Biology experiments are hard, and so they go wrong, a lot.
For this reason, it is wise to verify that certain steps are correct whenever possible.
And so this is the first thing we did on the second day!
Gel electrophoresis separates molecules by their charge-to-mass ratio. It is one of those ultra common lab procedures!
This allows us to determine how long are the DNA fragments present in our solution.
Since we know that we amplified the 16S regions which we know the rough size of (there might be a bit of variability across species, but not that much), we were expecting to see a big band at that size.
And that is exactly what we saw!
First we had to prepare the gel, put the gel comb, and pipette the samples into wells present in the gel:
Figure 1.
Gel electrophoresis insert comb.
Source.
Figure 2.
Gel electrophoresis top view with wells visible.
Source.
Figure 3.
Gel electrophoresis pipette sample into wells.
Source.
To see the DNA, we added ethidium bromide to the samples, which is a substance that that both binds to DNA and is fluorescent.
Because it interacts heavily with DNA, ethidium bromide is a mutagen, and the biology people sure did treat the dedicated electrophoresis bench area with respect! Figure 4. "Gel electrophoresis dedicated bench area to prevent ethidium bromide contamination.".
Figure 4.
Gel electrophoresis dedicated bench area to prevent ethidium bromide contamination.
Source.
Figure 5.
Gel electrophoresis dedicated waste bin for centrifuge tubes and pipette tips contaminated with ethidium bromide.
Source.
The UV transilluminator we used to shoot UV light into the gel was the Fisher Scientific UVP LM-26E Benchtop 2UV Transilluminator. The fluorescent substance then emitted a light we can see.
As barely seen at Figure 8. "Fischer Scientific UVP LM-26E Benchtop 2UV Transilluminator illuminated gel." due to bad photo quality due to lack of light, there is one strong green line, which compared to the ladder matches our expected 16S length. What we saw it with the naked eyes was very clear however.
Figure 6.
Fischer Scientific UVP LM-26E Benchtop 2UV Transilluminator
. Source.
Figure 7.
Fischer Scientific UVP LM-26E Benchtop 2UV Transilluminator loading gel.
Source.
Figure 8.
Fischer Scientific UVP LM-26E Benchtop 2UV Transilluminator illuminated gel.
Source.
Charles K. Kao by Ciro Santilli 40 Updated 2025-07-16
Figure 2.
2009 Nobel Prize lecture
. Poor Charles was too debilitated by Alzheimer's disease to give the talk himself! But if you've got a pulse, you can get the prize, so all good.
Radio wave by Ciro Santilli 40 Updated 2025-07-16
This is likely the easiest one to produce as the frequencies are lower, which is why it was discovered first. TODO original setup.
Also because it is transparent to brick and glass, (though not metal) it becomes good for telecommunication.
Some notable subranges:
Microwave source by Ciro Santilli 40 Updated 2025-07-16
Microwave only found applications into the 1940s and 1950s, much later than radio, because good enough sources were harder to develop.
One notable development was the cavity magnetron in 1940, which was the basis for the original radar systems of World War II.
Cavity magnetron by Ciro Santilli 40 Updated 2025-07-16
Apparently, DC current comes in, and microwaves come out.
TODO: sample power efficiently of this conversion and output spectrum of this conversion on some cheap device we can buy today.
Video 1.
Magnetron, How does it work? by Lesics (2020)
Source.
Video 2.
Device that Won WW2 by Curious Droid
. Source.
The Suruga Trough is a deep-sea trench located off the coast of Shizuoka Prefecture in Japan. It is part of the Nankai Trough system and runs parallel to the Izu Peninsula. The trench reaches depths of approximately 2,500 meters (about 8,200 feet) and is primarily significant for geological and geophysical studies.
K. B. Reid is an author known for writing in the genres of romance and young adult fiction. One of her notable works is "The Love Hypothesis," a popular book that blends elements of romance with themes of personal growth and emotional exploration. Reid's writing often features relatable characters and engaging plots, which resonate with a wide audience.
"Radio 1's Live Lounge – Volume 2" is a compilation album released by BBC Radio 1, featuring various artists performing live covers and original songs. This series showcases popular musicians and bands as they put their unique spin on notable tracks, often blending genres and styles. The Live Lounge sessions are well-known for their intimate setting and the creative reinterpretations of songs.
The Internet Society (ISOC) is a global nonprofit organization founded in 1992. It aims to promote the open development, evolution, and use of the Internet for the benefit of all people throughout the world. The organization is composed of a diverse community of individuals, including: 1. **Members**: ISOC has individual and organizational members who support its mission and participate in its activities. Membership includes people from various backgrounds, including technologists, policymakers, educators, and internet enthusiasts.
In association football (soccer), a squad number is a unique number assigned to a player within a team for a particular season or competition. Each player on a team typically dons a specific number on their jersey, which not only helps identify them on the field but also holds significance in terms of tradition and player roles.

Pinned article: Introduction to the OurBigBook Project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 2.
    You can publish local OurBigBook lightweight markup files to either https://OurBigBook.com or as a static website
    .
    Figure 3.
    Visual Studio Code extension installation
    .
    Figure 4.
    Visual Studio Code extension tree navigation
    .
    Figure 5.
    Web editor
    . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
    Video 4.
    OurBigBook Visual Studio Code extension editing and navigation demo
    . Source.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact