Tag Archives: Equipment

The New and Improved Kilogram

How do we know how much anything weighs? Where does the measurement come from when you use the kitchen scale or the scale in your physics lab? Since 1879, the sole definition of the kilogram was carefully locked away in an underground vault in France, the International Prototype Kilogram (IPK). Starting May of 2019, this tightly stored piece  of platinum and iridium will no longer officially represent the mass of a kilogram. This renewed definition will be more accessible to everyone and remain accurate for the rest of time, demonstrating the importance of this change.The kilogram is one of the base units as part of the International System of Units (SI).

The International Prototype Kilogram, or Le Grand K informally, is the only physical artifact that determines the official mass of one kilogram. However, since it is stowed away under careful protection by the International Committee for Weights and Measures (ICWM). It is hardly accessible and any changes in mass due to scratches or dirt would change the official mass of the kilogram. Even copies made of Le Grand K may not always be exactly accurate.

This prompted the change by the ICWM to a much more accessible and unchanging value based on a fundamental constant, the Planck’s constant. Planck’s constant, or h, like all other fundamental constants of nature remain the same with time and throughout the universe. Planck’s constant relates the smallest energy packet possible to the frequency of that energy packet, and is defined to be 6.626176 x 10^(-34) kilogram meter squared per second. With the kilogram within this constant, the determination of the kilogram can be made much more precisely without needing to compare it with the actual IPK.

To determine the mass with the new definition, a Kibble balance can be used. The Kibble balance is able to weigh mass against an electromagnetic current, making it incredibly accurate and precise.

Shown below is a video from Veritasium working with NIST (National Institute of Standards and Technology) explaining the new changes for the kilogram and how a kibble balance is used to determine the mass:

For the common household scale, or even anything beyond advanced physics, the new definition of the kilogram will not cause any change in mass. However over time, the required precision for mass in all fields of science will benefit from this change. The importance for consistent and precise measurements in all of science and business are seen.

— Christy Lau

Wearable Stickers: The New Life-Saving Medical Device

What if a sticker could save your life? Sometimes, the scariest part about being sick is not knowing whether you are taking all the correct measures to monitor and treat your illness, even after the doctor prescribes medication. A number of wearable devices such as wristbands have been created to monitor our physical activity and ensure that our health is on the right track. However, these devices are typically very expensive.

Recently, a team from Purdue University in Indiana published their research in ACS Advanced Materials and Interfaces on an electronic wearable sticker. These smart stickers are a simpler and more cost- efficient version of existing electronic wearable devices available for personalized medicine.

University Hall at Purdue University. Courtesy of Flickr Commons (Bill Badzo)
Source: https://flic.kr/p/suXmh8

 

Both the electronic devices and the stickers can alert users of any health risks or warning signs in real time. They contain sensors that record electrocardiograms, electromyograms and electrooculograms, which measure the electrical activity produced by the heart, the skeletal muscles, and the corneas respectively. They can also provide thermotherapeutic treatments, or heat therapy, to joints.

EPEDs demonstration video. Courtesy of YouTube. Source: https://www.youtube.com/watch?v=IuKbx3xyPIk

Purdue’s new epidermal, paper-based electronic device (EPED) can also be used as implantable sensors that monitor sleep, as they can adapt to internal organs without any serious effects. They are inexpensively paper-based and made out of cellulose. Lined with serpentine shapes, which make them more flexible and stretchable, they are coated with molecules that protect them from sweat, oil, water and bacteria as well. Each sticker costs about 5 cents to produce, and only require cheaper printers likened to those used to print books quickly and efficiently.

EPED Stickers designed by Purdue University. Courtesy of Youtube.
Source: https://www.youtube.com/watch?v=IuKbx3xyPIk

Book Printer. Courtesy of Wikimedia Commons.  Source: https://commons.wikimedia.org/wiki/File:On_demand_book_printer_2.jpg

As wearable devices become increasingly popular in this technological era, these stickers are a cheap and effective solution that makes personal health monitoring more accessible to all. Since they are so easy to implement and test, with growing research, they can be developed to accommodate a range of other healthcare needs in the very near future.

– Justine Law