Interview is in 30 minutes.
I’ll tackle your question in two parts.
Nano: Yes. Anything 100 nm or less in any dimension is considered nanoscale. So if we imagine your box is 100 nm x 100 nm x 100 nm. My job depends on being able to pass current through objects this size without melting them so I can tell you that you can. Of course, you have to be careful. Keep your currents small (in the micro Amp range) so as not to overheat/blow-up your samples.
Pico: Let’s talk about pico. A picometer is a trillionth of a meter. It’s a thousandth of a nanometer. The smallest atom (Helium) is 32 picometers in diameter. So a picoscale box is going to be an atom or at most a single molecule. Interestingly, scientists have passed a current through a single molecule with success. In an STM they passed a few nano amps through a single molecule and got it to behave like a transistor.
Source (x) Kai Sotthewes, et al. APL MATERIALS 2, 010701 (2014)
Thanks. We’re glad that you’re glad. DFTBA.
To give a full answer this we could actually go into a lot of fundamental physics, so I’m going to try to keep it simple, while still answering the question and give you all some buzzwords that you can look into in greater detail in your own time if you’re really interested. The buzzwords will be in bold; just bang em into google to go deeper.
So the colour/temperature link really has to do with Black Body Radiation. As the temperature of a body increases, the energy emitted from it increases in frequency and decreases in wavelength from the infra-red (long) to the ultra-violet (short) passing through red, orange, yellow, white, and blue along the way.
We’ll talk specifically about a flame. I’m not so familiar with blow torches so I’ll talk in terms of Bunsen burners. They should be similar. So when you light the low oxygen flame on the Bunsen it is yellow (fading to red at the top like a fireplace fire) and burns at ~ 1000 C. Due to the lack of oxygen in the combustion process the process is incomplete and a lot of soot is left over from the fuel burning. These very fine soot particles burn up in the yellow flame and Black Body radiate. Increasing the oxygen flow allows for more combustion to occur and you transition gradually to the clean flame which burns blue and has no soot left over from the fuel. So the blue colour comes, not from soot, but from the ionization of gas molecules by the energy of the flame. These ions emit light at ~565 nm which is in the blue/green area of the spectrum.
The colour changes are a mixture of black body radiation and ionization of gas molecules at high temperatures. More oxygen allows for more combustion of fuel and therefore a hotter and cleaner flame.
A candle burning from hottest (blue at the base) to coolest (red at the tip)
Hey, continue to be interested in the world and find out as much as you can from the internet/public lectures/people around you. Then you are a scientist. Everything else is just letters on a degree.
I have a really important interview today re: my PhD continuing for the next two years. So today is going to be Answering The Inbox day because I have nothing else planned and I think Adam might be in Greece??
It’s a mix of question answering and just straight-up-unapologetic fan mail. No regrets.
Newton’s third law says that forces come in equal and opposite pairs. This means that when air exerts lift on an airplane, the airplane also exerts a downward force on the air. This is clear in the image above, which shows a an A380 prototype launched through a wall of smoke. When the model passes, air is pushed downward. The finite size of the wings also generates dramatic wingtip vortices. The high pressure air on the underside of the wings tries to slip around the wingtip to the upper surface, where the local pressure is low. This generates the spiraling vortices, which can be a significant hazard to other nearby aircraft. They are also detrimental to the airplane’s lift because they reduce the downwash of air. Most commercial aircraft today mitigate these effects using winglets which weaken the vortices’ effects. (Image credit: Nat. Geo./BBC2)
Minimalist Poster Series Honors Science’s Women PioneersMinimalist Poster Series Honors Science’s Women Pioneers
On this day In 1961, cosmonaut Yuri Gagarin became the first ambassador of our planet to enter the vastness of space. Vostok 1 was the first manned spaceflight of the early space race, and Gagarin completed one orbit of Earth before landing safely 108 minutes later.
While flying weightless above Earth’s surface, Yuri Gagarin witnessed a spectacular view of home — forests, deserts, and great plains were surrounded by expansive oceans. Upon viewing the thin blue line of the atmosphere, Gagarin became the first of our inquisitive species to see our planet as it truly is — a vibrant, geologically active world circling a star. We at Penny4NASA urge you to honor the memory of this brave man, as his Vostok 1 mission was the catalyst for every manned spaceflight adventure to date.
Remember and honor this great (hu)man by exploring all of my related posts on Yuri Gagarin. Ad astra per aspera*