Getting Food to The Cells (3)

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Students will be able to model the functioning and connections of the Digestive, Circulatory, and Respiratory systems.

Big Idea

Getting food and oxygen to the cells takes a lot of parts and coordination!

Teachers' Lounge

The purpose of this lesson is to have students simulate the connections between the circulatory, respiratory, and digestive systems by all an organ and passing food molecules and oxygen molecules around.  It is a chaotic day to say the least! A lot of time goes into organize the kids, giving them their parts and getting them in the right place.  However, I feel like the overall effect was powerful!

This was one of those days where we had half the regular amount of teaching time.  It made a perfect day to do this simulation, however there wasn't much time for processing.

Ready. Set. Engage

5 minutes

Learning Goal:  Demonstrate the connections between the Circulatory, Digestive, and Reproductive systems

Opening Question: Where does the food pass from the digestive to the circulatory system?  Where does the oxygen pass from the respiratory to the circulatory system?

Students come in the room, get ready (get their stuff), get set (get settled in their seats), and engage in writing the learning goal and answering the essential question on the board.

Follow the links to learn more about the beginning of class strategies and ROCK STAR scientist tickets.

Understand and Describe the Problem

10 minutes

The purpose of this section is for the students to understand and be ready to engage in this complex simulation.  I start be explaining that we are going to do a simulation of how the digestive, respiratory, and circulatory systems get food and oxygen to the cells.  In advance, I buy name tags at the super market that say, "Hi my name is..." and fill one out for all of these body parts.






Small Intestine



Small Vein (2)

Large Vein (2)

Left Ventricle



Air Sacs

Left Atrium

Right Atrium

Large Artery

Small Artery



This is a fairly fluid list.  If you have a small class simply make it Vein and Artery instead of having small veins and large veins.  Also, if you have more students you can have many cells and make sure that all the cells get food and oxygen.  On days when I have more time, I even time the simulation and have cells die if the body can't get food and oxygen to them.  

Obtain a Plan

10 minutes

This part of the lesson is the most difficult because you have to get the students in place and understanding their roles, while the students are excited and jumping around.  

Basically you are making a giant body of organs with the mouth and nose at the top and the cells at the bottom. Then students pass around sugar and oxygen molecules. Look at the resource below to see a possible way to set up the simulation. all models this will NOT be perfect.  There are small problems no matter how you set it up with that it is important to talk about later in the processing.  

The best place to start is with the heart.  Put four chairs in the middle of the room and then arrange the students as the right and left atriums and ventricles.  

Then start at the top of the room putting the digestive organs on one side and the respiratory organs on the other side.  

The circulatory connections are the hardest to get right.  Put Capillaries next to the villi and the air sacs.  

Going through the heart is the hardest part.  You can set it up so that the food is picked up and taken to the right side on the way to the lungs and then comes back through the left side to hit the body.  However this is INCREDIBLY difficult.  Another way to do it is just have a generic heart and have the food and oxygen both come through the heart from the veins and then leave through the arteries.  I would evaluate what your teaching is really about to make this decision.  We spend very little time on the parts, instead we focus on the connections and what is carried so I tend to do the latter set-up.

After the blood goes through the heart and into the large and small arteries, you will need another capillary before it gets to the cells.  

Carry out Plan

15 minutes

Once the kids are in place the hardest part is done.  I get some item to pass.  You can go all out and blow up little balloons for them to pass around or simply use little pieces of paper.  This year I used the paper their name tags were sticking to.  I always start with the digestive system and give them the piece of paper and have them pass it to the next person as they say their "name."  "Mouth." pass. "Esophagus." pass.  We go all the way around with just the food.  Then we do the Oxygen.  Then we do both at the same time.  Below is a video that caught the chaos and excitement of this well.  I have to say I think the video is rather hard to understand if you haven't just stood there and set up those kids, but it will give you an idea of what to expect.

The fun is in place. Now comes the important part -- expand and deepen learning.  We often talk about what part is working the hardest (They all say the heart) Then I ask them what happens when we exercise.  It is great to do some drill down here with exercise and have them come up with why your heart has to beat faster.  (You need more sugar and oxygen.)  If I have time I even simulate the pace picking up.  When I did this last one kid said, "Wow, no wonder we breath hard when we are running...that was hard!" 

Evaluate / Revise the Answer

12 minutes

It is important to always leave time for the reflection.  I didn't have much time today because it was a shortened class period so I simply asked kids what they learned from doing the simulation.

It is also a great time to point out that they have just made another model and that like any model there are things that are "right" about it and things that are "not so right" Taking the time to share and discuss these ideas can be a valuable learning experience.


3 minutes

This is such a high energy lesson that it is sometimes difficult to get kids to focus on closure! Generally I simply summarize what we did and preview that tomorrow we will be looking at how the nervous system, muscular system, and skeletal system connect to help you respond to events.  

Read more about effective ways to close your lesson, no matter how much time you have left!