Acid Rain

Look at the above picture. Saigo-san, why are you weeping? It shows a bronze statue of Japanese warrior Takamori Saigo (1827-77) in Tokyo's Ueno Park. It looks as though he is crying. Wonder why?


To understand about acid rain, you have to have a basic understanding of pH. pH is use to denote the concentration of hydrogen ions (H+ ) in solution. The pH factor, is a readable introduction into the topic. pH ranges from 0 (zero) to 14. The lower the pH (the higher the concentration of hydrogen ions), the more acidic the solution. pH Table illustrates the scale with examples of substances and their pH's. Bear in mind that going from pH 2 to pH 1 represents a 10-fold increase in hydrogen ions. A substance with pH 1 has 10 times the amount of hydrogen ions as a substance with pH 2. Another site, which gives essentially the same information is The pH Scale. If you want to delve more deeply into the topic of pH, look at The pH-Acid/Base Tutorial.


Acid rain is a term one hears often, but what exactly is acid rain? British Chemist Robert Angus Smith first used the term "acid rain" in 1872 in a book entitled Acid Rain: The Beginnings of a Chemical Climatology. U.S. Environmental Protection Agency's web site explains that a better term would be acid deposition-the return to earth of acid pollutants in the atmosphere by either wet or dry means. Wet deposition is sometimes termed acid precipitation (rain, hail, fog or snow with a pH value of less than 5.6). Dry deposition is acidic gases and particles falling back to earth.


Origins of acid rain.

So what causes acid rain? Simply put, acid rain is cause by human activity and sulfur and nitrogen are the two elements mainly responsible for the harmful effects. Take a look at the web site acid rain. Unpolluted rainwater is slightly acidic due to the presence of dissolved CO2 (carbon dioxide), NO (nitric oxide), and SO2 (sulfur dioxide), which occur naturally in the atmosphere. However, it is NO and S02 from anthropogenic or human made sources that cause the problem. Car exhaust and the burning of fossil fuels adds greatly to the amount of NO and SO2 in the atmosphere thus decreasing the pH (or increasing the acidity) of rainwater.


Is acid rain a problem? The effects of acid rain can be seen on our lakes and streams (or lake, rivers and streams), forests (or forests), building, monuments, tombstones, bridges and statues and even our health.

Is there anything that you can do to reduce acid rain emissions? Environmental Canada web site has some suggestions.

Rubber Bands

Did you know you could have a lot of fun with a rubber band? If not, read on.

Can you build a catapult using a rubber band? Check out suggestions for a rubber band catapult and see. There is a simple design for constructing a catapult with some suggesting for testing it. See what you can learn from a rubber band catapult.

What about employing a rubber band to compare relative levels of ozone in various locations? This activity uses the high oxidation capacity of ozone, which can cause a rubber band to break down in a short period of time, to estimate the ozone level at the particular site. The experiment consists of placing a rubber band around a jar and putting them in different spots. The rubber band is observed over a period of time for changes, such as cracking or pitting. Then conclusions are drawn regarding the level of ozone in each area.

Sound and a rubber band? Is there a connection here? Yes! Check out Amplifying Sound and make a rubber band-can or harpsichord. Also, look at NASA’s site sound box.

Rubber bands can be used to make a tabletop earthquake generator . What do you want with an earthquake generator, you ask? Well, how about constructing different kinds of buildings then using your earthquake generator to determine which one will best survive a quake?

How about using rubber bands to illustrate Newton's Second Law of Motion ? Newton's Car provides directions for the construction of a slingshot that propels a wooden block resting on top of a car forward thus causing the car to roll backwards. See how increasing the number of rubber bands and the weight of the car affects how far the car travels.

Make your own toys using rubber bands? Sure! The Mechanical Toy Page has several toys that one can make using rubber bands. Check out "Cotton-spool tank", "Mouse trap car" and "rubber band gun".

Can a rubber band help one to understand Edwin Hubble's discovery that all galaxies in the universe are moving away from us and the further away the galaxy is, the faster it is moving? Hubble Constant: The Effect of Distant on Speed is an interesting web site. Check it out and see what you think.

What happens to a rubber band when you heat it?

Have you noticed that if you stretch a rubber band, it does not return to its original shape afterwards? This property of a band is called hysteresis. It can be used to calculate the amount of energy lost by the rubber band.

Mars needs rubber*. Are you up to the task?

This is just a sampling of some of the fun you can have with a rubber band. I am sure you can find more.

*requires Adobe Acrobat Reader, a free download.

Dissection Anyone?

Who hasn't dissected a frog in school? Yuck. The frog had to be pithed (a needle stuck in the back of the frog's head to destroy it central nervous system so it is essentially dead). The instructor usually pithed the frog. I refused to do it. Then the poor thing was dissected. I don't know how I ever did it or why. It seems so cruel. But now, web sites exist which illustrate dissections of various animals providing an alternative to the actual dissection of animals in the classroom.




Frog


If you are learning about the anatomy of a frog, here are two excellent sites. On the first Net Frog , both a pithed and preserved frog are dissected. You get complete instructions, movies, pictures, and frog facts. The major organs are outlined so you can identify them. Also check out the virtual frog dissection kit. A click of the mouse and the skin is removed revealing the skeleton and internal organ. Click the mouse again and the heart is gone.


Skeleton of a frog.

Another excellent site is the Exploratorium. Here you can view the dissection of a cow's eye. That is something I never did in school. It has a cow's eye primer that teaches about the various parts of the eye as well as the dissection. Also on the Exploratorium site is the dissection of a sheep's brain . Learn how the brain interacts to perform cognitive and memory functions. A great educational learning sites for students.

The Thinkquest site, dissects a cat. This is something I wouldn't be able to do at all, even if required. The site states that the company the cat was brought from obtains all their preserved specimens in a responsible manner. Hmmm. Still, if you are a cat lover, approach the site with caution or not at all. It did upset me.

Overall, web sites demonstrating dissections are definitely a kinder way to learn about the anatomy of a given animal and great if you are squeamish. It also cuts down on the number of animals used for research purposes.

If you are interested in other alternate methods to dissection, check out National Anti-Vivisection Society (Vivisection: The act of cutting into or dissecting the body of a living animal, especially for the purpose of scientific research) web site. They will provide free of charge computer programs and models to substitute for the use of once-live animals in classroom dissection exercises.