisper read the words in the Word Bank, either to themselves or to a partner. Ask them to match the words to those in the article on the front page.

After completing the exercise, you can extend this activity by having children work with a partner to act as a plant and scientist. One child's body can represent parts of the plant (i.e. arms as leaves, feet as roots) and the other child can be a scientist who explains how these parts use air, light, and water to make food.

Weekly Lab--What do seeds need?

Before beginning the experiment, ask children to make a hypothesis as to what the results will be. You can write, "I hypothesize" on the board and use this as a writing activity.

After the experiment is completed, you can extend the activity by putting the seed that was in the dark place, into the sun. Make predictions and observe what happens.

Math--Fractions--Parts of a whole

Before doing this activity, draw 2 drops of rain on the board. Write the numeral 2 on the board. Circle 1 of the drops. Ask children how many drops you circled. Write 1 above the 2. Talk about the 2 drops as being a whole. Show them that the I is one part of the whole. Do other examples as needed. Discuss common items that are divided as fractions such as pizza. Challenge them to look at their pizza the next time they eat one. Find out how many slices there are. Have them write down how many slices they eat. Keep a classroom chart of this fractional information.

Writing in Science--Science poems

Write the word, TREES, vertically on the board. Point out the sound of each letter. Then read the acrostic poem together. Discuss how each letter is the first letter in a description of trees. Tell the children that this is a type of poetry. Give them long sheets of paper and have them copy plant-world words on the paper to write their own poems. You may want the class to work as poet-partners to accomplish this task.

Puzzle--A very BIG word puzzle!

Children love to read big words. Some of your children will have heard of the term photosynthesis and will delight in "reading" the word. After children solve the puzzle, use the word as a phonics lesson. Discuss the sound of ph, the word photo, and compare the sound of y in it to the y in oxygen.

Bringing it Home--Making food chains

Read the directions together (The words are Dolch words that most first-graders likely know at this point in the year). Talk with them about how plants are the basis for all chains. After finishing this activity, encourage children to make their own loops to illustrate other food chains.

Level B

Main Concepts: Plants make their own food by using light, air, and water. They are an important food source for people and animals. They also help keep our air balanced and clean.

Vocabulary--Fascinating facts

Before beginning, have students silently read the sentences. Encourage them to look back to the article on the front page to find the correct words. We have purposefully not included a word bank to encourage students to develop the habit of checking the article for facts--an important skill children often overlook when taking standardized tests.

Answers:

1. Plants use the gas, carbon dioxide in photosynthesis.

2. The atmosphere must be in balance.

3. Tiny pores take in carbon dioxide.

4. Plants release oxygen. This helps us breathe.

5. Roots help the plant take in water.

6. When plants make their food it is called photosynthesis.

Weekly Lab--What do plants need?

After completing the lab, encourage children to write in science notebooks about their results. Have them make predictions as to what will happen to the covered leaves after the paper is removed. Continue the experiment and make further observations.

Math

Plants lend themselves to beginning multiplication problems. If children are having difficulty with the concept, encourage them to use pictures. Children needing enrichment can write their own math problems.

Answers:

1. 20

2. 21

3. 24

Writing in Science

Here is a way to integrate a needed writing skill and science concepts. Discuss the parts of a friendly letter with the class before they begin the writing exercise. (They are listed in the yellow box on the student's level.) Have children read their letters to the class or in small groups.

Puzzle--Secret code puzzle

Answer: lungs

Here is a puzzle with a twist: children have to serve as editors and find incomplete sentences. Discuss why plants are called the "lungs of the Earth."

Bringing it Home--Around the year--making predictions

Talk about fall leaf colors. You may want to read the book, Leaf Jumpers by Carole Gerber. This cute poem highlights how different tree species tend to turn specific colors in autumn. Encourage children to look at trees in their own neighborhoods and parks and save their predictions to check them when the leaves turn color.
Tree Usual Color

Oak Red or Brown
Red Maple Bright red
Aspen and Yellow Poplar Yellow
Beech Tan


Level C

Main Concepts: Plants make their own food by using light, air, and water. They are the anchor of all food chains on Earth. They also help keep our air balanced and clean.

After reading the front-page article, help students develop an important nonfiction comprehension skill by having them go back and answer the questions posed by the heading questions.

Vocabulary

Integrate science and a troublesome language arts area for third-graders by having them "become detectives" and find the homophones that are used incorrectly in these sentences.

Answers:

1. The leaves are the major organs for photosynthesis.

2. Carbon dioxide enters the leaf through tiny pores called stomata.

3. There are tiny cells in leaves called chloroplasts.

4. It's important to know that root hairs take water from the ground.

5. Water is transported by structures called xylem.

Weekly Lab--Do plants move?

I like to use easy-to-care-for plants such as philodendrons for plant experiments. Encourage children to sketch their plants each day. You may even want to take measurements at the end of specific time periods.

Math--Companies plant plants!

Show children how they can use the information in the article to solve math division problems. Make the point that real-life math doesn't always have problems laid out for them! They often have to search for the information to solve problems. This activity allows practice of this skill.

Answers:

1-8; 2-6; 3-9

Writing in Science--Write a science poem!

