New model described in the journal The Physics Teacher provides a more accurate estimate of the pack weight a given hiker will be able to carry
Hikers are generally advised that the weight of the packs they carry should correspond to their own size, with smaller individuals carrying lighter loads. Although petite backpackers might appreciate the excuse to hand off heavier gear to the larger members of the group, it turns out that they may not need the help.
While leading students on extended backpacking trips for Outward Bound, Kansas State University physics professor Michael O’Shea noticed that some of the smaller students could comfortably carry a greater pack weight than the larger ones of similar fitness levels.
The explanation, he reasoned, might have something to do with the fact that hikers must haul not only their packs, but also their own body weight. He incorporated both of these variables into a model described this week in the journal The Physics Teacher, published by the American Association of Physics Teachers (AAPT). The model provides a more accurate estimation of the pack weight a given hiker will be able to carry and an example of how real-world modeling examples can be used in the classroom.
“Online advice from several sources was somewhat misleading in suggesting that pack weight should be a certain percent of a person’s weight,” said O’Shea. However, as the size of any animal increases, strength increases more slowly than body weight—the reason why tiny ants can carry a disproportionately heavy load compared to their weight.
He combined this information with body scaling proportions obtained from other research to create a model matching his observations. The resulting equation takes into account the hiker’s entire load—backpack plus body weight—and can be used to determine the maximum backpack weight for an individual of a given size.
“Overall strength of an individual does not determine how heavy a backpack a person can comfortably carry,” said O’Shea.
The model does make a few assumptions—namely, that the hikers being compared have similar body-fat percentages, and thus that increase in size does correspond to a proportional increase in strength. Nevertheless, it provides a more nuanced estimation of hikers’ carrying capacity than does a simple proportion of body weight.
O’Shea’s model could help inform hikers’ packing decisions, but it also fits into the classroom: “Students should be able to see how some aspects of complex systems, in this case the frame of a human being, can be modeled in a relatively simple way to extract useful information,” he said.
The article, "Backpack Weight and the Scaling of the Human Frame," by Michael O'Shea, appears in the journal The Physics Teacher on Tuesday, October 21, 2014. After that date, it can be accessed at: http://dx.doi.org/10.1119/1.4897584
ABOUT THE JOURNAL
Dedicated to the strengthening of the teaching of introductory physics at all levels, The Physics Teacher provides peer-reviewed materials to be used in the classrooms and instructional laboratories. See: http://scitation.aip.org/content/aapt/journal/tpt
Jason Socrates Bardi | newswise
Study offers new theoretical approach to describing non-equilibrium phase transitions
27.04.2017 | DOE/Argonne National Laboratory
SwRI-led team discovers lull in Mars' giant impact history
26.04.2017 | Southwest Research Institute
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
27.04.2017 | Life Sciences
27.04.2017 | Physics and Astronomy
27.04.2017 | Earth Sciences