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By absorbing light and taking in water and carbon dioxide, the leaf will produce excess oxygen and food the plant needs for growth. Light is absorbed by leaves and differences in surface area exposed to light can change the rates of photosynthesis.
Carbon dioxide is absorbed into a leaf through stomates, which are found on its surface. Water also is lost from a leaf through its stomates so plants with a large surface area can lose large amounts of water. By the end of the discussion, students should come to see that in general, differences in leaf area can affect photosynthesis and therefore, the production of oxygen and food a plant can generate.
Again, students should explore geometric shapes that most closely resemble the real leaves in your classroom. Here is another great opportunity to think about either the overall shape of a leaf or break a leaf into various geometrical shapes and then estimate leaf surface area by calculating the area of the related geometric shape s. Does the geometric shape s over- or under-estimate the area of your real leaves?
While the students still have real leaves available, divide students into groups and hand out different photocopied leaves to the groups of students. Each group should receive the same species of leaves so areas can be compared later in the activity.
Ask students to find the area of their leaves using square centimeters and record their solutions and methods. Students should use the Surface Area of a Leaf student sheet for this exercise. Provide rulers, string, pencils, scissors, etc. Encourage students to use whatever materials they need to find the area; however, let them try to figure out the surface area of their leaves on their own.
After students have estimated the surface areas of their leaves, they should compare their data and solution methods with the other groups. For lower learners, students can trace the leaves on centimeter grid paper. Then they should outline the leaves in a dark color to make it easy for them to see. Next, students can count how many whole grid squares were in the leaves. Then they should count the number of partial squares and divide that number in half to get an approximate number of additional square centimeters.
Please see the examples of this process in the Surface Area of a Leaf teacher sheet. Discuss as a whole class the strategies used and the merits of each strategy. A discussion about the importance of estimation and measurement precision should ensue. One way to assess student understanding would be to ask them to do a Frayer Model again to graphically organize knowledge into four sections, including: Finally, you could ask students to describe two methods for finding the surface area of a leaf and describe two types of leaves that would be best measured using each of the two methods.
This lesson can be extended to find the surface area of a leaf using proportional reasoning. For higher learners, you could have students photocopy a leaf onto a sheet of paper, cut it out, and weigh the leaf using a balance scale.
Then, they should cut a rectangle out of the same type of photocopy paper used for the photocopy of the leaf and weigh the rectangle. Students should continue to cut off strips of the rectangle until the rectangle has the same mass as the photocopied leaf. The use of a rectangle allows students to quickly calculate the area of a familiar shape.
Now that the mass of the two objects is known, as well as the area of one object, students can find the area of the leaf in a more precise way using proportional reasoning. Students can then compare their original area measurement with that of this more precise measurement.
For higher learners, a possible extension is to have students draw leaves on grid paper at normal 1X , 2X, and 0. Changes in leaf surface area increase or decrease by the square of the increase or decrease in length.
Therefore, a leaf that is drawn twice the size in length 2X will have a surface area that is four times the original surface area.
This provides an excellent way to demonstrate the mathematical relationship between length and area. Then have students measure the leaf length and surface area at each size. What is the relationship of length to area as size increases? Fractal Dimensions of Leaf Shapes is an activity in which students can analyze leaf shapes in terms of fractal geometry. To take this lesson further, a mathematical modeling extension could be done with students to determine the surface area of a canopy of leaves on a tree.
Once we have this information about tree canopy surface area, how could we use that information to determine the weight of the entire canopy on that tree? Tools students may need for this task include access to the trees the leaves came from, even if they simply have a photo of a tree. Trees on the school grounds could potentially make good subjects for this research project. What is the surface area of all of the leaves on all of the trees at school?
What is the weight of all of the leaves in these tree canopies? Do different tree species have differing total leaf surface areas? Do older trees have differing total leaf surface areas than young trees of the same species? Ask children to describe his or her leaf. What color is it? What shape is it? What do the veins look like? Do there appear to be holes on the surface? Encourage children to draw their leaf on the My Leaf Recording Sheet, paying close attention to the veins of the leaf.
Let children use a magnifying glass to look at the veins of the leaves. Point out that the veins are the circulatory system of the plant, much like the veins in our own body that can be seen on the backs of our hands and the tops of our feet.
Explain that the veins carry food to the plant. Let children record their leaf on the My Leaf Recording Sheet. Let children trace around their leaf with a pencil. Next, let them use a Sharpie marker to trace the pencil marks and draw the veins on the leaf. Last, have them color the leaf with water colors to look like the real leaf. The Easter Egg Farm. Join our mailing list Preschool Activities:.
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