Category Archives: General Science

Air Conditioning Load of a Group of People

Posted on 12-June-2018 by mathscinotes

I was reading an article about HVAC (Heating, Ventilation, and Air Conditioning) calculations in the Journal of Light Construction that had a quote I found interesting. It said that

… 17 extra occupants added more than a half ton of cooling load. Continue reading →

Posted in Construction, General Mathematics, General Science | Comments Off on Air Conditioning Load of a Group of People

Colonoscopy Notes

Posted on 28-March-2018 by mathscinotes

I had a colonoscopy yesterday and it was a great learning experience. I am fortunate that the anesthetic they gave me had little effect, and the doctor was open to answering questions from an inquisitive patient. It probably helped that the doctor was a mechanical engineer that decided to go into medicine – we had lots to talk about. I found it funny when he mentioned that he did not like engineering work on optics – of course, much of my life has been spent designing optics. In the course of this doctors daily work, he uses optics all day long. His gear was from Olympus, some of which is manufactured in Brooklyn Park, Minnesota, which near my home. Minnesota is known for its medical technology. Continue reading →

Posted in General Science | 3 Comments

Dealing with Furnace Condensate At Low Temperatures

Posted on 2-January-2018 by mathscinotes

While working on my retirement home and workshop in northern Minnesota, I have noticed that my furnace is generating between five and seven gallons of condensate per day. The furnace is on quite often this time of year because the outside temperature is running about -30°F (-35°C). I currently pipe the condensate over to a floor drain, which is connected to my septic system. Continue reading →

Posted in Construction, General Science | 13 Comments

Examples of Lake Clarity Variation Over Time

Posted on 13-September-2017 by mathscinotes

I am having my cabin built on a small lake in northern Minnesota. At the same time that the cabin is being built, a friend is in the process of locating an an existing cabin for purchase on a nearby lake – there are dozens of lakes within a few miles of my building site. He has been asking questions about the clarity of the water in these lakes. Fortunately, the state of Minnesota has an excellent web page with all sorts of technical data on lake water, including clarity measurements. Professional lake monitors are also used. On a regular basis, they gather technical information on the lakes: chemistry, fish populations, presence of invasive species, etc. The lake water clarity data historically has been measured using a Secchi disk (Figure 1) and volunteer lake monitors. In recent years, satellites have been tasked with clarity monitoring as well. So there are now two sources of lake clarity information that can be used to cross-check one another. Continue reading →

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Iceberg Size Analogies

Posted on 14-July-2017 by mathscinotes

e nightly news reports have been filled with stories about the large iceberg that recently calved off of the Larsen C ice shelf. Reports of natural events always struggle with trying to convey the scale of events to the general public. In this case, the media has been reporting that the iceberg is (1) approximately the same area as the state of Delaware, (2) it contains a volume of water that is double that of Lake Erie, and (3) the mass of water it contains is about 1 trillion metric tons. Figure 1 shows a good graphic for area comparisons. Continue reading →

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CO2 Generation By Fuel Per Million BTUs of Heat

Posted on 7-July-2017 by mathscinotes

My year-round cabin in northern Minnesota needs a furnace, and a furnace needs fuel. My fuel options are fairly limited – fuel oil, liquid natural gas, or propane. I ended up choosing propane because the local propane gas supplier has a reputation for being reliable. While researching the fuels, I became curious about the amount of CO2 released into the atmosphere by the different fuel options for given amount of heat. Continue reading →

Posted in Construction, General Science | 1 Comment

Daily Tree Consumption for Toilet Paper

Posted on 15-February-2017 by mathscinotes

I was reading an article on National Geographic when I spotted an interesting factoid about the impact of Toilet Paper (TP) world-wide tree consumption.

Toilet paper wipes out 27,000 trees a day.

Like many factoids, I doubt there is a way to actually measure this number – it can only be estimated. Thus, it is a prime candidate for a Fermi solution. Continue reading →

Posted in General Mathematics, General Science | 7 Comments

Effect of Earth's Curvature on Suspension Bridge Dimensions

Posted on 25-January-2017 by mathscinotes

I have received a number of questions recently on how the curvature of the Earth affects building construction. In general, the effects of the Earth's curvature are ignorable because most man-made construction is on too small of a scale to notice the effects of the Earth's curvature. One well documented exception is the Verrazano-Narrows bridge, whose design took into account that the bridge towers are 1 5/8 inch farther apart at the top than at the bottom. In this post, I will show how to compute this value. Continue reading →

Posted in Construction, General Science | 28 Comments

Larsen Ice Shelf and Potential Sea Level Rise

Posted on 23-January-2017 by mathscinotes

I just read an article about a large iceberg that will likely form in 2017 when a 5,000 km2 section of the Larsen C ice shelf (Figure 1) calves into the Antarctic Ocean. There is concern that the formation of this iceberg will remove a barrier that has been preventing the entire Larsen C ice shelf, with a total area of over 50,000 km2, from sliding into the sea. This is a massive amount of ice. Continue reading →

Posted in General Science, News Fact Checking | 2 Comments

Calorie Per Acre Improvements in Staple Crops Over Time

Posted on 4-January-2017 by mathscinotes

My family has strong agricultural roots – mainly in dairy and potato farming – and our holiday conversations frequently turn to discussions of crop yields (bushels per acre or lbs per acre). As I listened to the discussion between my brothers on this year's crop yields, I realized that the yield numbers they were quoting were much higher today than we saw as children. This made me curious, and I decide to go out to the US Department of Agriculture's National Agricultural Statistics Service crop database and download CSV files on the yield of some key staple crops for processing by Power Query (i.e. recently renamed Get and Transform). I will be using this file to train my staff on defining Power Query functions. No macros were used in this analysis. Continue reading →

Posted in Excel, General Science, History of Science and Technology, History Through Spreadsheets | 5 Comments