Heather Booher: Science Educator

After interning in my life science class for nine weeks, I had seen the students cover characteristics and needs of living things, the scientific method, the metric system, leaf collections, and the periodic table. For my last two weeks in the classroom, I really wanted to do something fun with the kids, and my cooperating teacher agreed that they needed a break from the seriousness that the Periodic Table lesson had been. The cell lesson started with the basics; the differences between plant and animal cells and the functions of the major organelles in both cell types. My teacher wanted the children to gain a good base on the basics of cells, because he feels it is the most important unit they will have all year, and it lasts until the students have Winter Break. So, as a fun way to introduce basic cell structures and organelle functions, I decided to have the kids make edible cell models. I allowed them to work in small groups for this project, which they could pick themselves.

I investigated the prior knowledge of students by interviewing four random students from Advisory (two boys and two girls). The night before I interviewed them, the students’ homework had been to read 12 pages in the textbook which introduced cells for the first time and contained many great diagrams. None of the four students I talked with had done the reading however, so their answers to my questions were mainly guesses. The first question I asked each student was, “Are there any differences between plant and animal cells?” All four agreed that there were differences between the two cell types, so I asked them to elaborate:

Christian: Plants have cells that work with the sun; animals don’t have those.

Lindsay: Yeah, they’re called chloroplasts.

Mike: One of them is a square, and one is a circle.

ALL: Yeah, they have different shapes.

Jesse: I don’t know, I didn’t read the homework and I don’t know anything about cells.

I then asked which type of cell the students believed was “square” and which was the “circle.” They all agreed that plant cells were squares and animal cells were circles because they remembered seeing pictures that depicted them that way. I asked if they knew why plant cells were typically drawn as rigid squares, while animal cells were more flexible circles, but they had no idea. My next question to them was “What are organelles inside of the cell?” but none of the students could name any. I asked if they had ever heard the term ‘organelle’ before, and they responded:

Lindsay: Yeah, but I don’t know what it is.

Mike, Jesse and Christian: I’ve never heard it before.

Finally, I asked all four students if they could try and sketch an animal or a plant cell for me, and label as many parts as possible. Christian refused to draw anything because he said he didn’t know what they looked like. I reminded all of them that they had looked at plant cells under microscopes about a month prior to this and they responded that it was too long ago for them to remember. Lindsay and Jesse each drew an animal cell that was nothing more than a circle, and a plant cell that was a square. Mike drew a plant cell and labeled the cytoplasm and cell wall correctly, but he had random chromosomes floating around the entire cell. He didn’t know that what he had drawn resembled chromosomes when I asked him; he said they just “looked familiar, like something from the book.”

 

After conducting these interviews, I spent a planning period discussing with my cooperating teacher the best way to go about my cell lesson plan. He had a lot of really helpful advice, and together we worked out a game plan that would take approximately three days. Students worked cooperatively to design an edible cell model, and complete a corresponding worksheet. Following the lesson, I re-interviewed the same four students to see if their basic knowledge of cells had improved. This time when I asked what the differences between plant and animal cells, the responses were:

Lindsay: Well, besides the chloroplasts, plant cells have a cell wall and animal cells don’t.

Christian: Yeah, plant cells have different structures, and they make chlorophyll. Animal cells don’t have to make chlorophyll.

I asked, “What are some of the organelles found in the cell?”

Mike: Vacuoles, ribosomes, and the nucleolus.

Jesse: The one that makes all the energy for the cell…I forget what its called.

Christian: Mitochondria. And there’s also the cell wall, cell membrane, nucleus, cytoplasm and chloroplasts.

I asked the students why they thought that plant cells would need a cell wall, while animal cells only needed a cell membrane, but they had a very difficult time with this question. I had also asked them this question on the worksheet that they had to complete with their groups, and I noticed that a large number of students had difficulty with this question. It was the only one on the worksheet that couldn’t be found directly in the textbook, it required a little extra thought.

This time, when I asked the students to draw a picture of a cell, the result was this:

Overall, I think this activity was successful because it introduced the students to a difficult and important topic, and they had fun doing it. As a social activity, it was especially successful. The students all worked well together and it was a different way to incorporate group work, which is not an opportunity they get very often.