What is Photosynthesis? Adapted from “C-E-L-L-O”

AK Standard: Science A3, B2, B3

Goal: Students will create model cell bodies to explore cellular structure and function.

Topic: Life Science

Methodology: Discussion

Possible Misconceptions or Naïve Ideas:

Plants pull “food” up through their roots.

Energy is linked to movement, so the absence of activity indicates the absence of energy.

Plants do not require energy.

Focus Question or Problem:

How do plants use energy?

Objective(s): Students will explore cellular structure and function. Students will understand that plants convert solar energy to cellulose.

Materials: “Photosynthesis Song” by Peter Weatherall, video playback device, cellular illustrations, packaged gelatin, hot and cold water, wooden spoons, measuring cups, cut-up fruits, plastic knives or safety scissors, waxed paper or plastic cups.

Activities: Ask students: Why do trees have leaves? What do leaves do for plants? Discuss student ideas, guiding discussion toward idea that plants use leaves to “make food,” using solar energy, and that this food helps them grow.

Ask if any students can explain how the plants use solar energy to create “food” to fuel growth. Discuss answers. Ask what students can think of that all plants can do; guide discussion toward answer of “photosynthesis;” play “Photosynthesis Song.”

Ask students what they think “cellulose” means. Discuss. Ask students to think about celery: what are its properties? Talk about the cellulose in celery and the importance of the cell wall in plant cells.

Discuss what students know about cellular structures, making note of any misconceptions raised. Discuss cellular illustrations and notable cellular structures and their functions within the cell.

Ask students to work in teams to make gelatin according to package instructions with adult supervision. Instruct students to use fruit pieces to construct a model cell using the gelatin to represent the cellular membrane and intercellular fluid. Allow students to reshape fruit pieces to better resemble their ideas about what cellular structures actually look like.

Accommodations for special learners:

Students will participate in whole-group discussion. Students will work cooperatively to complete exploration. Students will offer and defend ideas.

Attention to multicultural concerns:

No special accommodations will be provided.

Student Assessment

Students will participate in discussion portion of lesson. Students will work cooperatively to complete exploration. Students will offer and defend ideas.

Closure

Encourage students to discuss the process with their partners and to present their final "cells" to the class. Close with a disucssion of the process and a endosymbiosis party, wherein the cells are consumed by a larger "cell" (i.e., the student).

References:

Black, D.R., Grossman, M.C., Shapiro, I.I., and Ward, R.B. (2001). Exploring energy: Waterwheels, windmills, and sunlight teacher manual. Charlesbridge: Watertown, MA.

Goldfein, W. (2010). C-E-L-L-O. In Discovery education. Retrieved from http://school.discoveryeducation.com/lessonplans/programs/cello/

McREL. (2010). Pineapple JELL-O? In Mid-continent research for education and learning. Retrieved from http://www.mcrel.org/compendium/activityDetail.asp?activityID=159

ENDOSYMBIOSIS

DO NOT EAT ORGANELLES

Plant Cell Anatomy

The cell is the basic unit of life. Plant cells (unlike animal cells) are surrounded by a thick, rigid cell wall.

Evaluation Results

Author: Cindy Fitch

Date Evaluated: 05/02/2010 08:06:47 PM (ADT)

DRF template: Elementary Distance Credential/MAT

Program: Distance Elementary Graduate Certificate/MAT

Evaluation Method: Using Form

Evaluation Summary for Lesson Observation Forms: Lesson Observation Form ED 617-3

Final Score: Meets Requirement

Detailed Results (Form used: Lesson Observation Form)

Response is required

Teacher Candidate Name

Cindy Fitch

School

Creekside Elementary School

Students

Grade Level Number of Students

4th and 5th Grade 23

Lesson Observed

Lesson Topic Summary of Lesson

Science - Photosynthesis Students explore photosynthesis and cellularstructures in a guided exploration.

Content/Subject Area

Science

Lesson Observation

Please use this form to observe and give feedback to the teacher candidate. This is a formative assessment, and scoringis used only for feedback and to encourage improvement

Response Legend:1 = In progress; needs development 2 = Meets expectations for a beginning teacher

3 = Exceeds expectations for a beginning teacher; professional

Evaluation Results http://staffdev.taskstream.com/staff_dev/staff_dev/mentor/eval_report.asp...

1 of 3 4/28/2011 4:09 PM

1 2 3 N/A

The lesson plan was complete The teacher candidate was prepared The teacher candidate communicates effectively The lesson was developmentally appropriate Activities were differentiated for individuals and groups Content knowledge was accurate and current The teacher candidate demonstrated understanding of the context of the lesson in the curriculum The students were interested and engaged in active learning 1 2 3 N/A

The teacher candidate focused on student learning Assessment was appropriate for the learning objectives The lesson promoted higher order thinking, problem solving, and/or creativity Classroom management promoted student engagement The students met the learning objectives The teacher candidate reflected on student learning, lesson design and other issues

Lesson planning and preparation

Please describe observations of the lesson planning: knowledge of content, structure of lesson, materials, preparation,etc

Observations: Lesson Design Interpretation and suggestions

The lesson provided a good introduction and wholeclass discussion.

The lesson was interesting and captured thestudent's attention. They were quickly engaged andparticipating well.

Instruction; how the lesson went

Please take notes on what happened during the lesson: communication, questions and discussion, feedback, flexibilityand responsiveness, etc.

Observations: Instruction Interpretation and suggestions

Ms. Fitch introduced the lesson with questions andthen had the students respond. The students thenwatched a video that explained photosynthesis. Thestudents then were given instruction on how tocreate their own plant cell with jello and assorteditems to represent the plant organelles.

