This graph is analogical to movement in the universe. It is in fact the graph of the reciprocal of the hyperbolic tan function. What I wanted to demonstrate was the seemingly impossible nature of the graph switching from a value of infinity to negative infinity across the line x=0. I think that when we do discover the exact nature of space in the universe it will be dependent on a curved model in so that the three dimensional plane of space will fold back in on itself, metaphorically speaking, like a sphere so that anyone attempting to reach the edge of the universe will find it is in fact impossible.
Watching this video by VSauce recently, reminded me of a question that I had once asked myself: do we all see colours in the same way? When Michael mentioned Tommy Edison in the video, I was absolutely dumbfounded, since a mere month ago I had visited his channel and gone through the same thought process mentioned in the video. If colours are in fact merely relative illusions which require you to actually be somebody to experience, then is everything else different for everyone else, and is our perception of reality blinding us to others' perceptions? Who is to say that the things we touch, feel, see and generally experience through our senses are experienced in a similar way by anybody else? In fact, if everything you think about in life depends on your 'view' on it (assuming your 'view' has been shaped by the experiences you have gone through since you were born) then must the physical senses also by that conclusion be subjective - were they shaped by what happened to you while developing from one lowly cell into a fully functional organism?
Anyway, watching the video highlighted something I had never really considered in depth before: the theory of mind. In the video, Michael mentions a case study where a child is told that a woman called Sally puts an apple in a box, inside a room with a box and a crate, and then leaves the room. Then another woman called Susie comes into the room and takes the apple from the box and puts it in the crate. When the child is asked where Susie would look for the apple if she came back into the room, the child says the crate - although it has been made clear that Susie was not in the room when the apple was moved and therefore would not know that the apple had been moved through simple logic.
VSauce's Michael suggests that this is due to children not being able to perceive that others might have different perceptions of reality to ourselves, and that everybody sees everything in the same way. He even suggests that although we can hypothesise about animals not seeing the world in the same way as us, they cannot do the same with regards to us perhaps. Whether this is due to their having different brain structures to ourselves or due to them being able to experience the world using different - or slightly-altered versions of, - senses to ourselves (for example a butterfly being able to see the UV-section of the spectrum) we do not know.
In fact, perhaps (and this is just my opinion) it could be that children are born into this world with an all-knowingness that results from the essence of their souls - their very being itself. Before we are born (that whole topic is something best left for another post (or book)) it might be that we can simply experience every sense, even the ones that we might not think exist, and that due to this overwhelming all-knowingness we have none of the prejudices created through ignorance. Perhaps it is true that total ignorance is bliss, but some ignorance creates relativity. So, if you knew nothing about what this universe actually was, you wouldn't exist in any sense (until somebody conceived that person who knew absolutely zero in a thought or blog-post perhaps), but if you know everything through being able to experience everything through every sense possible, then you are never going to see anything relatively, since all the relative senses are also available to you and you will be able to see how they all relate to each-other: you must be omnipresent essentially. A being exhibiting such traits might be described as 'God' depending on the relative culture or faith-group you originate from. But of course, we know not everyone has the same senses - firstly because we all experience the world through different senses, secondly because the actual absence of sense is a sense within itself. Have you never wondered why as a child you were so much more creative? In fact in a test conducted, 98% of five-year olds were technically classed as creative geniuses (Genii perhaps? This word is very odd, but then spelling it as it is normally spelt enforces the concept of old Latin words becoming Anglicised through adding the ending 'es' for a plural and is therefore probably correct. That is how English originated anyway!), whereas just 2% of adults were in a similar experiment. These figures speak for themselves. Why though? Is it because society forces us to think in a certain way? Or is it perhaps because the five year olds had no tangible way to relate to the world. It has in fact been shown that the further away you are from something mentally or physically - the more creative you become in terms of describing or using it - the purest form is an abstract concept: the very definition of the intangible and the pinnacle of creativity itself. It is ironic since intangibility is in fact an abstract concept in itself. It seems to be that intangibility and abstract concepts are things which can only be described in terms of themselves: something which I will come on to later. In fact, the YouTuber Tommy Edison, who has been blind all his life is baffled by the concept of colour - however, perhaps this complete and utter confusion is part of what it takes to understand the world. People who can see can never experience what it must be like to have never know colour - since they will always have the concept clearly written into their memories. It is interesting - since it becomes a paradox to be able to understand the whole universe: you would need to be able to experience both all and none of the senses at the same time, which to the human brain is an impossible feat. Perhaps however, we only consider this an impossible feat because of the prejudices of the rules laid out for us by common 'logic'. What is to say that nothing and everything can't exist simultaneously. Isn't existence itself just another concept we talk about but never really understand?
