🎓 Doc Freemo 🇳🇱 @freemo@qoto.org

This is a picture of the first moments of a nuclear explosion taken in 1952. The blast radius at this moment is less than 20 meters wide.

There are so many extraordinary things about this photo. First off the fact that they had a camera in the 1950's capable of such insanely high speed frame rates (they created a movie from this) that it was capable of 1,000,000 frames per second. In many ways that is more impressive than the nuclear bomb itself.

Second the fact that you can see, in real time, a nuclear explosion as it happens. Those spikes at the bottom are called the "rope trick effect" which is caused by the support cables inside or holding up the bomb. The light radiation is so intense it vaporizes anything nearby causing things to explode just from the intensity of the light itself (before radiation has any effect at all). So those spikes are literally just the support cables exploding in the extraordinarily bright light from the bomb.

#Science #STEM #Physics #History @Science

Interesting fact of the day: The same effect that cuased light in a prism to split up into different colors is what ultimately caused the first transatlantic telegraphic wire in 1858 to fail.

Morse code is transmitted as on-off signals, effectively square waves. Square waves are in fact made up of many different frequencies. Like in a prism different frequencies move at different speeds through a wire. Therefore as the on-off pulses traveled through the transatlantic telegraph wire the signal spread out like it does in a prism and ultimately the pulses would overlap and be indistinguishable.

The effect was so extreme that it took a message of only 98 words (the first message sent) over 67 minutes to send one way and a whopping 16 hours to confirm the message.

Whitehouse, a doctor with little mathematical understanding, thought he could solve the problem by increasing voltage, which we now know was a futile effort. He increased the voltage to the point he managed to short out the cable entirely and made it useless. However Lord Kelvin had already warned of the problem as was ignored and he came up with the law of squares to describe the problem which later was refined to give us the telegraphers equation. The telegraphers equation is still used today to model feedlines in radio transmitters and receivers.

#Science #STEM #Physics #History @Science #QOTOJournal

Anyone out there other than me old enough to have run a 10base2 network in their home? My first computers 2 computers when I was in high school I connected together with a 10base2 with 50 ohm terminators and all that. My mom wasnt happy as I literally knocked a hole in her wall without asking her.

This was back when the internet was still fairly new so you would get on with 1200 baud modems to a BBS that would give you a piggyback onto the internet which you might be lucky to get access to for 30 - 60 minutes a day.

10base2 network card attached for prosperity.

#History #Computers #CS #Engineering #ComputerEngineering #ComputerScience #Science @Science

Ya know those tiny network routers you have on your desk that you use to connect all your computers together and connect to the internet... Well this is what it looked like in the early days when the internet didnt exist as a word yet (It was still called ARPANet). Like most computer devices from the 70's it would take up a nice chunk of the room.

#History #Computers #CS #Engineering #ComputerEngineering #ComputerScience #Science @Science

A map of every node on the internet (ARPANet) in 1974, which was exactly 3 years after the network first went live.

#History #Computers #CS #Engineering #ComputerEngineering #ComputerScience #Science @Science

Damn you newton!

#Isaacnewton #newton #history #physics #STEM #Science @Science @funny #funny #joke #humour #humor

So a while back i realized you can create an extremely high energy hot plasma in the microwave consistently by taking a coil and streching it out and forming it into a loop with one gap on the sad. The ark that forms has huge amount of energy in a very small space. In the past it has melted a blob of borisilicate glass almost instantly fuzing the coil i to the glass under neath.

It has a tendency to grow into a large cloud of blasma that rises to the top of the microwave usually. Since this ball plasma is much larger the energy is spread out. Despite still being extremely hot its nowhere near the heat of the initial ark as it takes some time to heat glass to its melting point in this state.

So i had an idea. What would happen if i contained the arc under a pile of salt, in this case potassium salt. It should keep the plasma contained and due to maintaining a very small volume should retain the enormous heat i figured it would be more than hot enough to melt the salt but i wanted to try it out.

Attached is the video in the microwave itself. I will reply to this thread with various stills before and after of the setup showing the final results

#chemistry #physics #science #STEM @Science

Seems we have an X-class flare hitting us this weekend. Batten down the hatches boys.

#RF #Radio #Science #SolarWeather #STEM @Science

"Math is never just numbers, when words fail us we use math to describe the inexpressible, the things that terrify us most: the vastness of space, the shape of time, the weight and worth of a human soul." - Foundations

#math #quote #Foundations #Science #stem #philosophy @Science

"Math is never just numbers, in the wrong hands it is a weapon, in the right hands it is deliverance" -- Foundations

#Math #Science #STEM #Philosophy @Science

This is what it looks like when you take cyanoacrylate and sone accelerator, through it in a pill capsule, shake them together and watch the reaction quickly harden. It gets so hard it starts smoking.

#science #chemistry #stem @Science

Interesting fact of the day. The very first internet connection consisting of 3 interconnected nodes was in fact WiFi... well, not wifi but radio/wireless. It was implemented as a mobile ad-hoc access point equipped in a van with the first 3-way network occurring in 1977.

#history #technology #STEM #Science @Science

Interesting fact of the day: A chimpanzee is about 1.3x to 1.5x stronger than humans when it comes to pulling, jumping, and lifting with the legs in general. However when it comes to physical strength in terms of **pushing** humans are significantly stronger than chimps. Similarly while our legs arent as strong in terms of explosive power (jumping) we are many times better at endurance (using our leg muscles for longer). A human can cover a much farther distance on foot than a chimp could.

So the general factoids about chimps being stronger then us are very misleading. They are simply adapted to be stronger at the sorts of tasks they are suited for and weaker in others, while humans are stronger than a chimp in other ways.

#Science #STEM #Biology #zoology #monkey #chimp #ape #chimpanzee @Science

A friend of mine asked me why DNA and RNA are acids. I am **not** an expert in chemistry but I did study the basics of organic chem and do dabble a bit so I wanted to share the answer here.

Simple answer: Anything that lowers pH is an acid, RNA and DNA lower pH, therefore it is an acid.

Complex answer:

Nucleic Acids are called acids because, well, they lower pH, as anything that is an acid would. pH is, in simplistic terms, the concentration (logarithmicly) of H+ ions in a solution.

A unrelated side note with acids that dont directly donate a H+, your Lewis Acids, they still increase H+ in an aqueous solution because it effects the balance of H+ and OH- dissociation of the water itself. As such the H+ measure is still accurate. However Nucleic acids are not a Lewis Acid, they are a Bronstead-Lowry acid, which means they directly can dissociate and provide the H+ ion directly in an aqueous solution. But I'll get to that.

The individual parts of any molecule can be either acidic and basic, but a molecule overall will usually be one or the other depending on which dominates, RNA is no different, there are three major components to RNA, I attached a picture to show them. The components are a phosphate group, a sugar, and a nitrogenous base (the part that encodes data, your citosine and guanine and shit). Here is the cool part, the word base when talking about the "bases" of a strand is specifically chosen as the the word because they are themselves bases (on their own they would raise pH). Similarly the phosphor group, is also acidic, this should be obvious by its similarity to phosphoric acid. It is a proton donor for the same reason phosphoric acid is a proton donor.

So the only question remaining is why does the acidic phosphor group dominate over the Nitrogenous Base? Well for starters the the phosphate group has a pkA of near 0 , the Nitrogenous Base has a pkB of around 9.8 (depends on the base), so already the phosphate group is going to dissociate more readily than the Nitrogenous Group. However RNA strands are actually far more acidic than the individual Nucleotides that compose them happen to be. The reason for this is that RNA folds back in on itself with the bases associating with each other much like two halves of a DNA strand would. This causes the bases to be on the interior of the molecule while leaving the phosphate groups all around the outside. Since the bases are not exposed to the aqueous solution they do not dissociate as readily as they otherwise would while the phosphate groups are free to dissociate. Thus the RNA exhibits significant acidic properties.

