Okay, if you have the book, you already know what Exercise 1 is all about - licking a battery.
Did it hurt? Nope... tingled... more of a surprise than anything...
After drying my tongue, I had to try a few times to feel anything. But even then, it wasn't much and may have been my imagination.
But the author's point is well taken - our bodies can conduct electricity, even from relatively weak sources like an alkaline battery.
Part of Exercise 1 is all about using your multimeter to take some measurements... unfortunately, my cheapy meter doesn't have the best of settings and can't go as high (with both ohms and voltage) as my autoranging one. I followed the instructions in the book (no less than 100k resistance) and took a measurement of my tongue... no luck. I had to crank up my meter to 2000k before I could get a reading. Maybe it's my meter, but the 200k setting didn't even provide results. (Maybe my tongue is super resistant!)
At 2000k setting, it finally started giving me results... they didn't match the target estimate in the book, but that's okay - I understand what the author is trying to get me to understand... by drying my tongue (or moving the probes further apart), I'm getting a higher resistance reading.
Next, I ran a wet towel down my arm (okay, I licked my left arm the first time - don't judge me. But on the next two tries I figured a towel would give more consistent readings on my right arm.)
Here's what I got:
at 4" apart, the probes had a reading of .7 mOhms
at 2" apart, they gave a reading of .5 mOhms
at .25" apart, the reading was around .4mOhms
On dry skin, I couldn't get any reading... zero. Even after putting the probes about 1/4" apart.
So, what should you take from the reading and exercises for Experiment 1?
* First off... read the manual for your multimeter. It may seem obvious, but it won't hurt for you to read it and know what each setting is for...
* Make sure you understand the chart (page 6) covering Ohms... and how to convert these values in your head using the k (kilo) and m (mega)...
* Know the terminology for items with high resistance and low resistance...
* Know the resistance of your tongue... it will be on a test someday...
* Write a 3 page report on the man who discovered resistance (to be graded by Mr. Platt)...
* And do the last experiment (bottom of page 8) so you'll understand why it's a very bad idea to swim in the ocean during a lightning storm.
Finally, to close out this post, please take note of my lab book in one of the photos. I highly suggest you find something to write down your notes, results, etc. A book like this will help you keep track of your experiments, any variations you may try (and their results), supplies you've run out of, new supplies for future experiments, and more.
See you tomorrow for Experiments 2 and 3.