Using marinated eggs to demonstrate diffusion
Experiment designed for home or classroom shows how time, temperature
affect diffusion

Date:
March 23, 2022
Source:
American Institute of Physics
Summary:
Researchers were inspired by marinated eggs to demonstrate how
diffusion works in an easy and quantifiable way. The basis of
the recipe is marinating hard boiled eggs in vinegar or brine,
which cures the eggs by sufficiently saturating the egg whites via
diffusion. In their experiment, the researchers compared penetration
levels of red food dye in the whites of peeled hard-boiled eggs
at three different temperatures: refrigerator temperature, room
temperature, and in a cool convection oven.



FULL STORY ========================================================================== Marinated, or pickled, eggs are enjoyed by cultures around the
world. There are Pennsylvania Dutch red-beet pickled eggs, German-style
ones with a heavy dose of mustard, and Asian recipes that use rice
vinegar and soy sauce, to name a few.


==========================================================================
The basis of any recipe is marinating hard boiled eggs in vinegar or
brine, which cures the eggs by sufficiently saturating the egg whites
via diffusion.

In American Journal of Physics, published on behalf of the American
Association of Physics Teachers by AIP Publishing, researchers at the University of Nebraska-Lincoln were inspired to demonstrate how diffusion
works in an easy and quantifiable way.

"We wanted to develop an experiment for high school and college STEM
(science, technology, engineering, and math) students to show them how diffusion works in a simple visual manner and to ensure the experiment
was easy to do at home so kids can learn diffusion on their own,"
co-author Carson Emeigh said.

Driven by thermal energy, diffusion occurs when atoms, molecules, or other particles spread throughout a fluid (air or liquid) over time from the
highest concentration point to the lowest. Diffusion is widely studied
for myriad applications, from aircraft engines to drug development.

In their experiment, the researchers compared penetration levels of red
food dye in the whites of peeled hard-boiled eggs at three different temperatures: refrigerator temperature (40 F), room temperature (70 F),
and in a cool convection oven (140 F).

Each egg was taken out of the solution at a predetermined time (one hour,
three hours, five hours, eight hours, or 24 hours), sliced in half with
an egg slicer, and imaged. A digital camera on a tripod was placed above
the light box.

The study demonstrated that at each increasing time interval, the dye
diffused deeper into the egg white, with diffusion occurring more rapidly
at higher temperatures.

The experiment can be simplified for home or classroom by using a pot
or slow cooker instead of a convection oven, and eggs can be prepared
in advance, so students can make all the measurements at the same
time. Manual measurements of the penetration distance can replace the
imaging method. Soy sauce or marinade of students' choice could be used
instead of food dye solution, allowing students to "taste" the differences
in diffusion.


========================================================================== Story Source: Materials provided by American_Institute_of_Physics. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Carson Emeigh, Hyeonggeun (Luke) Bak, Dilziba Kizghin, Haipeng
Zhang,
Sangjin Ryu. Marinated eggs: An engaging quantitative demonstration
of diffusion. American Journal of Physics, 2022; 90 (4): 317 DOI:
10.1119/ 5.0062178 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220323114504.htm

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