Heart and Lungs

Today we discussed the lungs and heart.

One of the strangest things about the lungs is they aren't directly connected to the chest. What keeps them in place and allows them to inflate is the power of nothing - or vacuum. As long as the chest cavity is sealed, the outside of the lungs is stuck tight to it. And despite having two lungs, puncturing the seal on either side will cause both to collapse as the vacuum fails, because both lungs are in the same single cavity. Evolution, unfortunately, is brainless and can't make obvious fixes. For homework, try and think about the body. Can you think of any improvements that would make the human body work better?

And for more on the amazing power of vacuum, here's an MIT video going through the history of vacuum.

More Heredity

Some new links! Soldier on, heredity students, the end is in sight.

Vocab:
http://www.biology.arizona.edu/vocabulary/mendelian_genetics/mendelian_genetics.html

Quiz stuff:
http://www.biology.arizona.edu/human_bio/problem_sets/human_genetics/human_genetics.html
http://www.biology.arizona.edu/human_bio/problem_sets/color_blindness/color_blindness.html
http://www.proprofs.com/quiz-school/quizshow.php?title=genetics-practice-test&quesnum=1
http://www.biologycorner.com/quiz/qz_advanced_genetics.html

Also, you can brush up on epistatis if you feel up to it: http://www.csun.edu/~cmalone/pdf360/Ch04-2extensions.pdf but it won't be on the regional test.

Crystals, Acids, and Digestion

Hi everyone!

It's been a busy few weeks. The borax crystal necklaces are finally complete and home with everyone. Two weeks ago, we explored the pH of common substances with a color changing indicator and learned that foods tend to be sour (acidic) and non-foods bitter (basic).

To show the effects of acids and bases on inorganic and organic material, we examined eggs. The kids first investigated century eggs, which are raw duck eggs that have been cured in lye for several months, then dunked fresh chicken eggs in vinegar to see what happened.

From there we moved on to our own digestive system and how food is processed. The human digestive system contains both acidic (the stomach) and basic (small intestine) sections, as well as a lot of other features shown on the worksheet. Make sure that's finished for next week, when we'll be finishing up digestion and focusing on enzymes.

Also, while not related to our current topic, here's a video of a juvenile (note the mouth color is pink) raven seeking human aid after getting several porcupine spines stuck in its face (ravens enjoy pulling the tails of other animals, which is probably how this happened).



Ravens are very intelligent and can teach their young to distinguish between friend and foe. This raven's parents must have been helped by a human or seen a human helping another raven and taught it to go to humans for help.