Haikus are a great way to motivate children to look more closely at syllabication. You may want children to work as partners to create their poems. Make a bulletin board of their work.

Note: How many children noticed that the directions are a haiku?

FYI--Further Your Interests--Geography and Science

Talk with your students about invasive species and native species (Refer to Science Weekly, Volume 21, Number 5--Grass.) Encourage discussion of how animals that use saw grass for food and habitat may disappear from the Everglades. This will change the ecosystem.

Puzzle

Answer: crabgrass

Crabgrass can close their stomata. This explains why it is green on hot summer days while the rest of the lawn is dry and brown. Corn also has this ability.

Level D

Main Concepts: Plants make their own food, glucose, by using light, carbon dioxide from the air, and the components of water. They are the basis of all food chains on Earth. They help keep our air balanced and clean.

Vocabulary--Running on about photosynthesis

Integrate language arts objectives and science by having students identify and edit run-on sentences.

Answers:

1. A plant's leaves are the major organs for photosynthesis. This is because they have a large surface area to take in sunlight.

2. Chloroplasts, cells in leaves, contain chlorophyll. It is a green pigment that takes in light,

3. (circle around it) Roots anchor a plant and help it take in water.

4. (circle around it) A stem supports the leaves and places them in good light.

5. Xylem transport water up the stem to the leaves. Phloem transport sucrose around the plant.

6. There are tiny pores called stomata. They take in carbon dioxide.

Writing in Science--Writing science poetry

After children write their poetry, make a bulletin board to showcase their work. Rather than individual pictures, why not have the class paint a mural highlighting the importance of plants to Earth. The planning of such a work will result in a great science discussion!

Here is a cinquain about trees.

Maples Beautiful leaves Rustling, growing, budding Making food and cleaning our air Helpers

Now write your own cinquain.

Math

Talk about the necessity of plants (trees) to life on Earth.

Answers:

1. 3,000,000 miles

2. 150,000 gallons of gas

3. 150 acres

Meet the Scientist--Dr. Hongjun Chen

Discuss the concept of native species, exotic species, and invasive species with the class. (Refer to Science Weekly, Volume 21, Number 5--Grass.) Talk about how invasive species can hurt ecosystems. You may want to have children write an article about a typical day as a researcher in the Everglades. Encourage them to use good descriptive and sensory words to "paint" word pictures of such things as an airboat ride, the animals that may be seen, and the work that is done in the heat of the day.

Weekly Lab--Find out if plants move!

I like to use easy-to-care-for plants such as philodendron for plant experiments. Encourage students to record and sketch their observations. They may want to measure change and graph this information.

Level E

Main Concepts: Plants make their own food, glucose, by using light, carbon dioxide from the air, and the components of water. They are the basis of all food chains on Earth. Because they help keep our air balanced and clean, trees can now earn carbon credits for companies in exchange for helping to offset the pollution that the factories put in the air.

Vocabulary--Developing your language skills

Answer Key:

1. Science said, "Leaves are important for photosynthesis because they collect light."

2. "Are the cells that contain chlorophyll called chloroplasts?" asked WHY FLY.

3. Science answered, "The chloroplasts contain chlorophyll and absorb the light that is necessary for photosynthesis."

4. "I believe roots are important because they collect the water that is needed for this process to occur," stated FLY-pothesis.

5. "Xylem transport water and minerals up the stem to the leaves," added Science.

To extend this activity, make a class list of synonyms for said.

Writing for Science--Writing a diamonte about plants and photosynthesis

Have students paint a mural and then tack their diamontes around it.

Math--Using math to make environmental decisions

(Note--Although scientists use the metric system, Americans generally use miles and gallons when discussing driving. That is why we have used the common American standard in this problem.)

Help students to make a plan to solve the problem.

Answers:

Step 1--How many cars are there? 2 cars per family - 125 x 2 = 250

Step 2--How many miles are driven each year by these cars? 250 cars x 12,000 miles per year = 3,000,000 miles.

Step 3--How many gallons of gas are used each year? 3,000,000 divided by 20 mpg = 150,000 gallons of gas

Step 4--150,000 x 5.159 pounds of carbon per gallon of gas = 773,850 pounds of carbon per year.

Step 5--773,850 pounds of carbon divided by 48 pounds of carbon per tree = 16,121.875 trees.

Step 6--Round 16,121.875 to 16,122 trees needed to offset the carbon generated by the cars in the town.

Meet the Scientist--Dr. Hongjun Chen

See TN--Level D.

Weekly Lab

Be sure children form a hypothesis and record their results. The tiny water drops on the inside of the jar are an example of transpiration. This is the excess water that is given off by plants in the process of performing photosynthesis. Discuss the concept of transpiration with students.

DID YOU KNOW??

28 million acres of tropical forests are cut and burned each year.

DID YOU KNOW??

Each year, green plants produce about 170 billion metric tons of extra carbohydrates.

DID YOU KNOW??

Each year, green plants produce about 170 billion metric tons of extra carbohydrates.

DID YOU KNOW??

28 million acres of tropical forests are cut and burned each year.
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Date:Sep 1, 2005
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