Are We Going Bananas?

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Students understand the trait of what it means to be cold blooded.

Big Idea

Using bananas, students measure temperature after the banana has been exposed to heat and cold in order to understand what it means to be "cold blooded."


10 minutes

I opened the lesson today with asking if students thought a banana was alive? What is a banana? 

What specialized part of the plant is a banana? What do you think? I opened the lesson today with a movie about bananas that helps us understand what specialized part of the plant the banana is and how they grow. This video helps students understand the banana as a fruit, even though we will use it as a model for an animal trait. After the video, I transitioned them into the investigation by switching my questioning about models. I then explained how we would be using bananas as a model for discovering how a cold blooded animal's body temperature works.


30 minutes

Materials: Bananas peeled and cut in half, bananas with peeling on and cut in half,( enough so that each group has 3 halves to work with),  Celsius Thermometer, Graph. A way of warming ( without cooking) the banana so there is one warm banana half for each group, enough ice to make the banana cold ( put the bananas in the refrigerator with the peel on ( enough so that there is one cold banana for each group). A container that holds each set of banana halves labeled : Room Temperature, Warm & Cold. There should be a both a peeled and unpeeled banana in each container. 

Prior to the lesson, each desk team was given two thermometers, a copy of the data sheet, a graph and a KLEWS chart. I also put a pie tin on each desk so they had a place to put their bananas as they worked without making too much of a mess.

Setting Up Math Skills: I taught my students how to read the Celsius thermometer by using an interactive thermometer. I like this site because it shows relative temperatures so students can understand relative temperatures as they learn to read the thermometer. We played with the site for a few minutes and then I modeled how to insert the thermometer into the banana properly to get a reading. I explained how one side reads in Fahrenheit and the other in Celsius, showing them exactly which side to look and record temperatures from.

 I explained that all temperature recordings needed to be done first on the data sheet. Then, I expected that they would collaborate and create their personal bar graphs by figuring out how to scale the temperature side of the graph. I explained that after they gathered their information, created their graph, they needed to draw a conclusion based on their evidence as a group. They needed to discuss their findings, what the graph says to them and then write.

Next, I wrote the Driving Question on the white board: What does it mean to be a cold blooded animal? How does this trait affect how this animal adapts and survives?

I told them that our bananas today were serving as a model of a cold blooded animal. I held up the banana with the peel on it and told them that some were peeled and some had the peeling on it. I asked them to measure the room temperature peeled banana first, and then graph the temperature on the prepared bar graph. Then I told them to make a prediction of what temperature the banana with the peel would be and graph the prediction. ( Student misconception: the peel will keep the banana warm.) Then, they needed to measure the banana with the peel and graph the exact temperature. They were to repeat it for the warm and cold bananas.

I explained specifically how each table group would rotate their types of bananas. I assigned table teams according to cold, hot and room temperature bananas, so there wouldn't be too much traffic or confusion on who has which bananas. 

I explained again that we would be measuring the temperature of each banana half and graphing it after all the data was collected so they could set the scale on their graphs.

Students began to work on their project  desk groups. I roved the classroom, monitoring their accuracy and then was there to coach them as they began their graphing. KLEWS charts started to be filled in with their "wonders" as I really encouraged them to write questions down. Often they asked me questions that I knew would be revealed as the investigation proceeded and data was interpreted. This supports the inquiry process fully and makes it much more meaningful, rather than me giving in to explaining every question.







Sharing Our Data

15 minutes

As we shared our data, I created line plots on a blank page of a Notebook file.  One line plot was labeled bananas with peeling and one without. That way we could determine if having peeling would make a difference. This line plot is another way to show information as a whole class. Students could see how quickly we are able to gather and present data of the whole class. After determining the ranges of numbers from each group for temperatures and color coding how each type of banana would be charted, ( red for banana in hot water), I explained exactly how we would put the line plot together.  On student from each table group  marked where their x should be placed on the line plot, using the correct color coding. It took awhile for them to realize that the data showed us a possibility of a conclusion. I asked a lot of questions like:

What do you notice about the temperature ranges of the bananas that were in the ice? 

What do you notice about the banana temperature ranges with peels? What about without?

And then, I used the dialogue to point them in the right directions. These questions are so important to stimulate conversation about the small range difference which helps them understand that the small difference is not significant enough to reason that if we would put a jacket on a cold blooded animal, it would keep warm. This is a very hard realization for some of my students. They still think if we put a blanket on Ringo (our classroom tortoise) when it is cold out, that it will keep him warm. That is why it's important to also discuss insulators and how that works. It makes them aware of how math and science are connected and how we use the data we collect to achieve understanding.

When all was done, we summarized what we had learned about the temperature differences, the ranges of temperatures and students were able to conclude that our banana models were our proof of how a cold blooded animal's body works.