Back to relativity and the idea of something which can only be described in terms of itself. In fact, everything we have ever known or will ever know fits this bill. You might say that this isn't true, but by definition it both is and isn't, depending on your relative standpoint.
Everything we know loops in a circle coming back to itself: the universe, logical arguments, physical concepts... the list goes on and on. They are the strange loops that Hofstadter talks about in Godel, Escher, Bach. In fact, take the concept of physical mass for example. What is it really? It is not determined by anything other than how much force needs to be applied for a set interval to make it start moving a certain distance per unit time. But of course, what is force defined in terms of? Mass and acceleration of course. Nothing else. We can only find out the mass of objects by comparing the relative properties of different objects - relative to each-other. It seems almost paradoxical, but it works - the universe itself is a paradox.
By the way, with reference to butterflies, how do they experience the colour given by the ultraviolet region of the spectrum? Is there not a clearly defined number of colours that exist - those that a healthy human can see? How can a butterfly see all those colours, and then some? How does the butterfly's brain process all those different colours. You then come to realise that, in fact, colour is merely an illusion created by our perception of reality - it is relative to the person experiencing the colour. Very much 'beauty is in the eye of the beholder'-style. In fact, as has been mentioned in physical journals millions of times - the universe itself is all relative, depending on your standpoint. Nothing is ever the same to any particle in the universe - it cannot be by logical reasoning, since relative to any other particle, its physical states (mass, energy, velocity, direction) can never be the same, otherwise it would simply BE that particle (what would differentiate the two?).
Hope you enjoyed this post - there are a lot of things I wanted to say, but lost track of going off on lots and lots of different tangents. Perhaps though, I'll come back to them in more detail in later posts.
What is the value of 0/0? At first glance you might think that this actually has the value of 0, considering that if zero is divided by anything it is still zero! However, this isn't actually really true as you will soon find out.
Consider the basic algebraic principles: they state that if one number or expression is equal to another, then you may apply basic arithmetic operations to one side as long as you mirror them on the other. For example, the expression 7=14/2 is mathematically true. Multiplying both sides by 2 will give you 7x2=14 which of course is also true according to our number system. More generally, if a=b then ac=bc as well.
We can also apply this principle to the expression 0/0. Say, we are assuming that we do not know the value of 0/0, so we will set the expression equal to the letter X. So now X=0/0. Applying the principle that multiplying zero by both sides will result in an equal expression, we do so, giving us Xx0=0. But wait a minute; the value of any number multiplied by 0 is equal to 0, so can't X take on an infiinte set of values, not just 0? Strange as it may seem this is mathematically true, however we can't simply leave the definition of 0/0 as "all real or imaginary numbers", since this goes against the rules for forming legitimate funtions.
If we define the function f(X)=X/0, we should be able to set Y=X/0. However, this means that again Yx0=X, which as we have seen means Y is equal to any possible number. This cannot happen however, since the function isn't valid. It is not a many-to-one or one-to-one function. It is in fact a one-to-many function meaning that in our system of mathematics it is undefined due to the fact that for the value X=0, we get more than 1 equally likely result. So, in actual fact 0/0 is not 0, it is undefined.