As this was an isolated lesson, many students didnot have the prior knowledge established to reallyparticipate in an informative discussion. There wasa sign created for one of the words used to describephotosynthesis, but a word list for the studentsposted on the board would have been helpful as theinsides of a plant cell was discussed. This couldhave easily been 3-4 lessons to ensureunderstanding.A crossword puzzle with definitions would havebeen useful. A copy of the word of the song andthen time to let the students sing it. Also, thestudents could have worked in groups to act out thesong, or drawn their own pictures to go with it.

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2 of 3 4/28/2011 4:09 PM

Classroom Management

Please observe the behavior and engagement of the students, noting in particular what the teacher candidate might notbe aware of.

Observations: Management Interpretation and Suggestions

Students were listening to begin with. As biggerwords they didn't know or understand were usedand introduced, they started to lose their focus.Students liked the video and song. Sudents wereextremely excited about the jello project. Theirexcitement was almost overwheming as theirbegan thier project. Some took their time andothers hurried through it to get to the eating part.

Check for student understanding throughout thelesson. Let the sudents guide how quickly things areintroduced. I know this lesson was on timecontraints - but when you are in your ownclassroom you will be able to adjust more.The main part of the lesson would be a greatculminating activity for a unit of plants.The preparation was amazing-well done, Ms Fitch.It was evident you had worked and organized formany hours to prepare this lesson.

Reflection

Notes on reflection after the lesson, for example:How did the lesson go?

Did the students meet the objective? How do you know?

Were there any unexpected events? How did you respond?

Comment on one student who did particularly well and one who did not meet your expectations. Why did this happen?What can you do to follow up with the student who did not do well?

Are there any changes you would make in this lesson if you could do it again? Why?

No answer specified

Evaluation Results http://staffdev.taskstream.com/staff_dev/staff_dev/mentor/eval_report.asp...

3 of 3 4/28/2011 4:09 PM

I taught this lesson on Friday, April 30, to a full cohort of 23 fourth- and fifth-graders. I do not think I am overstating things when I say that the lesson was an unreserved hit. I made a few, key changes to my lesson between planning and delivery, among which were the related decisions to make the JELL-O ahead of the lesson and to use candy instead of fruit, which might spoil if prepared much ahead of time, for the organelles.

I also changed my opener. Instead of immediately launching into discussion, I used a sign (attached) asking students to refrain from eating the organelles as an attention set. This led to a fruitful discussion about what organelles are and the definition of the term "endosymbiosis" and its application in theories surrounding the presence of mitochondira and chloroplasts in eukaryotic cells.

Following this discussion, I explained that we would be conducting an edible science exploration today and introduced the idea that everything living thing is made up of cells; this led to further discussion about the similarity of all multi-cellular life at the cellular level and the fact that DNA, which is sub-cellular, influences the differences in living things.

While the students watched the Photosynthesis Song and explanatory video (during which I reassured them that they would not be quizzed on terms), I distributed paper plate work surfaces and plastic utensils. After the video and song (which several of them were still humming), we talked about photosynthesis, chlorophyll, and how we can't make our own food the way plants can.

Then, I pulled a "cell body" out of my bag and held it up, explaining how the cell wall, cellular membrane, and cytoplasm work together to do the job of holding the cell together (leaving out explanations of things like microtubules altogether) and allow the cell to take in the things it needs to survive while removing those that mgiht harm it.

I then asked for a volunteer from each table to retrieve a set of cell bodies for their tables. I asked them to examine the cell bodies - reminding them of our no endosymbiosis rule - while I handed out important information to them (the cell drawing).

After they'd thoroughly examined their cell bodies, I asked for volunteers to tell me about the largest organelles on their diagrams. We talked about cell walls, membranes, and cytoplasm (including a complaint that there was no cellular membrane in their models) until someone asked about the Central Vacuole.

I held up a marshmallow and explained that this represented the Central Vacuole, which acts as something like a siphon for plant cells, since plants don't perspire the way we do, due in part to their semi-rigid, less-permeable cell walls, which we lack. The students clamored for their vacuoles and I reminded them of the no endosymbiosis rule.

I then invited them to make room in their cytoplasm for the organelles and began handing out organelle packages to the students. Most scooped out almost all of the cytoplasm, then began cramming as organelles into the cellular wall containers as quickly as they could. A few chose to

layer cytoplasm and organelles, then expressed concern over what to do with the remaining cytoplasm.

I asked them to use their diagrams to complete their cell models, cautioning them that they would be asked to refrain from endosymbiosis until I agreed that they had compeleted their cells. We stopped activity frequently to discuss various organelles and their functions as students encountered them.

My second favorite part of the exploration (after the students' many, many questions about what each organelle does in a cell) happened when another teacher dropped in on my host teacher unexpectedly. He saw that the students were making cellular models and decided to quiz them.

They were able to talk to him about mitochondria ("the cell's furnace!"), the endoplasmic reticulum ("it's like a highway - for small stuff"), and the Golgi complex ("a tiny packaging store") as they worked. This use of terminology continued, both when explaining things to their teacher and when asking for more candy ("Do you have any more organelles? I really liked the nucleus.")

I look forward to teaching this lesson again, in the future. I think that, as a capstone of a unit on cells, it would be even more powerful. In that instance, I think I would insist on more precise placement of the organelles (rather than generally right) and would allow the students to create their cells using liquid JELL-O instead of scooping out already-gelled gelatin to make more room.

I believe this activity would really shine as part of a cellular museum project, in which students choose among several cell models to create - and discuss the ways in which their models are similar to and different from the real McCoy.