Thursday, May 26, 2011

CSB #8:Relation Between Oxygen Levels and Grip Strength

by: Eric Yu, Harry Xu, Albert Lin, and Chris Hildum

Summary: 
The purpose of our experiment is to find out if the amount of oxygen someone has affects their strength. If oxygen levels do have a relationship with strength, we want to find out at how many seconds someone starts to lose strength. A scenario where our experiment comes into play is when a person is trapped in a place with limited oxygen; we want to find out if the person will be able to lift heavy objects in order to escape. In our experiment, we used Logger Pro to record our data in a graph on a laptop. Other materials we used are a paper bag for each test subject, a Hand Dynamometer for measuring the force in Newtons before and after hyperventilation, and a Go Link Cable. In order to simulate the lack of oxygen, we made someone breathe rapidly into a paper bag and hyperventilate for periods of 10 seconds and 20 seconds. Our first trial was when the test subject squeezed the Hand Dynamometer for 5 seconds. Then, he would hyperventilate in the paper bag for 10 seconds and squeeze the Hand Dynamometer again. We would measure the force of the test subject before and after hyperventilating. The second trial for our test subjects is that they would squeeze the Hand Dynamometer for 5 seconds, hyperventilate into a paper bag for 20 seconds, and squeeze the Hand Dynamometer for 5 seconds again. Some possible variables in our lab are that the time each person squeezes the Hand Dynamometer and hyperventilates into a paper bag may be different for each person. Also, some people who were our test subjects may be stronger than others, thus having a stronger force than everyone else.

Before Harry hyperventilated, he was able to emit a force of 197.4 Newtons. After, hyperventilating for 10 seconds, his strength had decreased by 48.5 N.  However, when Harry hyperventilated for 20 seconds his strength only reduced by 15.4 N. The results for Eric and Albert were similar to Harry’s. This is because when they hyperventilated longer, their strength did not decrease as much compared to a shorter hyperventilation time. When Chris hyperventilated for 10 seconds, his strength was reduced by 3.8 N, but when he hyperventilated for 20 seconds, his strength was reduced by 12.6 N. Chris' results were slightly different compared to the others since his strength decreased steadily as his oxygen supply decreased. We also found that the average decrease in strength for 10 seconds was about a 21.8% decrease. The average decrease in strength for 20 seconds was about a 13.4% decrease. With the given results, the strength of most people increased as they had a lower amount of oxygen. However others had a decrease in strength with a lower amount of oxygen. This could be possible if the brain believes the human body is in danger. This way, adrenaline would be sent out throughout the body. Because of this, some people would have an extra amount strength. However, for some other people, the adrenaline can be sent out later than others. This explains why some people have lower strengths with a lower supply of oxygen.Results: 
-Harry 
10 sec:

Highest before hyperventilating: 197.4 Newtons
Highest after hyperventilating: 148.9 Newtons
20 sec:


Highest before hyperventilating: 179
Highest after hyperventilating: 163.6

- Eric
10 sec: 
Highest before hyperventilating: 205.9 Newtons
Highest after hyperventilating: 151.9 Newtons
20 sec:

Highest before hyperventilating:190.3 Newtons
Highest after hyperventilating: 155.5 Newtons
- Albert
10 sec:
Highest before hyperventilating: 195 Newtons
Highest after hyperventilating: 130.7 Newtons
 20 sec:
Highest before hyperventilating: 212.7 Newtons
Highest after hyperventilating: 172.6 Newtons
- Chris
10 sec:
Highest before hyperventilating: 182.6 Newtons
Highest after hyperventilating: 178.8 Newtons
 20 sec:
Highest before hyperventilating: 187.1 Newtons
Highest after hyperventilating: 174.5 Newtons

Saturday, May 7, 2011

CSB#7: The Domestication of Dogs

Dogs were the first animals to be domesticated. At first, dogs were first believe to have come from jackals, but the idea was discarded after the idea that they originally came from grey wolves. However, biologists and archaeologists still debate how gray wolves first evolved into becoming the dog breeds that is known today. Some theories are that dogs were domesticated for food, companionship, or for their amazing ability to hunt. In order to find where domesticated dogs had originally come from, scientists took DNA from 1,500 dogs. They soon found out that most of the DNA were similar to the Near Eastern gray wolf.

I was interested by the fact that different breeds of dogs are found all over the world, but they all came from one species, the Near Eastern gray wolf. The wolves must have been caught by humans and bred for food, companionship, or for their hunting ability. This way, the wolves would be more similar to the way dogs act today.

Citations:
Jarrett, Lobell A., and Eric A. Powell. "More than Man's Best Friend (cover
     story)." Archaeology: n. pag. EBSCO Animals. Web. 7 May 2011.
     <http://puffin.harker.org:2092/ehost/
     detail?vid=3&hid=105&sid=30471ac1-26f6-46ea-95a1-1b0eb73c1ea2%40sessionmgr110&bda
     ta=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=sch&AN=52898691>.



http://a6.idata.over-blog.com/312x468/0/34/63/78/husky.jpg