In this lesson, students create a model of a cell using candy as they connect the structure of the candy to the structure and function of cell organelles.
This lesson is specifically designed to address the following NGSS and Common Core Standards:
MS-LS1-2 Develop and use a model to describe the function of a cell as a whole and ways parts of cells contribute to the function.
CCSS.ELA-LITERACY.RST.6-8.7 Integrate quantitative or technical information expressed in words in a text with a version of that information expressed visually (e.g., in a flowchart, diagram, model, graph, or table).
Science and Engineering Practices:
The NGSS explains that students should be able to develop a model to describe unobservable mechanisms (SP2). As students in this lesson use candies to model the organelles in a cell!
As students create their model cells, students in this lab begin to tie together the idea of how the structure of the organelles in a cell relates to its job for the cell (Structure and Function).
Begin class by asking, "What are you going to learn today?". Students should respond by referring to the Essential Question, "How do cells contribute to the function of living organisms?". This EQ can be referenced both on my front board as well as on their Cells Unit Plan.
Have students get out their Cells Unit Plan. Explain that their focus of this particular lesson is Skill 2: I can provide evidence that cells are made up of organelles that have specific jobs. As the students have had multiple lessons focusing on this learning target, have students reread the skill and self-assess where they stand in their level of mastery in this skill. Students rank themselves on a scale of 1 to 4 (4 being mastery). At this point in the unit, students should be reaching mastery. Encourage them to seek help or make a plan to reach mastery if they do not feel as if they are there for this learning target.
As the unit moves forward, I have the students continually self-assess on each skill. In my class, this will be the students second self-assessment, so they change their scores if they feel that their learning has improved. Check out the student's unit plan below to see how students update their mastery level with each lesson.
At this point in the unit, the students are aware that cells are made of organelles and that they each perform functions for the cell. In addition, they have had some experience with organelles and their functions specifically. I have included a resource called "Cell Organelles Notes Page" that serves as the students reference as they create their models.
1. Explain to the students that their goal is to create a model of an animal cell using candy including jello, nerds, gobstopper, hot tamales, two small (but different) fruit roll-up sections, and chocolate covered raisins. I emphasize that each candy must represent a different organelle. I avoid telling the students which organelles they need to use, this limits the creativity allowed to the students. I encourage them to use their text as a reference to aid them with their decisions.
**Depending on how much you want to purchase and spend, each group can make a model with one of each of the candies, a "pinch" of nerds, and about 4 oz of prepared jello. The jello is going to get messy, it won't stay together and that is ok! One of my students says, "It actually is better that the jello is forming a 'weird' shape, that looks more like an animal cell. If it staying in a rectangular structure, it might appear more like a plant cell." :)
**Check for food allergies first!
2. Before they can eat their cell, they must explain the reasoning for the choices they made in their model to me. When they explain their models, for each piece of candy they must explain how the structure of the candy and the organelle is similar and how the structure relates to the function. For example, students cannot just say, "The chocolate covered raisin is the vacuole" or, "The chocolate covered raisin is the vacuole because the chocolate surrounds the raisin". They must say something like, "The chocolate covered raisin is the vacuole because the chocolate surrounds the raisin. This is similar to the vacuole that stores material for the cell."
Notice that there are differences in all of the models based on the students interpretation of the candy. For example, some use a fruit roll-up as the golgi apparatus (top left), some as the cell membrane (top right), some the endoplasmic reticulum (bottom). Some use the nerds as the ribosomes (top left), molecules trying to pass through the fruit roll-up (top right), or the vesicles (bottom).
3. After eating their cell and cleaning up, I write the following 3 questions on the board and the students answer them on a blank sheet of printer paper.
1. Draw a diagram of your model cell.
2. Draw a Venn Diagram and compare and contrast our model cell to a real cell.
3. What would have to be changed if we were going to make our model a plant cell?
**The next section, A Look at Student Work, is key to bringing meaning to these questions and the expectations that I have for the kids in completing them. Especially for the Venn diagram, check out the tips and student work that I show. It will help increase the rigor of this lab.
There will be variation in student models, which I think is awesome. For example, there are those that will choose the gobstopper to be the vacuole because the layers of the gobstopper represent what the vacuole is storing; others will say that the gobstopper is the nucleus because it is large, round and that the layers can be an analogy to the instructions for the cell.
As long as students can connect their choices to the structure and function of the organelle, it works! On their lab sheet, I did not have them write out their reasoning as I had them verbally explain their models to me. If you don't have time to have your students verbally explain their model, you could ask students to write the reasoning for their choices as the caption to their diagram.
In the overlap, or similarities section, of the Venn Diagram, students often note that the model and a real cell are made up of some of the same organelles, that the structures are related to the functions of the organelles, and that they are both made up of molecules.
The Venn diagram for me is a great place to see if students really have a conceptual understanding of what a cell looks like. I purposely do this lab towards the end of my cells unit. This way the students can return to the idea of organelles and make a model that reflects a deeper level of thinking. For example, the student above on the left notes that a real cell would be made of water, carbohydrates, lipids, nucleic acids, and protein. Furthermore, the student on the right is able to not only able to identify that we didn't model all of the possible organelles, but that there are more of "each". This student is referencing the idea that while they may have only used one or two hot tamales for the mitochondria, there are cells that could have thousands of mitochondria.
However, when looking at the two student Venn diagrams that I included here, I feel as if they both have work to do in terms of comparing and contrasting a real cell to our model. This Venn diagram for me is a great moment for formative assessment. Based on their observations recorded in their Venn diagram, I can pull groups of learners in a future lesson to figure out if they are really having misconceptions about what a cell looks like, or if they simply need help in looking at patterns in models to identify similarities and differences. Both of these are important and warrant a conference!
When conferencing with these groups, I have the students come to a poster I have in my classroom of a cell. I have the students also bring with them their unit plan with the skills listed on them. At the poster, I also have a picture of an actual candy model that a group created during this lesson so that they can have a visual of what the model actually looked like.
I have found that one skill that middle school students need practice with is how to connect themselves to the big picture in every lesson. While beginning the class with, "What are you going to learn today?" and having them self-assess on the skills helps, they still need practice. Using the unit plan as a tool to identify the similarities and differences in a cell really helps here. Check out the video below to see how when students connect back to their Essential Question and skills, they can think more deeply than they had on their original Venn diagrams.
The students note that a plant cell would require the addition of chloroplasts, a cell wall, and a larger central vacuole.
Ask each group to find two different groups and share the decisions that they made for their models. Their goal as they share is to identify both patterns in the models and those organelles that may have varied between groups. As they will already have eaten their cells, they can use the diagram they drew for the lab as their reference of their models.