Thursday, September 13, 2012

The Digestive System

We have just started to work on the digestive system. After the abstract concepts of the respiratory and circulatory system (NOT that digestion is any less abstract, but at least I have found some great ideas on Pinterest that I could do with my kids), I was truly looking forward to the digestive system. This is what we have been up to:
Lesson 1:
To get an overview of the digestive system we began by watching a short video on BrainPOP. (You do need a subscription to this site) While my students watched the video they took notes in their science notebook on their own of what they felt was important, as well as filled in a digestive system diagram as best as they could. We will go over it together later on and add important/missing information and details.

There is another great video on youtube, called Log Ride, you can show your students. It has a very funny ending.

Lesson 2:  We began by reading the section of the mouth in our Science Resource book. Students observed each others mouth and drew what they saw in their notebooks. They were amazed at what was in their mouths and were really excited to share their observations.

We then took it a step further and did a gross, but fun project. Students were asked to take a cracker and draw what it looked like before it gets placed in their mouths in their science notebook. They were then asked to place it in their mouths, chew it 2 times, stop chewing, open their mouths and allow their partner to observe the contents of their mouths. The observing partner had to draw what they saw. As you can imagine, this created a lot of onomatopoeia from my students as well as other phrases. We repeated the steps above 3 times. By then the cracker had pretty much dissolved in their mouths and they were allowed to swallow. We debriefed on what they saw:
"food breaks down into smaller pieces"
"food gets mushy"
"food clumps together", etc.

We then discussed what part of what occurred was the mechanical digestion and what part was the chemical digestion. We then renamed chewed food into bolus. (they love academic words)

Lesson 3: This lesson also started out with reading about the esophagus from our Science Resource book. We discussed where the food goes after it leaves our mouth. To help my students the process, I took some pantyhose and cut them in half. Each team got 1 leg of the pantyhose (the esophagus) with one large plastic egg (the bolus). They had to move the bolus along the esophagus without touching the egg, keeping the "esophagus" vertical, and without shaking it in any way.
They were able to observe by doing, that the walls of the esophagus propel food to the stomach not by gravity, but by rhythmic waves of muscular contractions called peristalsis.
We also discussed other times we become aware of our esophagus, when we sometimes feel the esophagus when we swallow something too large, try to eat too quickly, or drink very hot or cold liquids.

We will be working on the stomach, small intestine, and others as the days go by. Will post pictures later.

My students are having a blast learning, I am having a blast teaching, and hopefully it will all come together for our district assessment.

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