Category Archives: General Science

Number of Photons Per Second from a One-Watt Bulb

Posted on 2-June-2015 by mathscinotes

An article on Stumbleupon and called "8 shocking things we learned from Stephen Hawking's book" considered the following statement from The Grand Design shocking.

A 1-watt night-light emits a billion billion photons each second. Continue reading →

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Radioactive Paper?

Posted on 13-May-2015 by mathscinotes

I just read an article article that glossy paper is also slightly radioactive, a fact that I found surprising. As I read about glossy paper, it turns out that glossy paper often contains kaolin, a type of clay. So it is radioactive for the same reason that kitty litter is radioactive, which also contains clay. Continue reading →

Posted in General Science | 3 Comments

Banana Equivalent Dose

Posted on 17-April-2015 by mathscinotes

I recently have been reading quite a bit about the hazards of traveling to Mars – one of the major hazards is radiation. This Mars reading has driven me to write a number of posts that look at the effects of radiation exposure in our daily lives here on Earth. Continue reading →

Posted in General Science, Geometry | 2 Comments

Earth With All the Ice Melted

Posted on 4-April-2015 by mathscinotes

Last night, one of my sons and I discussed using R to process geographic data. Related to this topic, we also discussed was how to visualize the impact of global sea level rise on certain countries. The video below does a good job showing what would happen if all the ice on Earth melted, which would raise sea level by ~70 meters. Continue reading →

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Natural Nuclear Reactors

Posted on 1-April-2015 by mathscinotes

I read an interesting article today about the natural nuclear reactors of Oklo, Gabon. I had first read about these reactors in a Scientific American article back in 2005. The article I read today was interesting because it did a good job presenting some of the key numbers related to uranium isotope ratios on Earth, how the uranium got here, and how natural nuclear reactors could have formed ~2 billion years ago, but probably not today. Continue reading →

Posted in Geology | 2 Comments

Species Longevity

Posted on 22-March-2015 by mathscinotes

I am always surprised when I read about how long some members of the animal kingdom live. Back in 2007, I saw an article about a bowhead whale (Figure 1) that was confirmed to have lived ~130 years. In fact, there is some chemical evidence that one bowhead whale may have lived to be 211 years old. Continue reading →

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Lake Water Clarity Over Time

Posted on 19-March-2015 by mathscinotes

I have a small summer cabin on a lake in northern Minnesota that my family uses for recreation. The health of the lake is very important to me because I plan on leaving the property to my children so that my children and grandchildren (when and if they come) will have a nice place to vacation. One way to assess the health of the lake is by measuring its clarity, which is measured using a Secchi disk (Figure 1). Continue reading →

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Use Care When Mixing Cleaning Chemicals

Posted on 11-March-2015 by mathscinotes

When I was a boy (early 1970s) I worked in a nursing home as a night janitor. At the home, we had many WW1 veterans. I will never forget one WW1 veteran who had been permanently disabled during a chemical attack. I do not know what gas he was exposed to (he mentioned chlorine gas, mustard gas, and phosgene), but I do know he had a bad case of emphysema that made his life miserable. Continue reading →

Posted in General Science | 4 Comments

Large Quantity of Manganese Nodules on the Atlantic's Seafloor

Posted on 2-March-2015 by mathscinotes

I had a deja vu moment this week. Yahoo had an article on how a large amount of manganese nodules have been found on the Atlantic Ocean's seafloor (Figure 1). Back in the 1960s, I remember reading about Howard Hughes building the Glomar Explorer to mine manganese nodules from the bottom of the ocean. It turned out this story was a CIA cover story for Project Azorian, but that is another story. Continue reading →

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Fan Airflow Versus Static Pressure Diagram

Posted on 19-February-2015 by mathscinotes

I was so happy with my previous fan installation that I am considering replacing some old fans with new, higher throughput, and quieter fans. The installations will be similar to that shown in Figure 1.

I have been using a nomograph (Figure 2) for my home HVAC calculations (example). I have decided that I am now living in the 21st century and I should figure out the formula that this graph represents. In this post, I will generate part of this nomograph to verify that I have put together the correct formula. Continue reading →

Posted in Construction, General Science | 3 Comments