Letter demonstrates need for basic physics

I would like to respond to Brian Danker's idea about global warming. While I applaud his scientific approach, I believe his logic is wrong. The surface level in a glass of ice water does not go down when the ice melts - it stays the same. That's a moot point, though, because the vast majority of the planet's ice is on land anyway

Archimedes had the following useful realization: The weight of the water that a floating object displaces equals the weight of the object. Simple: Weight of displaced water equals weight of floating object. The amount of displaced water does not depend on the shape or density of the floating object - only on its weight. A melted iceberg displaces just as much water as a frozen iceberg.

The vast majority of the planet's ice is not in the form of floating icebergs, though it is in the glaciers. Glaciers do not displace water since they are located up out of the ocean on land (they're still in the ice tray). Melting glaciers could have an effect on sea level, not melting floating icebergs.

This serves as one example of why normal people should have at least a basic understanding of physics. People are going to try to sell you ideas, and you need to be able to weigh them. Lately, I have seen numerous examples of our leaders making decisions based on feelings, bias and gut reactions. Such a rejection of rational thought is a threat to our way of life. Therefore, I commend Brian Danker on his attempt to think about issues rationally. However, I believe Brian has made a mistake in his reasoning.

Ben McMorran
physics graduate student

Archimedes' Principle misunderstood in letter

Brian Danker's recent letter about global warming claimed that the water level in a glass will drop once the ice floating in it melts.

Unfortunately, that is completely false. Archimedes' Principle states that an object wholly or partially submerged in a fluid feels an upward buoyant force equal to the weight of the displaced fluid. When this principle is applied to the floating ice, it means that once the ice melts it will occupy exactly the volume under the water surface that used to be ice.

Thus, the water level will not change. You should try the experiment and see what happens. Since he used that argument as the basis for his letter, the rest of his letter is irrelevant. It is definitely sad that a principle discovered so long ago is still misunderstood by so many people.

Drew Milsom
lecturer, department of physics

Calling people ignorant doesn't help

It is good to see Miss Raz get on her high horse and claim we need to "get out of our American bubble" and speak about how our "ignorance" lets people in the Third World go without aid and an early warning system. Let's talk about such statements.

The whole reason why no such system exists is because there hasn't been a major tsunami to hit in the Indian Ocean in more than 100 years, and most of the more devastating tsunamis do not hit in the Indian Ocean area. Furthermore, her claims that we should "understand that extreme poverty inevitably leads to catastrophes" are also pointless. There was no early warning or emergency broadcast system in many different countries affected by the tsunami. Yes, if there had been one, there might have been many, many fewer lives lost. But is it our responsibility to build these systems?

One begins to question where the line is between the responsibilities of the United States and the responsibility of said country to take care of their own people. Don't get me wrong. I'm not going to downplay the significance or the magnitude of the disaster. I am all for helping in with the disaster in Asia. I've made my donation, and I have seen countless others make significant contributions to aid the people involved in this tragedy. Before one calls us ignorant or otherwise unwilling to help, one must also consider who we are. This is the United States of America, also known as the defender of the little guy, the world's police force and one of the largest donors to foreign aid in the world. The disaster in Asia was preventable, but writing inflammatory remarks about how the disaster is the result of "your ignorance" does nothing to help the cause.

Christopher P. Robbins
electrical engineering sophomore