By the way the acidic nature of RNA and DNA is intentional and functionally important. It means that the pH of the solution can be adjusted to effect the charge on the nucleotides and thus move it around. In a neutral pH solution the phosphate groups will have a negative charge. This results in the phosphates pushing each other away. This in turn can cause them to line up on opposite sides with their bases facing each other as well as help to straighten out a strand's backbone.

#DNA #RNA #Chemistry #Organic Chem #OChem #OrganicChemistry #Science #STEM @Science

As a free speech instance this is all to relevant. Science can not exist without it.

"A dictatorship means muzzles all round and consequently stultification. Science can flourish only in an atmosphere of free speech." - Einstein

#FreeSpeech #Einstein #Quote #Science #STEM

Einsteins true genius was in seeing past the accepted truths to a more fundamental nature of the universe than our preconceived notions would allow:

"Concepts that have proven useful in ordering things easily achieve such authority over us that we forget their earthly origins and accept them as unalterable givens. Thus they might come to be stamped as "necessities of thought," "a priori givens," etc. The path of scientific progress is often made impassable for a long time by such errors. Therefore it is by no means an idle game if we become practiced in analyzing long-held commonplace concepts and showing the circumstances on which their justification and usefulness depend, and how they have grown up, individually, out of the givens of experience. Thus their excessive authority will be broken. They will be removed if they cannot be properly legitimated, corrected if their correlation with given things be far too superfluous, or replaced if a new system can be established that we prefer for whatever reason." -- Einstein

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Original:

Begriffe, welche sich bei der Ordnung der Dinge als nützlich erwiesen haben, erlangen über uns leicht eine solche Autorität, dass wir ihres irdischen Ursprungs vergessen und sie als unabänderliche Gegebenheiten hinnehmen. Der Weg des wissenschaftlichen Fortschritts wird durch solche Irrtümer oft für längere Zeit ungangbar gemacht. -- Einstein

#Stem #Science #Einstein #Quotes @Science

Hacked together an ultraportable HF antenna system to work well between 3.5Mhz - 200 MHz (80 meters - 2m) frequencies. Basically took a coil loaded GRA-1899T antenna with telescoping antenna, added some off-the shelf BNC adapters and did some minor hacking. To make it work I had to remove the center connector from two of the BNC adapter s(marked with an X in the diagram). Then added a short-circuit BNC connector, which connects the otherwise floating center connector from the bottom half to ground/shield enabling the counterpoise. Added two additional telescoping elements for the counterpoise and we have a complete system.

The thing I like about the approach is the modularity. For example I can remove or add normal t-connectors to change the number of counterpoises used. The setup pictured uses 2 counterpoises but it would be trivial to setup 1 to 4.

Also the short circuit connector (pictures here as the black and teal connector with the short circuit in it) can allow me to do multiple things if i want to get more complicated. For example if I want to remove the short circuit I can replace it with coils or capacitors for additional tuning. I can also leave it as is but connect an earth ground to it to improve the effectiveness of the counterpoise.

A final note, the loading coil attached to the radiating part of the antenna has a jumper with 6 different positions. This lets you manually adjust the size of the loading coil for different frequencies. Fine tuning is accomplished by changing the length of the antenna itself.

#Science #electronics #RF #radio #Amateur AmateurRadio #HAM #HAMRadio ## @Science

cool article about creating matter from light:

https://www.bnl.gov/newsroom/news.php?a=119023
"
#science #physics @Science

I am really digging the back and forth video science debate regarding the chain fountain ElectroBoom and Steve Mould are doing.

This is the 4th video, each of them are 2 videos in at this point.

https://youtu.be/0xr8Vh7z83g

@Science #science #physics

You know you are a nerd when you by a textbook for over a hundred dollars and at twice the price just to get it new and then cant sleep the night before because your excited to get it....

@Science #science #physics #math #maths #mathematics #EE #electronics