Teacher's Pages
ACTIVITY SEVEN: Creating Models of Bean Plants
ACTIVITY 7- STUDENT'S PAGE
(It may be helpful to view the student page alongside this teacher
page.)
Purpose:
This activity challenges students to use their new ideas
about the embryo getting food from the cotyledon to create a model of how an embryo gets its food to
begin to grow. The activity enables you to assess students' ways of understanding the idea that there is
food stored in the cotyledon. What do they think that food comes from? Is it water taken from the soil? Or
is it food that has been stored in the seed?
Many misconceptions will persist. But students will later have a
chance to revise this model after the concept of photosynthesis has been developed.
This activity also introduces and explores the concept of a
"model."
Teacher Role: Make sure that students are clearly using the idea
that the embryo has to get food from the cotyledon. Make sure that students are clear that there is debate
within the class about where that food comes from, so we will have to continue to explore our question
about how plants get their food. Give feedback to help students analyze the skits as models of what is
happening in real plants. Encourage students to keep an open mind and to consider alternative
explanations.
Materials:
Ideas for props :
Use colored poster paper to create large representations of :
2 cotyledons (cut out one cotyledon from each piece of poster
board and write "cotyledon" in large letters)
A watering can
A sun or light bulb (although light is not really needed for the
seeds to germinate, the students
usually insist on having this prop at this point in the unit)
A sign that says "EMBRYO"
Alternatively, you can let students create their own props from
materials you provide (this will increase the time needed to create the skits).
KEEP IT SIMPLE! The skits work best when the props are kept
simple. For example, a student could act as the embryo and be curled up between the 2 poster board
cotyledons.
Advance Preparation:
1. Create props or gather materials for prop making.
2. List on a chart or overhead transparency the requirements for
the skit models here
FRAME
TEACHER SAY AND DO, STUDENT RESPONSES AND INTERPRETING STUDENT
RESPONSES
Explain the model making activity and rules by reading or talking about p. 24.
Emphasize the importance of creating an accurate model based on what they know from
their experiment. You could suggest that students try to act out what was happening in the 4 different
conditions in the experiment.
Can we make our own props?
Students will be more motivated to create an interesting skit if they perceive this as a
creative opportunity. Props are important in getting students engaged, but if they become too elaborate they
distract from the purpose of the activity.
Why do we have to have everybody speak?
Shy students might not want to participate and /or more assertive students might take over all the
planning and acting. This rule is essential for getting all students involved in the planning and
thinking process, not just the performance.
What do you mean about "an idea about how the food gets into the cotyledon?
Most students who say "the embryo gets food from the cotyledon" are still thinking about
the embryo getting food from the water and minerals in the soil. They think the food in the cotyledon
was soaked up from the soil. THIS TASK SERVES AN ASSESSMENT
purpose for the teacher. It will be returned to later in the unit.
What do you mean about asking a question?
Students who are used to science providing answers may need support in understanding that
good scientists are always asking questions and challenging ideas and observations.
ACTIVITY
1. Allow students time to plan and practice their skits. This
usually takes the bulk of one class period.
2. Before beginning the presentation of the skits, pass out the
Bean Model Presentation Feedback Forms here.
3. After each group's presentation, have students spend some time
writing down their feedback on the forms.
4. Then have students share their feedback. The teacher should
MODEL good feedback, emphasizing the focus on the concept of a model.
5. During the presentation period, the teacher can keep a list of
hypotheses and questions that are generated.
6. When all skits are finished, refer to the list of questions
and ideas about where the food in the cotyledon comes from. If you have a Classroom Question Notebook, have each
group enter their question into the notebook.
WRAP UP:
"As we continue our investigations about how plants get
their food, we should remember our ideas and questions that we came up with today.
"Write in your science journals about whether you got any
new ideas or questions today. Did any of your ideas change? Remember that good thinking scientists always keep
an open mind and are willing to change their ideas when presented with good evidence and
arguments."