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     Activity 5: "Plants And People: Is Their Food The Same?"


                           ACTIVITY 5 - STUDENT'S PAGE

(It may be helpful to view the student page alongside this teacher page.)


Purposes:

In the last lesson, most students probably thought about the definition of food by considering themselves -- food for humans. Now we shift to thinking about the central issue of this unit -- food for plants.

In this lesson the focus is on establishing a shared inquiry question for the unit: What is food for plants?
How do plants get their food?

Through this activity students will generate a good list of hypotheses about food for plants. They will see that as a class, we can generate many different ideas, or hypotheses, about food for plants. This variety of viewpoints should help students see that there are many different ideas about this question.

Teacher's Role

The teacher's role here is to help students appreciate this diversity of viewpoints, wonder about which ideas are really "true," and think about ways we could begin to investigate to find evidence to support or challenge each of these hypotheses.

Materials:

This picture of a plant going to the grocery store (could be made into an overhead transparency).

A Possible Teacher Narrative:

FRAME

Read this page together or look this picture together.

Discuss: "In what ways are plants different from people? Does the cartoon accurately portray how plants get their food? Is this a good model? Why or why not?

Common Student Responses
Suggested Teacher Interpretations and Responses

Plants can't walk!
Plants do not get their food from the
grocery store like we do.
Plants don't have to move around to get
their food. Their food comes to
them--from rain, from the soil, from the
sun.
Keep encouraging students to think about this picture as a MODEL of
how plants get their food. How do we know this model is not accurate?
What is your evidence that plants don't walk? that plants don't go to
the grocery store?


Establish the problem and Elicit Students' Ideas

ACTIVITY--Writing about our Ideas

A Possible Teacher Narrative:

"In this unit, we will be trying to come up with a better model of how plants get their food than the picture we just looked at. We will start by finding out as much as we can about what we as a class already know about food for plants. What are our ideas, or hypotheses, about how plants get their food?"

"A hypothesis is an idea about an answer to a question. It is an idea that can be tested through
experiments. We are going to do some tests to find out the different hypotheses that we come up with."

"Answer the 3 questions on this page, trying to get down as many of your ideas as possible. Remember, the best answers will tell honestly what you think (optional: and why you think that). There is no one right answer. We want to find out how many different ideas we have as a class of scientists."

Allow students time to write. Encourage students to write WHAT THEY THINK. Do not try to correct them, edit them, or guide them to different answers as they write. Tell them to spell words as best they can.

Common Student Responses and Suggested Teacher Actions


Food for plants is water that they take in
through the roots.
Plants get food by taking it in from the
soil.
Food for plants is what they need to
grow.
Sun, water, air, soil, and fertilizer are
food for plants.
People give plant food to plants -- it's
little sticks that you buy at the store.
Plants make their food in the soil.

Interpretation

Both of the questions on this page are exploratory questions designed
to elicit students' ways of thinking about food for plants and to
establish a problem that the group will investigate throughout this unit.

Water is one of the most common responses. Many students list
multiple sources of food for plants. Some students tend to think about
anything plants need as food for the plant. Others think that whatever
plants take into their bodies ("eat") is food for plants. Still others
identify only fertilizers or minerals as food for plants.

Scientific Conception

While many students consider raw materials in the plants' environment
as the plants' food, the scientific conception is that plants get their
food by making it themselves by using energy from the sun to change
water and carbon-dioxide into energy-containing food (glucose). This
process, photosynthesis, takes place inside special cells in the leaves.
This is the goal concept of the unit.

The unit is designed to support students in changing their initial
hypotheses to this scientific conception. They will be asked to come
back to what they have written on these pages and revise their answers
based on what they have learned from the unit.


ACTIVITY--Getting Ready to Talk!

Read or talk about ways of having good scientific discussions, using this page as a guide.

Students often mention Back to the Future as a movie portraying a stereotypical scientist -- a mad, crazy white man who works alone in his laboratory, isolated from the rest of society.

The movie Lorenzo's Oil is an example of a movie that has scenes where scientists are working together in conference and meeting settings to solve the dilemmas or a rare and fatal disease, ALH. Can you think of other examples? What are some more recent movies that these students might have seen?

IMPORTANT NOTES ABOUT SCIENCE TALKS

The more you can have students facing each other (instead of facing you) the better! Can you arrange desks or chairs in a u-shape, or circular shape?

