Some quick notes and resources for our fifth day's topic, which was Microbiology and The Nervous System.
Remember that all of my notes for this main lesson block can be found in much more detail on my website.
We began today by discussing our visit to the Microbiology presentation on Friday, and reflecting on our next steps in the experiment protocol. We sterilized our equipment (six ceramic mini loaf pans and a 2 cup Pyrex measuring cup) by wrapping it in aluminum foil and placing it in a 375 degree oven for 45 minutes, then leaving it in the oven until cool. Tomorrow we will move on to setting up the actual Bacteria experiment.
Dr. Scott Hamilton-Brehm also suggested that we use only boiled distilled water for our experiment and not tap water. We took a few minutes and looked at the Water Quality Reports for the city of Carbondale, as well as for the water system at my mother's house, and compared them. We also looked at the Drinking Water Alert which our city sent out just last week, about the turbidity in the water which is above standard levels.
- "Turbidity has no health effects. However, turbidity can interfere with disinfection and provide a medium for microbial growth. Turbidity may indicate the presence of disease causing organisms."
Where my mother lives they recently had to dig a new well and take the old one off line because of arsenic levels in the water. There is an arsenic level which is considered "safe enough," but the community still wanted a new well. One of the children knew about lead problems in drinking water from watching the news. So we discussed different substances which have interesting histories of people thinking they are or aren't safe for various reasons, including lead (which was found in paint, gasoline, and was the original Christmas tree tinsel), fluoride (which my mom had me take in pill form as a child), asbestos, and mercury (the phrase "mad as a hatter").
We continued our afternoon by reviewing The Urinary System and doing a few additional activities:
- look at the results of our Eggmosis experiment in great detail!
rinse and feel each egg one at a time -- chicken, duck, peacock -- and make observations
notice that each kind has a differently textured membrane
check to see if they bounce when you drop them (they do)
go outside and squeeze the peacock one and the chicken one until they break and see the insides flood out
feel the empty membranes and compare them to the texture of balloons
crack a regular raw egg to see that its membrane is clear and has absolutely no rubbery texture... why does the vinegar seem to make the membrane get whiter, stronger, thicker?
notice that eggs had gotten larger (pictured above)!
to confirm, compare the shell-on eggs of the chicken and duck side by side with the membrane-only versions
discuss how the water from the vinegar moved across the membrane into the inside of the egg because Nature always seeks a balance... just like the hot water in the bathtub (which gradually cools off and you get out) or muffin batter in the oven (which gradually heats up and you get tasty hot muffins)
The Nervous System
- read "Brain and Nervous System: Mission Control" chapter from Blood and Guts: A Working Guide to Your Own Insides, stopping as follows:
- at the bottom of page 112, look at "Nerve Cell," page 25 in the Human Anatomy Coloring Book
- squeeze hands and pass the squeeze along a chain of people
- at the top of page 113, look at "Nervous System," page 24 in the Human Anatomy Coloring Book
- talk about spinal cord injuries that can stop the flow of communication along the information highway and lead to paralysis... wear your seatbelts!
- in the middle of page 113, talk about reptilian brain and mammalian brain, how "fight, flight, or freeze" makes it impossible for us to use the higher level thinking processes in our frontal lobe because blood flow there is greatly reduced as more blood is sent to our primitive brain, why it's important to "take a break and take a breath" before talking things through when there's something stressing you out
- at the bottom of page 113, look at changing shape of skull
- set out and look at The Human Evolution Card Set by Clocca Concepts (pictured above)
- set out and look at tracing paper copies of skull drawings from Early Humans by Michelle Breyer, along with half gallon jars of rice showing sizes of different hominid brains
- at the top of page 114, look at "Brain," page 26 in the Human Anatomy Coloring Book
- on page 116, do Knee Jerker activity
- on page 117, do Limb Levitation activity and Dollar Drop activity
- at the top of page 119, do Your Reaction Speed activity from page 95 of Easy Genius Science Projects with the Human Body
- on page 119, do Force of Habit activity (put 3 minutes on the timer) and Training Time activity
- on page 121, do Dominance Tests activity
Note: We didn't do this but here's another interesting activity for diffusion. It requires a plastic bag, twistie-tie, water, cornstarch, iodine, and a container large enough to hold the plastic bag. Remember that you CAN'T use decolorized idiodine for these kinds of experiments. I got my true-blue iodine at Walgreens.
This post contains affiliate links to materials I truly use for homeschooling. Qualifying purchases provide me with revenue. Thank you for your support!