What is a simple lab or demonstration I can do for the digestive system?I'm in need of a simple lab activity or demonstration I can do for the digestive system. I'm teaching a group of homeschool kids so my resources are extremely limited. The more simple the activity the better.
Thanks.
Posted by Sci~Teacher
I have my students do a series of stations for the digestive system.
For the mouth we put a cracker and a table spoon of water in a ziplock bag and pound on it to simulate chewing.
For the esophagus I we use a stocking (with the toe cut out) and a tennis ball to demonstrate peristalsis.
For the stomach we use a larger bag with green tinted water (and the material from the "mouth") and mush it to simulate the mechanical digetion of the stomach.
I haven't figured out a good small intestine model yet other than adding the "bile pigments" (yellow food coloring)
For the large intestine we put the stomach contents into another stocking (also with the toe cut out) and wrap it in a towel... we preform "peristalsis" on it and the towel absorbs the water...
fairly low tech and messy but it seems to get the point across.
Posted by Dan S
Set up a balloon a beaker and a piece of tubing.
1.Get some food and put it into the beaker and use a spoon to mash the food up; this is the teeth in the action. Use a knife to cut the mash into pieces, the teeth both grind and cut the food up. Then it is passed down the throat.
2.Pour water into the food mixture; this is the saliva used to help wash the food down.
3.Wash the food down the tube into the balloon and then add some hydrochloric acid, this is stomach acid, you will have to ask the science department for some HCL. If you can't get it then don't try to substitute any other acid because that can be dangerous.
4.Massage the balloon vigorously the stomach adds acid to the food and then its muscles mix and further dissolve and grind the food down.
5.Then pour the food out the balloon through the tubing into the beaker. Once the stomach has finished with the food it passes it to the next stage; absorption. It is passed through the small intestine where it is absorbed by the villa in the intestine. The nutrients are pulled out and absorbed in the small intestine where they can be sent off to the body to be used.
6.Use a pair of tongs and pull out some pieces of food and put them on a paper towel to represent the nutrients that are absorbed.
7.As the nutrients are absorbed the fiber and waste are left over and passed into the large intestine where they are processed some more to reduce them and stored for elimination.
8.Then the waste is passed out of the rectum as waste; excreted from the body. Extra liquids come out through the kidneys.
You can use clamps on the balloon to signify the sphincters or you can just use your fingers to hold it closed.
The human digestive system is 20 feet long it can take days to pass food through the system along the way the food is ground up, massaged, bathed in acid, broken down into pieces and the nutrients are absorbed by the body. Fiber serves as the debris that moves the food along, indigestible pieces like gum, most of celery etc. are simply passed along with the rest of the fiber by muscle contractions to be eliminated. Gum doesn't stay in your system for 7 years, most of it can't be digested so it is excreted.
For the food you should use some ground well cooked hamburger or a few pieces of cooked beef. You should add some water to the mix, maybe even a little soda pop (the fizz can represent your stomach acid), and some cooked potatoes. You want something that can be ground up fine enough to pass through your tubing and into your balloon.
A more complex model would have a sack with tubing leading into it and a second piece of tubing leading out. You can cut and grind up the food and then pass it into the first piece of tubing. If you use a clear sack then you can let people see you massage the food, then you can add your HCL or coke to represent your stomach acid to the mix. Then you can drain it out through the second piece of tubing, making it longer and use your fingers to represent muscle contractions pushing it along the intestine and eventually out of the body. Again you can use clamps to represent the organic valves that hold the food back for each stage and allow it to pass on when that stage is finished.
Orignal From: What is a simple lab or demonstration I can do for the digestive system?
Post a Comment