Something that I've noticed across most of the microwave ovens that I've used is that when they hum while cooking food, I can pick out 2 distinct tones. One of them is pretty clearly ~~60~~ 120 hz, the 2nd harmonic of the AC power frequency. The other is consistently a minor 7th above that (which would be somewhere around ~~106-108~~ 212-214 hz depending on the exact ratio). What causes this 2nd frequency to be produced?

Edit: after checking against a tone generator, the low frequency is actually 120 hz, double the grid frequency. The question is still the same, just an octave higher.

Amouranth, the Kick streamer, is allegedly brewing beer with her vaginal yeast. It's an obvious publicity stunt to squeeze more money from her impressionable and "thirsty" audience.

Gross-factor aside, is this even possible? Is it analogous to brewer's yeast? Would this cause undesirable side effects or introduce undesirable compounds?

And if so, how much? Less, same or more than if it was actually charging something?

I'm in the EU if that changes something.

So, I learned in physics class at school in the UK that the value of acceleration due to gravity is a constant called g and that it was 9.81m/s^2. I knew that this value is not a true constant as it is affected by terrain and location. However I didn't know that it can be so significantly different as to be 9.776 m/s^2 in Kuala Lumpur for example. I'm wondering if a different value is told to children in school that is locally relevant for them? Or do we all use the value I learned?

I often hear science-adjacent folks stating that a tree needs to be 30 years old before it starts absorbing CO₂, usually paired with the statement that it's therefore pointless to start planting tons of trees now for slowing climate change.

Now, as far as my understanding goes, the former statement is very obviously nonsense. As soon as a tree does photosynthesis, it takes carbon out of the air, which it uses to construct cellulose, which is what wood is made of.
Really, it seems like it would absorb most CO₂ during its initial growth.

I understand that it needs to not be hacked down + burnt, for it to actually store the carbon. But that would still mean, we can plant trees now and not-hack-them-down later.

I also understand that some CO₂ invest may be necessary for actually planting the trees, but it would surprise me, if this takes 30 years to reclaim.

So, where does this number come from and is it being interpreted correctly? Or am I missing something?

Edit: People here seem to be entirely unfamiliar with the number. It might be that I've always heard it from the same person over the years (e.g. in this German video).
That person is a scientist and they definitely should know the fundamentals of trees, but it was usually an offhand comment, so maybe they oversimplified.

According to quantum field theory, the universe can be thought of not as isolated particles but continuous fluctuating fields: matter fields, whose quanta are fermions (i.e., leptons and quarks), and force fields, whose quanta are bosons (e.g., photons and gluons). All these fields have zero-point energy.>

Zero-point Energy

Is the quantum mechanical math just easier to calculate each having its own separate field, rather than an identical field of origin, but each unique excitation giving each their own identity/unique properties?

Sometimes QM systems seem true to reality and at other times just the best description we have at the moment - I find it more plausible for there to be a shared field of origin that diverges from unique excitations/properties. It's also very likely I'm studying QM fields incorrectly.

Thanks for any insight.

I’ve been trying different searches but everything I find just says “sunlight”. Since sunlight consists of multiple parts such as UV, Infrared and the normal visible spectrum, I’m curious which part is actually responsible for photosynthesis to occur? On that note, depending on what part of the light, would it still grow with an LED, black light, etc.?

There's supposedly a variety of different spectroscopy methods but what drives the choice of one method over another? If elements drive the colors, how do you parse out individual elements from a compound?

Is there a consistent pattern to how the emission lines relate to what the element looks like before going through the prism? Is there a resource that shows examples of emission lines along with the visible color?

My initial thought is "no," since our eyes, being receivers for specific wavelengths of EM radiation, can't see frequencies like infrared, no matter how bright. Likewise, my cell phone's WiFi and cell modules don't conflict with each other (as far as this layperson can tell, anyway).

But if, for example, infrared were sufficiently bright/energetic, could it affect neighboring frequencies, like reds?

In nuclear chemistry elements beyond Plutonium do not occur in nature and are synthesized artificially. Is it a similar case for Higgs boson too?

If so, how does it give mass to particles if it doesn't exist? Did scientists create Higgs at LHC in 2011 just to make sure our universe exists through some kind of circular causation?

I'm obviously not understanding this properly. Please dispel my misunderstandings with reasonable explanations!

I felt a strange urge to buy me some bugs and let them eat my plastic garbage after watching this video 😂

Someone commented that microplastics would still emerge during/after bugs have dealt with plastics.
Do we have any bug existing that could eliminate microplastics as well?

Seeing as the heat death of the universe occurs once black holes have stopped emitting Hawking radiation, and BH's life spans are tied to their mass, could a (very, very advanced) civilisation bring two or more together? Assuming nobody's succumbed to proton decay before then, of course.

Bonus question: if so, what's the longest timeline we could theoretically make? I'm thinking it would involve a black hole using all the matter in our local galaxy cluster.

On their massive scale you’d think that several would have opposing arms different lengths due to the way suns and solar systems end up forming. Most of the imagery I see shows almost all galaxies symmetrical. Just curious.

Wouldn't grow something from the inside require a very strong force to "move" the already present one? Instead growing from the last "layer" towards the outside would require a lot less force, but perhaps a lot more matter.

Is it even correct that trees grow concentrically?

Now that I think about it, how do plants grow in general? Hahaha

Update: for everyone wondering, yes, my question doesn't make sense because the i.e. contradicts the question. I don't want to correct it because I don't know which part to correct since I was wrong, I thought trees grew new parts inside and pushed older parts outside. So I could correct the i.e. and swap "innemost" with "outermost" but that would mean that people would read a question stating something that is wrong, or I could correct the question and swap "inside" with "outside" but I was wrong and I'm glad I learnt something today. We can all agree that I asked a weird question in a weird way, thank you all for your answers.

Could we, in theory, use something like CRISPR to give a new baby replacement super-kidneys (or whatever organ it is that makes drinking saltwater be a bad time)? It seems like if we cracked that, we'd be set as a species.

Thanks for your time.

I picked up a low pressure sodium lamp and am working on a Halloween demonstration. I’m hoping to make a display that appears one way under normal light, but looks totally different under the monochromatic 589nm sodium vapor light.

So basically, I’m looking to generate a color wheel where I pick a shade of gray and get a list of colors that would look that gray under sodium vapor light.

…I feel like there must be a Python library for thing or something…

... or do they just make up for it with sheer unrelieved quantity of greenery, perhaps?

Does anyone have a list of long-term effects that may arise from periods of severe dehydration in childhood, particularly how this might affect overall health in adulthood?

"Stronger" hearts typically have a resting pump rate lower than that of weaker or less healthy ones. A healthy, athletic male might have a resting BPM of 60, while an otherwise healthy but post-partem female could be closer to 90.

Would both of these hearts expend the same energy pumping 120 BPM? Would the healthier heart be theoretically expending more as it is acting in double-time, or would the weaker one be working harder as it is already inefficient at pumping blood?

Seems like it should and the result should be one. Does mathematics agree with me on that?