Take the time to talk explicitly about the kinds of talk that scientists do and how we can use those modes of thinking and talking in our inquiry.

You might even want to create with the students a set of RULES OR GUIDELINES FOR SCIENCE TALKS.
These rules or guidelines could be posted and used regularly throughout this and other units. Examples of rules might include:

Show respect for other people's ideas by:

Listening carefully to their ideas.

Not making fun or laughing at anyone's ideas.

Agreeing or disagreeing with their ideas by giving reasons.

Not telling people they are wrong.

Asking someone more about their idea.

Adding on to someone else's idea.

Don't dominate the discussion. Let lots of people have a turn to talk.

*You might want to create a class-sized poster of this table (A Guide to Good Science Talks) to post for regular class use.

*Encourage students to respond to each other's ideas rather than to speak to the teacher. You might try having students call on each other as they get more comfortable and skilled at these kinds of discussions.

*Assign 1-2 students as OBSERVERS. Have the observers take notes about particular aspects of the
science talk. For example, you might start by having one student keep track of how many different people participated, and another student keep track of examples of people adding on to someone else's idea or providing evidence to support or challenge an hypothesis. Have OBSERVERS report back to the class at the end of the discussion. How are we doing in becoming good at talking science?

A QUESTION NOTEBOOK

You might introduce at this point a class Question Notebook. The purpose of this notebook is to keep track of the many questions that students will generate throughout the unit. When a student has a good question (which may come up during discussions or during group activities or at other more private moments during the day), the student writes the question, the date, and his/her name in the book. The teacher encourages the students to record questions here, and the questions are celebrated as evidence of good scientific thinking. The teacher can return to questions students raised that they may be able to answer themselves at a later point in the unit using knowledge gained through their inquiry. You can use a composition type notebook or a 3-ring binder or a spiral notebook. Simply put a large, prominent question mark on the cover and keep the book in a location that is easily accessible to students!

Establish the problem And Elicit students' ideas

ACTIVITY--Let's Talk!

Materials: Some method for recording and keeping for public display (poster, overhead, chalkboard).

A Possible Teacher Narrative:

"Let's see how many ideas, or hypotheses, we have about how plants get their food. I will keep a list of our ideas on the board/overhead/poster. I want you to listen carefully to other scientists' ideas. Do you have evidence to support or challenge their ideas? Do you agree or disagree? Why? Are you clear about the other person is saying? Can you ask a question to get clearer about what someone else means? "

"Let's try to have a good scientific discussion. What would we like our OBSERVERS to keep track of for us?
What do we want to know about how we are doing in having a scientific discussion?"

Go over any rules for science talks that you and/or your students have created.

Keep in mind the ideas on page ?? about the kinds of ideas your students might generate.

Write down for public display students' ideas as they are offered. Be sure to write down the name of the student who offered the idea!

Accept all student suggestions but be sure to emphasize that they are all hypotheses at this point -- that we will need to test them to find more evidence to support or challenge them. Tell them that the unit should help them change their ideas.

Encourage students to elaborate about their hypotheses by giving any evidence they might have to support their hypotheses. This should elicit stories about students' experiences with plants.

Being Sensitive to Student Diversity

About Plants--- Students will have a wide range of experiences with plants, both firsthand and in their families and communities. Take the time to hear about a variety of such experiences, even if it feels like a lot of time is being spent on personal experience stories. These stories are IMPORTANT in enabling many students to find connections and meaning in science and to engage them in considering the central question of this unit. Be especially attentive to stories that reflect cultural values and experiences. For example, students of Native American descent might have special ways of honoring and respecting plants, and students of Mexican American heritage may have interesting stories about farming or migrant farming in their family history. Some students might encounter plants primarily as weeds or decorations on city streets.

About Ways of Talking and Working in a Group -- Watch your students' discussion patterns. Do you notice stereotypical gender differences in who participates and how? Do the boys tend to dominate the discussion, interrupt more, get called on more often? Do the girls tend to speak more softly, more tentatively, and to be less hesitant to share their ideas? If so, you may need to talk to students about these observations and about the reasons that you want everyone participating -- to promote their own best learning (not to show off for the teacher and classmates). Notice who the quiet students are in your discussions. Consider getting to know these students in ways that will help you understand their
quietness. Are these students showing respect for elders by such quietness? Are they hiding their fear of making a mistake? Again, you can help them learn to show respect for others in a new way -- by contributing to the conversation rather than always listening respectfully.