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Comparing leaves


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Comparing leaves

  1. 1. Spice Summer academy -Prague, Czech Republic – Friday 26 to Sunday 28 August 2011 1
  2. 2. ObjectiveStudents will learn that a tree can often be identified just by looking at its leaves but this task will be easier if you also look at its bark , fruit, flower, bud..Content involved basic study of the leaves basic study of the barks basic study of the photosynthesis use of the identification tree leaf keySkillsObserving, gathering information, critical thinking, drawing classification, communication… 2
  3. 3.  Which teaching material needs to be used? Documents about trees and leaves, pencils, markers, paper, drawing paper, glue… camera. Which key facts do students need to know before the start of the GP? Nothing special What are the aims ? Students will be able to recognize a tree thanks to its leaf , bark, flower, fruit, bud… They will learn that each type of tree has distinctive bark and unique leaves and fruit and these characteristics can be used to determine the species of the tree. They also will learn to work in group. How much time is involved in preparing and teaching this GP? 4 lessons (4 x 50 min) 3
  4. 4. How to implement this GP resource?1/ Take the classroom outside in the neighborhood ( the teacher has selected some deciduous trees) - each student collects and observes one leaf from a deciduous tree - they make rubbings of bark patterns and color them2/ In the class a/ - The students discuss and compare the different bark patterns to find classmates with the same one - The students with matching bark pattern should be grouped together - The different groups try to match bark to tree by the aid of documents and a tree identification guide. b/- They compare leaves to find classmates with the same leaf - The students with matching leaves should be grouped together - They discuss and try to identify to which tree their leaf belongs with the aid of the identification key c/ - They put all the different type of leaves on a table and they try to classify them (simple, compound, lobed, with teeth, opposite, alternate) d/ - They do a synthesis with the help of the teacher. The teacher has prepared a « student’s guide » with all the important information the students must remember: 4
  5. 5. 3/ Outside : -The students are divided into four/five groups . Each group chooses a leaf. - They go outside with their leaves, documents, paper, pencils, camera … - They look for the tree corresponding to their leaf. - They draw , observe and collect all the material corresponding to their tree. .4/ In the class : Each group has to discuss to plan a poster (or a reproduction ) of their tree with the material collected and presents the tree to their schoolmates 5
  6. 6. We began to implement our GP at the end of April Age of the students: 12/13 years old 6
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  9. 9. The students arebroken into four/five groups. Each grouprepresents adifferent tree 9
  10. 10. Tree type/shapeThey make a detailed free hand drawing of the tree and a picture 10
  11. 11. The Bark They make rubbings of bark patterns. They write the color, the structure, the smell of the bark 11
  12. 12. The leaves- flowers-fruitThey take a branch with several leaves on it , with flowers and/or fruit 12
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  21. 21.  What about the evaluation of the students’ achievement and of this GP? The students - they feel a real sense of « achievement » - they look at nature and especially at trees in a new light - they set more value on trees and on nature - they are able to recognize some trees - they study having fun I find this GP very interesting. It seems childish but it is not! You can go deeper and mention other topics. For example you can: 1. repeat that exercise in the different seasons and observe the transformations 2. study conifers 21
  22. 22. 3. mention that even when a tree is dead, it is full of life thanks to the activity of bacteria and animals ( insects , birds, squirrels…). Dead trees have features that live trees don’t have . When the tree decays completely it returns nutrients to the soil. When limbs or trees fall into the water (lake, stream) they make home for fish . When limbs fall on the ground , animals make homes in them.4. teach something about « photosynthesis ».Students will learn how trees produce their own food and how every part of the tree contributes to the process of making and distributing food.5. teach that although we use trees for many things in our daily lives, if we plan carefully, we’ll never run out of trees6. approach the Greenhouse Effect and the causes of Global Warming. All plants absorb carbon dioxide, but trees are best. They are considered nature’s most efficient “carbon sinks.”….. And many other topics…. 22
  23. 23. What about the evaluation?1/ The teacher evaluates the realization of the poster and the oral presentation of each group. The answers to their schoolmates’ questions are also evaluated2/ The students must be able to associate a tree to its leaf 23
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  25. 25. 1- The petiole ( + stipule , bud )The petiole of a leaf can be:  long  short  rounded  flatSome leaves have no petioleThe stipule : small leaf-like structure at the base of the petioleThe bud : a baby potential branch between the petiole and the stem 25
  26. 26. 2- The bladeThe leaf blade varies greatly in shape and there are terms todescribe its general shape •apex •base •margin •veins 26
  27. 27. If two leaves arise at a node, the If only one leaf arises at a node, theleaves are said: leaves are said: Opposite leaves  Alternate leaves 27
  28. 28. Simple leaves : one unit Simple leaf with teeth Simple lobed leafSimple leaf without teeth Compound leaves: numerous small parts Palmate compound leaf Pennate compound leaf 28
  29. 29. Basics of tree identification Here are some clues that you will need to examine, to be able to identify a tree: tree type/shape leaf bark bud fruit TREE TYPE -- Tree or a shrub? Deciduous or Conifer?? . LEAF - Are the leaves simple ? Without teeth? With teeth? Lobed? - Are the leaves compound? Palmate? Pennate? - Are the leaves arranged in an opposite pattern or alternate pattern? BARK --What color is the bark? Is it rough or smooth? Is it thick or thin? Does it have a smell? …. BUD -- look at the shape, the color…… FRUIT – the observation of fruit shapes makes them useful especially when leaves look alike.After collecting all of your clues, you should use the leaf key to verify the tree species . 29
  30. 30. Identification key 30
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  32. 32. Photosynthesis changes the energy from the sun into chemicalenergy, splits water to liberate O2, and fixes CO2 into sugar 32
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  34. 34. This GP has also been implemented in their class by:Sonja Artac - Slovakia Bento Baptista – Portugal Carlos Cachado – Portugal Herman Morgenbesser – Austria Irena Skolilova – Czech Republic 34
  35. 35. OPEN DISCUSSION-1/ Teachers who implemented this GP• Was it problematic to implement a GP that someone else has created?• What has been modified to implement it in class? - curriculum adaptations - students working habits ( more discussions, group work versus individual• Did the test group know that they were part of a project?• What are the benefits and problems encounterd by the teachers and the students• Are you considering using this GP again in the future ? Why ?-2/ Other teachersHow could this GP be implemented in your country: - How would you have done it ? - What problems would you find? - What does not fit in your country? - What does fit in your country? ……. 35
  36. 36. www.idbbxl.comInstitut Don BoscoAvenue du Val d’Or, 90 d Tina Michetti1150 Bruxelles tinamichetti@hotmail.comBelgium 0032 494 69 30 10 36