Current Events: Can a Solar Eclipse Really Blind You?

        Though many have not seen a solar eclipse, it is said that it's dangerous to see it with the naked eye. This statement is true, however it is also said that staring at a solar eclipse can blind you. This statement, is false. When watching a solar eclipse, the damage you can do to your eyes is often painless, so people won't even realize they're injuring themselves which can leave a long-term effect without blinding you. 
        This condition is called solar retinopathy. Solar retinopathy is usually caused by the staring at the sun, regardless of the phase, but people can stare at the sun for so long without pain and this happens occasionally. "But during a solar eclipse, more people are at risk. With the sun partially covered, it's comfortable to stare, and protective reflexes like blinking and pupil contraction are a lot less likely to kick in than on a normal day". 

       Scientists do not have a good aim on the currency of eye damage after a solar eclipse. But in one of the studies that were conducted in the year 1999, after a solar eclipse in Europe, forty-five patience with possible solar retinopathy came to an eye clinic after viewing the eclipse. Forty were confirmed to have some kind of damage or symptoms and five had visible changes in the eye. Twenty of the patients also reported eye pain while the other twenty reported problems with vision.

        Research has also shown that while many of the damage may heal, some may be permanent. So while it might be tough to go completely blind by looking at a eclipse, doing it without the right protections could leave a long-lasting injury on one's vision. "The only safe way to view an eclipse, according to NASA, is to use specially designed sun filters, often available at telescope stores, or to wear No. 14 welder's glasses, available at welding specialty stores. 

  This information is very helpful to me. Though I have never seen a solar eclipse before, I have always thought that you could go blind if staring at one with the naked eye. This will also help if I ever see a solar eclipse, because then I will know what to do in order to keep away from damage to my eyes. This information can also help others in order to keep them away from damaging their own eyes as well, and if they suspect something, they can get it checked by a doctor.


Sources:
http://www.livescience.com/20433-solar-eclipse-blind.html
http://www.hoydalsvik.net/astrofoto/eclipse2008/index.html
http://eye-make-up.tumblr.com/colours

Collapsing Can Lab- Class Response

       After drinking a can of soda, many just crush the can and throw it out in the garbage. However, have you ever thought about the air pressure you apply to it? To understand it better, try the collapsing can lab.
       Procedure:
1. Fill a bowl with cold ice water.
2. Heat a hot plate or stove.
3. Fill a soda can with a little bit of water and wait for the water to boil.
4. When the water boils, a cloud of condensed vapor will escape from the opening in the can.
5.Allow the water to boil for about thirty seconds.
6. Using tongs, grasp the can and quickly, and carefully, invert the can and invert it into the bowl of ice water. The can will collapse almost instantly. 


       What Caused the Can to Collapse?

When the can was heated, it caused the water in it to boil. The vapor from the boiling water pushed air out of the can. When the can was filled with water vapor, it cooled suddenly by inverting it in ice water. Cooling the can caused the water vapor in the can to condense, creating a partial vacuum. The extremely low pressure of the partial vacuum inside the can made it possible for the pressure of the air outside the can to crush it.

   A can is crushed when the pressure outside is greater than the pressure inside, and the pressure difference is greater than the can is able to withstand. For instance, you can crush an open aluminum can with your hand. When you squeeze on the can, the pressure outside becomes greater than the pressure inside. If you squeeze hard enough the can collapses.

  Usually, the air pressure inside an open can is the same as the pressure outside. However, in this experiment, the air was driven out of the can and replaced by water vapor. When the water vapor condensed, the pressure inside the can became much less than the air pressure outside. Then the air outside crushed the can.

  When the water vapor inside the can condensed, the can was empty. You may have expected the water in the bowl to fill the can through the hole in the can. Some water from the bowl may do this. However, the water cannot flow into the can fast enough to fill the can before the air outside crushes it.

Source:

http://jetsfan21.blogspot.com/2010/04/collapsing-can-lab.html

Current Event; The Bigger the Eyes, the Faster the Beast, Study Finds

        Everyone know that cats, like cheetahs and lions, are one of the fastest animals on Earth. However, no one really wondered why. Study's show that their eyes are what helps with their speed, mainly because it helps with the detail vision, and the vision in dim light.
     With this in mind, studies show that animals with larger eyes allow them to run faster. Because animals need better vision in order to run, larger eyes benefit acuity and sensitivity, allowing them to run faster.
     So if you look closely into fast animals, such as horses, they have large eyes, so it gives them the better vision to avoid collision into other objects when moving quickly.
     Scientists then wanted to figure out what influences the eye size. So they collected measurements of eye size, body size, and speed in running from fifty animals. They then found that eighty-nine percent of the animal's eye size variation was due to the body mass and their maximum running speed. However, body size always influences eye size. So "an elephant is always going to have bigger eyes than a mouse." Then, the researchers adjusted for body size and then found that when looking at maximum running speed in isolation, or when you keep the body mass constant, speed is still greatly related to the eye size. Therefore, speed in animals depend on their eye size.
     However, this theory and observation does not apply to humans. So "at least in the case of humans, it's safe to conclude that fast running was not the selective factor that led to the evolution our large eyes."
     I personally never thought about something like this. I knew that certain animals were faster than others, but I never tried to relate it to eye size. This information is beneficial to me, because now I understand why certain animals have certain characteristics. This information can also benefit scientists in the future, mainly because if we were to discover a different animal, or learn more about different species of animals, knowing this will help, even if it's a small detail.


Sources:
http://www.livescience.com/20062-eye-size-running-speed.html
http://www.rachelinafrica.com/
http://animalszooguru.blogspot.com/2009/04/beautiful-white-horses-wallpapers.html