Natural Definition and 1000 Threads

Have you ever stared into nothingness, and seen a reflection?-Me

Firstly, i am 13 years old and ive been assigned a student SRP(student research project) in my science class. Basically ill have to reasearc this topic:"Natural Light verse Artificial Light on plant growth" and write my own prac(experiment up ie Aim, Method, Material....)What im having trouble...

Is there a difference? I heard that synthetic vitamins go right though your system and create an expensive urine.Personally I take vitamins a few times a week, do they work, who knows.admin@physicsforums.com

Poll Question:Which terrestrial natural disaster best represents physics in action?Choices: Hurricane Tornado Earthquake Volcano Tidal wave/Tsunami Global warming/Ice age Solar storm Meteor/Comet impact

Brewzing via courses offered by universities in biology, I found something like "Law of evolution" class.I know that evolution theory is based on numerous observed facts and is well established theory, but is it already considered a natural law?Life is chemistry,chemistry is quantum...

This is a pretty good summary of Richard Rorty's perspective on how many view science, especially natural science. This was taken out of the Standford Philosophical Dictionary. I think I could have written a better, more comprehensive outline of Roty's thoughts, but it would have taken far too...

Poll Question:I am met with a rainbow of colours when I go to the grocery store. It really bothers me.. if someone would ask you to sign a petition against all these colourings, would you:~Monique~Choices: sign it! decline it.. ignore it. View Results

In this problem, I'm supposed to finddy/dxThe problem is y = ln([x]/[1 + x2])y = ln(x) - ln(1 + x2)dy/dx= (1/x) - [(1)/(1 + x2)][2x](chain rule applied)so...dy/dx= (1 - 2x)/(x[1 + x2])Did I get the right answer by the right procedure?Thanks"A true revolutionary is guided by great feelings of...

Does anyone happen to know a proof for the fact that every subset of the natural numbers is countable? It sounds easy enough, but I don't seem to be able to produce a proof without some vagueness.khkf

Can someone give me a good explanation of logs and natural logs? I have a faint understanding of them but I guess my teachers have not explained it in a way that I could comprehend."I love children...so much that I want to be a bachelor..."

Birds build nests.Termite build termite mounds.Wasps and bees build nests.Spiders build webs.Do we humans have an instinctive ability to come together and build some type of natural structure?

The earth has a magnetic field. Is the moon inside of this magentic field. Could the core of the moon be considered a conductor? Would this not in a sense be a sort of natural perpetual motion? Think about the workings of the solar system, that is essential perpetual motion. Its a...

The fittest plants, being the most tasty to animals, would be the least likely to survive. How does this conply with survival of the fittest?Powers of Light

Say, energy conservation law?Tom claims that theories of physics are concotted to fit observations. What do you think, is Emmy Noether theorem concoted to fit energy conservation law, or it is just logical if ...(time is symmetric, for example) then... (energy conserves as a mathematical...

In a tornado there is a concentration of kinetic energy.The same happens in whirlpools.Are there any other examples of this phenomenon in nature with electric or magnet fields or matter being the medium of the vortex which we could use for our advantage in e.g. electric power generation?

Are there any botanists out there?Has anyone out there found good internet sites devoted to plant natural history information? I am finding mostly just checklists - not details on life history

The question is:It takes 5 Newtons of force to hold the end of a spring 2 meters from its resting position. Find the work required to stretch this spring 2 meters beyond its natural length.Okay, since it takes 5 Newtons to hold a spring 2 meters from its resting position, I can calculate that...

I'm doing a research project on the Fibonacci numbers and the Golden Ratio and I need to present some natural objects where the Fibonacci Sprial is seen. I have gathered some already but need some suggestions.Here's my list so far:Nautilus...

Just how is that possible?An orange lemonade drink without any juice,but 100% natural flavoring.. where does it come from?Why are chemists great for solving problems?They have all the solutions ;)

https://phys.org/news/2020-01-fossil-upend-basic-tenet-evolutionary.html Sandra Catania et al. Evolutionary Persistence of DNA Methylation for Millions of Years after Ancient Loss of a De Novo Methyltransferase, Cell (2020). DOI: 10.1016/j.cell.2019.12.012 Using pathogenic fungus species, the...

Hello, I'm trying to follow Wolfram to do a least square fitting. There are multiple summations in the two equations to find the coefficients. Are the i's the same in this case? Thanks!

I got stuck when i eliminated the parameter.

Hey, I need some help with the following exercise, it's probably not as hard as I think but I can't really think clear right now. I would really appreciate your folks help, thanks in advance :) I wasn't sure wether to post this in the computer science or statistics category so I posted it in...

Hi, Given a mechanic-problem, I've linearised a system of two differential equations, which the origin was Lagrange-equations. The system looks like this; $$ 5r \ddot{\theta} + r \ddot{\phi} + 4g \theta = 0´ \\ 3r \ddot{\theta} + 2r \ddot{\phi} + 3g \phi = 0 $$ $$ $$ And I shall find the...

I'm only really just learning how natural units work so forgive me if this seems like a silly question. I was just wondering if someone could verify whether the following line of reasoning is valid (I will use joules instead of electron volts just so we can ignore the e conversion factor for...

Is there any phenomenon in nature that resembles or is analogous to nuclear fission?

PS: This is not an assignment, this is more of a brain exercise. I intend to apply a general derivative boundary condition f(x,y). While I know that the boxed formulation is correct, I have no idea how to acquire the same formulation if I come from the general natural boundary condition...

I figured out that the spring constant is inversely proportional to the natural length, but there’s still an unknown change in a quantity( most likely extension).

