Approximately 50,000 people ran and walked down the street past my home in the 33rd annual running of the 10-km Bolder Boulder footrace on the morning of Memorial Day, May 30, 2011. In addition to the serious runners, there were many individuals dressed in all manner of amusing festival costumes; some were jogging and some were walking. Early in…

Two recent articles make prominent use of the concept of "apparent weight." The concept of "apparent weight" leads to two confusing inconsistencies. We need to know that with very little change in our representations, we can give our students an improved understanding of "weight" without ever having to invent the appealing but confusing concept of…

The following is a petition written over 36 years ago by University of Colorado students to the seven members of Colorado's delegation to the United States Congress. I was advisor to the student groups and found this when cleaning up my university office. It strikes me as being amazingly farsighted.

On Dec. 27, 2006, we drove with our children and their families to a cabin we rented on the grounds of the "YMCA of the Rockies" in Estes Park, CO, for a few days of winter relaxation and recreation. On the night of the 27th a snowstorm dropped over half a meter of new snow, creating a beautiful winter wonderland. For the next couple of days the…

The article "Torsional Oscillations with Lorentz Force" by Paul Gluck provides a glimpse into the major world of ancient physics demonstrations in the late 19th and first half of the 20th centuries. The apparatus that was described and similar pieces of apparatus are the basis for many memorable but long forgotten educational demonstrations. The…

Reviews the concepts behind atmospheric optical phenomena such as rainbows and anticrepuscular rays. Describes the experience of observing these two phenomena simultaneously and calculates the probability of that observation. (JRH)

Discusses issues related to perpetual population growth. Argues that if we believe that there are no limits to growth, we will have to abandon the concept of a spherical Earth which puts limits to growth. (JRH)

Demonstrates that the number of kilometers of highway in the U.S. tends to grow exponentially and discusses what can be done to modify this growth. (MLH)

Discusses the use of the exponential function in the compounding of interest. (MLH)

Examines the mathematics of the exponential function and some examples of its application in analyzing inflation. (MLH)

Discusses the postage rate increases in recent years and notes that if the trend continues the rate will reach three dollars an ounce by the year 2017. (GA)

Presents part eight of a continuing series on the exponential function in which, given the current population of the Earth and assuming a constant growth rate of 1.9 percent backward looks at world population are made. (SL)

Comments on a news item on rail traffic that is meant to promote conservation of energy. (GA)

Discusses energy consumption of electric and battery operated electronic clocks. (SL)

Presented is the second of a two part series on the use of exponential functions. Discussed, with examples, is the exponential growth of compound interest problems. (SL)