Monday, November 16, 2015

Biology: Senses, Behavior, Drugs

Almost caught up!   This is from two weeks ago. 

The first class was on the senses: the structure and function of the eye, the ear, the nose, etc.  This is a fun class because there are so many hands on experiments and demonstrations.  So fun that I forgot to take pictures.

For the eye, we looked at my selection of lenses, and I showed them how the image is flipped in a any curved surface.  I happen to have a curved mirror, but you can see it in a shiny spoon.  We literally see everything flipped, but our brains flip the image right side up for us.

I also showed them how our cones combine red, green, and blue light to make all the colors (LED finger lights in a dark room).  This is a source of amazement for anyone who was taught in kindergarten that yellow and blue make green...

I did the tongue and nose together, and I had set up a smell test  (extracts on cotton balls). 

We also did a fun taste test with skittles (jelly beans also work - any small fruity candy with several flavors). I gave each kid one of each skittle flavor, then I had them hold their noses and randomly eat a skittle without looking at the color.  Because your tongue can only taste sweet, sour, salty, biitter, or umami (savory), you really can't tell which one you ate until you unplug your nose!  The one exception was lime, because it was both sweet and sour. 

Plus I fed them all cookies, because, you know, teenager = hungry!

For the ear experiment, I focused on directional hearing.  I had them face away from me while I snapped in different locations.

They had no problems at all until I had them plug one ear!

This is why most of our sense organs are double, so that we can triangulate sounds, sights, and smells. Technically you only have one nose, but you have two nostrils for a reason!

Incidentally, this is also why snake's tongues are forked - they use them for locating things by smell.

For the touch test, I used two (sharpened) pencils to do a discrimination test.  You can do this on the hand, the arm, and the back of the neck, but I was running short on tiime, so I just did the back of the neck.

The idea is to lightly touch them with one or two pencil points and they tell you if they think it was one or two.  If the points are separated, they will always sense both, but if you move them closer together, only one signal will be detected.  The back of the neck is the least sensitive area for this test.

The other class was on behavior (stimulus and response) and drugs.  We talked about how different drugs work (stimulants and depressants), how to take drugs (read labels, determine dose, finish your prescription, check expiration dates, interactions, and side effects) and how and why to not take drugs (illegal drugs, others prescriptions).

For me, this was a really important class because it gives the kids a comprehensive framework to make the healthcare decisions that they will make as adults.  The classes on drugs that I had in school just dealt with "bad" drugs, alcohol, and smoking.  Certainly kids need to know about these things, but they also need to know how to responsibly use medication (and caffeine) in their daily lives.

We covered over the counter drugs, prescription drugs and illegal drugs.  We also talked a lot about dependence, addiction, and withdrawal, from caffeine to heroin.

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