Given that electromagnetic waves transport energy via photons, what is the lowest and highest possible frequency of a photon and what physical phenomena do these relate to? It is clear that the larger the wavelength the lower the energy for a photon. so what are the limits of the wavelength?

Hi there. I am reading a paper and got stumped by a question: Why are traditional natural products considered safe over conventional chemotherapy drugs? "Chemotherapy is very important in cancer treatment but most of the drugs which are currently used in chemotherapy have lesser potential...

Zero is an integer. An integer is defined as all positive and negative whole numbers and zero. Zero is also a whole number, a rational number and a real number, but it is not typically considered a natural number, nor is it an irrational number. Why is 0 not a natural or counting number?

Let Z = set of real numbers Determine if (27/4)/(6.75) is a whole number, natural number, integer, rational or irrational. I will divide as step 1. 27/4 = 6.75 So, 6.75 divided by 6.75 = 1. Step 2, define 1. The number 1 is whole or natural. It is also an integer and definitely a rational...

This is a question arising from the discussion in another thread. It's my understanding that among systems of natural units, the Planck units system sets not only "all three of those to 1", but also does the same with the Coulomb and Boltzmann constants, leaving the elementary charge not...

Hi, I'd like to be clarified regarding the general natural/Neumann boundary condition for a PDE. 1. The natural boundary condition is generally defined as: (1) and can be expressed as, according to this resource: (2) But apparently, according to...

Leavitt's Law allows us to determine how far stars are from us by calculating their variable magnitude of brightness. Please explain how it's possible then for us to see, with the 'natural eye', the distances from one star to another, from one point in the night sky to the opposite, that would...

What is the natural $y$ from $144+{{144}^{49}}+{{144}^{{{49}^{2}}}}+{{144}^{{{49}^{3}}}}+...+{{144}^{{{49}^{2018}}}}=3({{y}^{4038}}-1)$?

Homework Statement The suspension of a modified baby bouncer is modeled by a model spring AP with stiffness k1 and a model damper BP with damping coefficient r. The seat is tethered to the ground, and this tether is modeled by a second model spring PC with stiffness k2. The bouncer is...

Homework Statement Prove that if a set A of natural numbers contains n_0 and contains k+1 whenever it contains k, then A contains all natural numbers ≥ n_0Homework EquationsThe Attempt at a Solution I'm just confused by the question, please don't answer it. Logically it makes sense that if n_0...

I am trying to anallytically determine natural frequencies ƒ of the tympanic membrane. I am using 2D sectorial annulus membrane as a simplified model of tympanic membrane according to following picture The parameters that i want to use are following: THICKNESS = 0,1 mm The natural...

It's a truism that those that are better at surviving/adapting will be better at surviving. How is that in any way enlightening or new? Is there a deeper, more complex aspect to this theory that somehow escaped me? Were there people before this theory believing that those that are worse at...

Let's say you have an impulse of noise, eg. via a guitar string, or a resonant bandpass filter, and it decays naturally. If "1" is the maximum initial amplitude of sound, and "0" is no sound at all, what is the equation for decay of sound over time (x)? Is it: y = 1/c^x Or y = 1/(x+1)^c I...

Homework Statement Calculate the natural circular frequency ωn of the system shown in the figure. The mass and friction of the pulleys are negligible. The diagram is attached. Homework Equations ωn = (k/m)1/2 The Attempt at a Solution I can see the total mass of the system is 3m. So in the...

Hello I am designing a shaft and it will be powered via belt pulley system. The ideal RPM of the shaft is 8000 RPM. How do I calculate the natural frequency of the timing belt to ensure resonance is never met? From what I read online it has to do with belt pretension, but even then I am little...

Homework Statement Find the number of natural numbers n such that (n2-900)/ (n-100) is an integer.Homework EquationsThe Attempt at a Solution I have done the following: (n2-900-9100+9100)/ (n-100) or,{ (n2 - (100)2) + 9100 }/ (n-100) or, (n+100) + (9100)/(n-100) I hope you can understand this...

Homework Statement Prove that ##\forall n \in \mathbb{N}## $$\frac{n}{2} < 1 + \frac{1}{2} + \frac{1}{3} + \ldots + \frac{1}{2^n - 1} \leq n \text{ .}$$ Homework Equations Peano axioms and field axioms for real numbers. The Attempt at a Solution Okay so my first assumption was that this part...

I just asked a similar question, but I got help for that one, and now I am stumped again. I need to find the domain for f(x) = ln(x^2-5x) What's confusing me is how to deal with the exponent. I can't think of a way to get around it.

Generally speaking, would it be better to pair a CS/Math minor/minor or minor/major (respectively) with physics or an additional natural science major (e.g., biochem, biophysics, chemistry) with physics? I plan on going to grad school to either pursue a physics Ph.D. or a master's in...

This thread is about the process of theory completion in the practice of theoretical physics, and therefore mostly directed towards practicing theoretical and mathematical physicists, but others can chime in as well. a) What exactly constitutes a natural completion of a physical theory? b) Is...

How is it that when using "natural" units we drop the units themselves. I understand that you can arbitrarily change the magnitude of a parameter by choosing a new unit. For example Oliver R. Smoot is exactly 1 smoot tall. However, in natural units with [c]=[h/(2π)]=1 the "smoot" part is...

In the past, natural selection selected those who are the fittest to live to pass their genes, and eliminated those who are not, but now most people pass their genes, even those who don't have the best genes to live, although now not having the best genes may affect the qualify of a person's...