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Any good biology experiments for ages 10 -16?


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Do any have you have ideas for good nature and biology related projects for young people? I regularly write articles about nature related activities for a nature magazine. I have recently exhausted my ideas for articles, and was wondering if any of you knew of great demonstrations that demonstrate a certain aspect of how nature works.


The activity should be for ages 10-16 and should only require easily obtainable items. I have a more detailed description of what I am doing and looking for on my website at http://www.geeksbrain.net/Projects/projects.html.


Thanks in advance,

to all of you who have brainy ideas

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  • 2 weeks later...

The effects of temperature of fermentation


Fermentation = water + sugar + yeast.


Make 1 batch, divide into three clean and loosely-covered soda bottles (to allow the CO2 to escape). Ferment for a week at different temps, possibly: (1) cooler than room temp (sitting in an ice bath?), (2) room temp and (3) more than room temp (container placed on/wrapped in those iron-oxygen hand warmers?).


((PS – Ice and hand warmers are relatively safe ways for kids to generate cold and heat. I think the ice would need replacing at least twice daily, and I think that those hand warmers last most of the day.))


On the cheap, the “cool” container could simply sit in the frig, and the “warm” container could sit on a radiator.


During the week, determine activity of fermentation in the containers. Fermentation produces a “churning” caused by the yeast generating carbon dioxide bubbles that rise to the surface. Ideal temperature for baker’s yeast is about the same “biological” temperature as for humans and most other life: that is, warm (~98.6°F/37°C) but not hot. Thus, the ice bath should produce the least activity, and the room temp and “warm” fermentations should produce the greatest activity.


This carbon dioxide also makes the so-called “air” pockets in fermented bread. The word “ferment” comes from the Latin fervere meaning “to boil or seethe”.


You would need to determine the proper amounts of water, yeast, and sugar and to see if one week is enough to produce a vigorous fermentation. From childhood, I remember that was about the right time.


The effects of pH of fermentation


A similar experiment can determine the proper pH for fermentation, using plain water and water spiked with vinegar (acidic) or baking soda (alkaline). The answer is that the “biological” pH would be, not surprisingly, approx. neutral pH (~7, plain water).

Merged post follows:

Consecutive posts merged

Proteins, protein folding, solutions, and protein-folding diseases


Proteins are molecules composed of chains of amino acids that fold into particular shapes due to their composition of amino acids and their environment.


Instruct kids to use a magnet on one-foot piece of stainless steel pull chain for lamps. (Make sure they buy the stainless steel pull chains because the brass ones aren't magnetic. Bring a magnet to the hardware store to test it.) Notice how the little balls stick to each other, although not in a particular shape.


Attractive forces within proteins are similar, but water repels certain amino acids (as if they were oil) and usually pushes them in where they become folded inside the protein. Certain other amino acids are attracted to water and are often drawn to the surface and end up on the outsides of proteins. This repulsion is also what prevents water and oil from mixing. Kids can put drops of cooking oil in some water to see how they don’t mix. A protein’s amino acids and surface contour are critical to their function in the chemistry of life. Folded properly, proteins can remain in watery solutions, such as bodily fluids, and perform their jobs. (Wikipedia shows nice two-dimensional “unfolded” and “folded” drawings of a theoretical protein.)


Demonstrate what happens sometimes when proteins aren’t folded properly, which is, proteins can expose their water repelling amino acids to the water, and thus, “come out of solution” – that is, bodily fluids reject them in the same way that water rejects oil droplets. Changing the pH (acidity) of a solution can cause proteins to distort and unfold. So, add some vinegar to some milk (I’m not sure how much), and watch the milk protein called casein come out of solution and clump together. These proteins are no longer “dissolved” in the liquid.


When some people’s genes make some proteins incorrectly, they don’t fold properly and don’t work well. This causes “protein-misfolding diseases” like sickle cell anemia, cystic fibrosis, and LSDs -- the Lysosomal Storage Diseases, which include Tay-Sachs, Gaucher, Fabry, and Niemann-Pick. Because these diseases are genetic, they afflict children from an early age, and typically cause an early death. These diseases are very obvious, and people are either born with a protein misfolding disease or not -- we don’t want to give kids nightmares that their proteins might suddenly start folding improperly. Many of these misfolded proteins come out of solution and don’t work as they should, and this results in the “disease”, which obviously is not contagious. So there's no need to fear people with these diseases.


Cystic fibrosis: a disease of altered protein folding


Protein folding

Edited by ewmon
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  • 4 months later...

My 10 year-old cousin enjoyed this one the other week at school: put porridge into a stocking as if it were food in an intestine and demonstrate peristalsis. This also demonstrates how nutrients get absorbed through the intestinal wall (some particles get squeezed out through the stocking) and how fibre continues through the intestine and colon and comes out as poo! Sounds like fun.

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