From: Monya Baker (monya_baker@yahoo.com)
Date: Sat Mar 01 2003 - 11:04:36 PST
Message-ID: <20030301190436.13602.qmail@web21107.mail.yahoo.com> Date: Sat, 1 Mar 2003 11:04:36 -0800 (PST) From: Monya Baker <monya_baker@yahoo.com> Subject: muscles, chicken feet, and yard sticks
This doesn't get the nervous impulse part, but the kids love it.
Get some chicken feet (Chinese and Mexican grocers often have this; they're cheap).Let the kids dissect of the skin until they can find a pearly tendon on one side that pulls the toes up and a pearly tendon on the other side that curls the toes down.
You can use scalpels, but razor blades work better. I don't know how old your students are or how big your classes, but I did this with 10th graders, and the loved it. My grading sheet was demo based: first they had to make the toes curl up, then down, moving a single toe was either required or extra credit depending on the time I had and the maturity of the class. You should collect or mark each foot after the demo so it doesn't get passed around. I've also had kids take off a toe and look at the joint. Afterwards or before, you can have students squeeze each other's relaxed wrists, making the fingers curl up. Very cool
Also, some of the feet will come with severed tendons, so you'll want some extra.
I had my kids wear gloves and soaked the feet in an antibacteria soluaion. You have to be careful, but the kids love it.
----If you want to demonstrate the sarcomere:
Get at least two yard sticks and tape sppons (or something) every few inches with a cap in the center. (depends on the size of your kids). This represents acitn, and the spoons are binding sites.
Hold the yardstick and have two kids stand on either side, Arm outstretched so that it just barely touches the yard stick. The students' arms represent myosin. Have the students move toward each other by grabbing the first "binding site" and pulling themselves in, then the next binding site, until they reach toward the center. Then ask the kids why a bicep bulges when an arm is curled. Then have them curl and flex their arms, and ask why the muscle to curl the arm up is bigger than the muscle that pulls the arm down.
You can put a cloth over the yardstick and explain tropomyosin if you like, which gives kids an idea of why it matters that the sarcoplasmic reticulum releases calcium.
End the activity by having students tell you how this is like and unlike the real thing to make sure you haven't taught any misconceptions.
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