Students still struggle to understand things they cannot see. We show them images and describe the functions of the cell organelle but it is still hard to make the connection to active, very busy system with hundreds, even thousands of organelle. To help students make sense of what actually happens in a cell we can use analogies to help them compare a system they are very familiar with to one that is still very abstract.
Investigation Summary & Preparation
In order to develop and use a model to describe the function of organelle within a cell, students will develop analogies to compare organelle as part of a cellular system to parts of a system they are already familiar with. (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.)
Students will dig deeper into understanding cell organelle by making comparisons of the cell as a system and relating the function of each organelle to a system they already understand. (SP1 - Asking questions and defining problems)
The analogies become models showing student depth of understanding of cells as systems (SP 2 - Developing and using models)
In order to develop the analogies, student must have a good understanding of the form and function of each of the cells organelle. (SP4 - Analyzing and interpreting data)
Writing analogies requires students to communicate their understanding or organelle form and function in a concise parallel comparison. (SP8 - Obtaining, evaluating and communicating information) (RST.6-8.2 - Determine the central ideas or conclusions of a text; provide an accurate summary of the text distinct from prior knowledge or opinions.)
This lesson was created as the result of student generated Need-to-Know lists complete during the Cell Organelle Children's Book Project.
Students in Action
What is an analogy? Analogies are a useful way to compare topics that are difficult to understand to topics that we understand.
When we are writing analogies it is important to know our audience. Remember that the system you use to write analogies to understand cell organelle has to be a system that is familiar to our audience. In this case, our audience to cell analogies are children in grades 3 - 5. (This lesson is a Need-To-Know from the Cell Organelle Children's Book Project.)
To help you better understand analogies we will complete Cell City Analogy - Let's Practice Writing Analogies together.
Every element in the city of Greensburg can be compared to a cell organelle. Read through the two paragraphs on your own. Then Turn/Talk/Record with your elbow partner. When you are talking, reread the sentence with the underlined word. Use the notes in your journal to compare the function of the element in the city to the function of each organelle. (Students have researched information about the organelle using the website Cells Alive and made notes in their Science Journal.)
On the line next to organelle listed, write the city element that is the best match when comparing functions. (Student journal entries include notes from research they have completed about the major cell organelle that must be included in the Cell Organelle Children's Book Project.)
In a faraway city called Greensburg, the main export and production product is the steel widget. Everyone in the town has something to do with steel widget making and the entire town is designed to build and export widgets. The town hall has the instructions for widget making, widgets come in all shapes and sizes and any citizen of Grant can get the instructions and begin making their own widgets. Widgets are generally produced in small shops around the city, these small shops can be built by the carpenters union (whose headquarters are in town hall).
After the widget is constructed, they are placed on special carts which can deliver the widget anywhere in the city. In order for a widget to be exported, the carts take the widget to the postal office, where the widgets are packaged and labeled for export. Sometimes widgets don’t turn out right, and the “rejects” are sent to the scrap yard where they are broken down for parts or destroyed altogether. The town powers the widget shops and carts from a hydraulic dam that is in the city. The entire city is enclosed by a large wooden fence, only the postal trucks (and citizens with proper passports) are allowed outside the city.
As I circulate around the room, I check student responses and talk to student groups about any matches that appear to be inaccurate.
I encourage students to complete the analogies on their own. After all student groups have finished the comparisons, we tackle the analogies as a large group.
Mitochondria hydraulic dam
The mitochondria provides energy for the cell.
The hydraulic dam provides energy for the city.
Ribosomes small shops
The ribosomes produce protein for the cell.
The small shops produce widgets for the city.
Nucleus town hall
The nucleus has instructions for making new cells.
The town hall has instructions for making new widgets.
Endoplasmic Reticulum town hall
The endoplasmic reticulum delivers proteins to other parts of the cell.
The town hall delivers widgets to other parts of the city.
Golgi Apparatus post office
The Golgi apparatus packages and delivers proteins.
The post office packages and delivers widgets.
Cell Membrane fence
The cell membrane protects the cell and controls what goes in and out of the cell.
The fence protects the city and controls what goes in and out of the city.
Lysosomes scrap yard
The lysosomes recycle old cell parts.
The lysosomes recycle old widgets.
I remind students that it is important that the sentences use parallel language. The big idea behind using analogies in this context, is that we are showing a comparison between something unfamiliar, the cell organelle, to something very familiar, the city. We do not want to leave doubt in our reader's mind about the function of the organelle.
In this short video, I explain why writing analogies is an effective strategy for developing conceptual understanding models.
Connecting the Learning
In conclusion I share Cell Analogies: The Hunger Games, which compares the Hunger Games to cell organelles.
My students are inspired by the video. Most of the students have either read Hunger Games or have seen the movie so they immediately understand the analogy comparisons. Since students are writing a book for students in grades 3 - 5, we talk about how using these analogies are inappropriate for their project. We would not recommend the 8 - 10 year old students read Hunger Games.
I further caution students that just because a cell analogy is found on the internet does not mean it is correct. I share a story from last school year. I was conferencing with a student about his cell analogy project. I explained that several of his comparisons did not make sense as they did not accurately compare the function of the two systems. The student became frustrated and blurted out that it had to be correct, he copied it from the internet. Lesson learned.