This page last changed on Aug 13, 2007 by cmcintyre.
Note: Sections I and II (Standards) are addressed in separate doc (see: http://confluence.concord.org/display/UDL/Instructional+Objectives+for+the+Plant+Unit)
III. Current Student Conceptions on....
Students think that soil, water and sunlight are food for plants.
[currently working on collecting more]
IV. Design Rational for this Unit
The idea with this Unit is to take on the idea that plants don't eat food but make their food. In the first activity, they will be identifying and observing the different plant structures (roots, stems and leaves) and how they obtain water, sunlight and carbon dioxide and how that is measured in food production. In this activity, the students will be manipulating the parts of the plant and the environmental conditions will be constant. This is to learn what functions these parts have.
In activity two, we need to prove to the students that food is actually manufactured inside the plant. This is not an easy thing for students to understand. Students will perform the starch test on all parts of the plant (stems, roots and leaves) to figure out if food is produced and where it is stored.
At this time students now know that a plant takes in sunlight and carbon dioxide through its leaves, water through its roots and stores food in both its roots and leaves. But the next question raised is 'does it really need all of these things to produce food'? In activity three, students design an experiment to answer that question. In this experiment students are changing the amount of water and sunlight plants receive while keeping the amount of carbon dioxide constant. They will be measuring growth of the plant. Growth implicitly assumes that food is being produced in this experiment but will be unpacked in the following activity.
By this time, we have proven to students that plants take in water, carbon dioxide and sunlight and have food stored in their roots and leaves. They have learned that water, sunlight and carbon dioxide are all needed for plants to grow, but we need to make the next step to show students the connection to food production. In activity four, students will go back to a similar model where the plant will be the constant and they will be able to manipulate the water, sunlight and carbon dioxide to see how much food is produced. This is where students can understand why all three materials are important and experience that just adding more water will not get you more food. Or just getting more sun will not get you more food.
V. List of Technology Components
- 1 Time lapse video showing sunlight, water and air
- 1 Flash animations 'build your own plant' with food-o-meter
- 1 Flash animation plant stays the same, students manipulate the environment.
VI. Distinctions we are making for grade 3-4
- When talking about plants making sugar - we will just call it food.
- When needing to talk about carbon dioxide - we will just leave it as air.
VII. Design Plan with Storyline
Driving Question - What do plants eat?
o Exploration 1 (computer) Why do plants look the way they do?
Identify the structures of a plant their functions. Leaves = take in sunlight and carbon dioxide.
Roots = take in water
Stems = transport water to the leaves.
Identify that plants need sunlight, water and carbon dioxide to make food. Plants need water, sun and carbon dioxide to make food.
Predict how the functions of multiple structures. Different leaf structures collect more sunlight then others, different root structures work for different environments.
Part 1: Observing a Plant Grow
Students observe plants receiving water and sunlight. Over the time period they see the plant growing.
Questions: (goal - to capture student conceptions at this time)
1. What is happening to the plant?
2. Do you think water is important for the plant? Y or N
3. If yes, why do plants need water?
4. Do you think sunlight is important for the plant? Y or N
5. If yes, why do plants need sunlight?
Answers to these questions should be saved to be brought back to when the answer the driving question at the end of unit.
Part 2: Build you own Plant
Students are given one environment when the page opens up and three different choices for each of the plant parts (leaves, stem and roots). Students pick one of the three choices they get leaves, stems and roots. The image they created appears in the environment picture. They press start and the plant structures perform their functions (the water in the soil goes up the root system and into the stem, the leaves on the plant collect sunlight) and show how much food they are producing [need to add the food-o-meter].
This table describes the actions that will happen if students select the different options.
[Once we figure out biomes then we can figure out kinds of leafs, stems and root systems and their behavior in the model]
Sunlight Carbon Dioxide Water
Sunlight Carbon Dioxide Water
Sunlight Carbon Dioxide Water
At the end of the activity make sure to revisit the sub question - Why do plants look the way they do?
Timelapse video of plants growing and thriving.
Build your own plant
Play up the differences in the various structures (ex. big leaves, versus small leaves versus waxy leaves)
Make an observation that even though they are different they all do the same thing.
o Exploration 2 How do we know that plants make their food?
Develop a definition of what food is for plants. Food for plants are starches.
Identify where in the plant food can be found. Roots and Leaves
[I understand that there are concerns with using iodine and the complication of the steps. I have been searching the web for alternatives, but have not found any. I have found some virtual starch labs. Is this something that can be more of a teacher demo or we can film for the students. I feel like if we really want to talk about plants making their food, we need to prove that plants have food inside them.]
Taken from: 101 Great Science Experiments (see Appendix A)
a. Get a full grown plant with lots of leaves.
b. Tape plastic around some leaves. Place the plant in the light for 2 days. Then pick a wrapped leaf and an unwrapped leaf.
c. Warm water and dip both leaves in the water to stop any chemical reactions happening in the leaf.
d. Warm Ethenol in a water bath and dip both leaves in the Ethenol to remove any chlorophyll.
e. Place the leaf on a plate and drop a few drops of iodine. If the leaf turn bluish - black then, food was present.
f. Do the same for a root.
g. Do the same for the stem.
[this is my adaptation to the lab, I don't think we will have to do the alcohol step for the root since it should not have any chlorophyll but I need to try it out.]
Wrapped Leaf Food present
Unwrapped Leaf No Food present
- talk about roots and leaves as storage places for food. Ex. veg with roots like the carrot, could talk about the venus fly trap here and how it eats insects and makes its own food.
o Exploration 3 Can a plant survive without water and sunlight?
Develop and test an hypothesis about the needs plants have to make food. Ex. Plants only need sunlight to survive?
Support their hypothesis from data they collected in their experiment. Ex. Plants cannot survive just with sun.
o Exploration 4 (computer) Do plants actually eat?
Students will test out predictions about how leaves, stems and roots affect the amount of food produced. Not all options for leaves, stems and roots are good for all conditions.
Students will explain the relationship between sunlight, carbon dioxide, water and food production in plants. Plants need all three sunlight, carbon dioxide and water to produce food.
Students will explain that plants don't eat, they make their own food. Plants don't actually eat, they make their own food called starch.
o Wrap Up
Revisit the Driving Question