A 50-kilogram anvil floats perfectly on the surface of mercury, because the density of the steel from which it is made is almost half the density of mercury.
Fun fact! Many lighthouses with especially large fresnel lenses would have huge fucking tubs of liquid mercury in the lantern room because it’s a super easy way to make these giant lenses rotate quickly!
Shockingly, however, spending most of your time in close proximity to 500 pounds of liquid mercury is Not Great For One’s Health and tons of lighthouse keepers started to go crazy from the whole. Mercury poisoning thing. Hence why there are a lot of “haunted” lighthouses or wickies that lose it and maybe do a bit of manslaughter.
Anyway, people saw a bunch of lighthouse keepers go crazy and get sick and got empirical evidence that it was in fact related to the 500 pound mercury bath they have to visit every day and then they decided nah it’s fine actually. So we’ve kept the liquid mercury thing and I think that’s beautiful
I love how it is so dense it does not "wet" the anvil, the drops all run and leave with nothing behind them unlike water, oil, sauce... it's super satisfying it's like in cartoons
In a letter written on April 19, 1825, Augustin Fresnel proposed the use of mercury to reduce the friction in revolving lenses. His statement follows: “I propose to float our rotating devices, of the first order, in a bath of mercury, instead of placing them on rollers. This project won't present many difficulties; nevertheless, as I have not put it into execution, I won't require you to adopt it for your first lighthouse.”
Fresnel’s plan for mercury flotation was not put into practice until 1890 when Monsieur Leon Bourdelles, Chief Engineer of the French Lighthouse Service, designed and built a workable mercury flotation system. The mercury bath allowed the lens to operate in an almost frictionless environment and, additionally, allowed the speed of rotation to be dramatically increased.
Lens Rotation by Thomas Tag | United States Lighthouse Society
Under less-than-ideal conditions, you can only see the beam when it’s pointed more or less directly at you. In-between beams you would not be able to see anything. One solution to this was to create multiple beams, and the lenses Mr Fresnel designed usually created 8 beams. But, even still, duration between flashes could be as long as one minute in the old mechanical roller systems.
The nearly frictionless operation of the Mercury suspension system allowed the lenses (large pieces of precisely ground glass weighing several hundred pounds in some cases) to rotate fast enough that they could be redesigned to create fewer (usually 3) beams. Fewer beams from a similar light source will be proportionally brighter, and the gains in speed were sufficient that duration between flashes could still be reduced to as little as 10 seconds.
This was a big upgrade. It didn’t just make the lighthouse signal faster, it allowed them to completely overhaul the lens and derive more visibility from a light source.
1) Vaping is confirmed to cause cancer. Vaping coats the lungs with toxic substances, such as heavy metals and benzene, which are known to cause cancer
2) Many vapes contain diacetyl, which, when inhaled causes popcorn lung, or scarring of the lung
3) Ultrafine particles, when being inhaled, can be lodged in the trachea (not good!)
4) Ultrafine particles can also constrict the arteries in the lungs potentially causing A HEART ATTACK
5) Vaping is relatively new. Not much studies have been done in comparison to tobacco. Plus, the vaping companies are powerful people. There is a large chance that they are purposely downplaying and even burying any evidence that vaping is harmful - just like the tobacco companies before them. They do not care about you, or your health, or the truth. They only care for money
Please I’m begging yall as an asthmatic, your fruit-flavored vapor will still give people around you who are smoke-sensitive attacks. So will weed. Don’t do it inside; if you’re at a bus stop or something try to not stand right next to people or move downwind of them if you can.
Decades-long campaign powered by patient perspectives results in switch from PCOS – a name that caused confusion and undue suffering – to PM
a health policy paper has been published saying the name is officially updated to polyendocrine metabolic ovarian syndrome (PMOS)
polyendocrine= multiple endocrine factors
metabolic = affecting/affected by metabolism
ovarian = from the ovaries
essentially, instead of using the symptomatic term (many people with PMOS do not develop cysts) the new term widens the diagnostic area and makes it easier to diagnose, treat, and do research on people with PMOS (even atypical types, such as no cysts).
it may seem like a waste of time to change a name instead of focusing on research, but for a lot of medical professionals a name can be associated with a hard set collection of symptoms, so the name needs to change to acknowledge that the disorder is not well understood and has a broader, subtler, and often missed set of symptoms. for example ADD is considered an antiquated/unused term, and now comes under the ADHD umbrella. in healthcare names and terminology changes all the time, and this is a positive change. your local healthcare professional may not know about this unless theyre really up on the news though!
in case you want to read about the name change process that was published in the Lancet (one of the most impactful and well respected medical journals):
Polyendocrine metabolic ovarian syndrome (PMOS), previously named polycystic ovary
syndrome (PCOS), affects one in eight women. However, the
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