There are a few strange things to note however, about multiplying and dividing by 0. The first of these things is that if Y=X/0, then if X takes on any value other than 0, the resulting value for Y is infinity.
So for example, if X=3, then Y=3/0, which of course is infinity. This becomes stranger however when we take Y as infinity in terms of the algebra.
if ∞=3/0
∞x0=3
and
0=3/∞
Now, that last statement makes sense: if 3 is divided infinitely, then it will approach 0. This at least seems feasible in terms of convergence to a limit. However, what about the statment ∞x0=3. Haven't we already assumed that any number multiplied by 0 is equal to 0? Infinity however multiplied by 0 seems to be equal to an infinite number of differnent numbers, as with the value of 0/0. So does this not mean that since both expressions are equal to the same vast range of different values, we can set ∞x0=X, where X comes from the expression Xx0=0, so X=0/0 and has a range of different values, just as ∞x0 has. However, since both expressions may take on a range of different values, then at the same time as ∞x0 is equal to 3 in one case, X may be equal to any number, for example 4, in the other. We then come out with the strange result 3=4. Now, this proves at least that many to one functions cannot exist at the same time as our normal number system, since strange results occur. The only solution to the problem is to set 0=∞. Now everything begins to seem more rational. By saying this we can now say that ∞=3/0 is not valid in the first place, since any number is 1 divided by itself, and that value only. So the only acceptable value for ∞=X/0 is X=0 (or X=∞ since we are now assuming 0=∞). This now becomes a much simpler 1 to 1 function, which is acceptable in mathematics.
Our other problem of Xx0=0 now becomes one which is much easier to solve. If 0=∞ then Xx∞=0 and the only value that X can now take is 0. This also means however that strangely ∞^2=0.
In summary, the strangeness of the whole dividing by zero thing, seems to have a logical solution: that 0 and infinity are one and the same. If you have read Godel, Escher, Bach by Douglas Hofstadter, you will be familiar with the term strange loop - and this is one. A strange loop is essentially a figure which comes back to its original value or state, as you get further and further away from the original: a strange sort of paradox. It is a weird concept, but one which perhaps could be used to explain why the universe seems to curve in a strange way I have realised: since it has been said that the universe's conept of space is undefinable in physical terms since if you travel infinitely far away from the place you are at then after an infinite distance you will come back to position 0 (or back to where you started). But of course it would be impossible for us to ever reach that infinite distance, since we would need to be able to travel at an infinite speed, and one thing is for certain: the speed of light is the limit.
Drawing Hands by M.C.Escher - a drawing which embodies strange loops
While reading about the amazing NASA New Horizons Space Probe (which is due to arrive at Pluto in less than a year!) I came across a webpage tracking the movement of the probe. On the webpage (http://pluto.jhuapl.edu/mission/whereis_nh.php), the software NASA uses to produce nice visuals of where the probe is and other information about it includes a special statistic: heliocentric velocity.
Now, initially I didn't know what this was, but looking at the description given:
Heliocentric Velocity. The current position graphic also notes the spacecraft's heliocentric velocity - its speed with respect to the Sun - in kilometers per second. One kilometer per second is equivalent to 0.62 miles per second, or 2,237 miles per hour.
This might seem like a pretty normal statement, but think about it carefully. If there has to be a central reference point for this probe's velocity to be measured from, then that must mean that all velocities are relative (which according to the theory of relativity, they are). This must also mean however, that the sun has a velocity, and that velocity is relative to other large stellar objects, or even things as small as atoms perhaps, which have a definite position in our universe. This makes sense, in earthly terms, where we measure our velocity relative to what can be regarded for all purposes as the stationary ground.
But, say that there existed just one object in the universe, with no other atoms around to help measure its velocity. Would that object ever have velocity? Actually, wouldn't that mean that even if a force was exerted on the object (somehow without another object causing it) that the object would seemingly simply be as good as stationary, since there would be no reference points to measure any acceleration in its movement from. Do not be fooled by the fact that if you were standing next to the object, that you would see it moving away from you, since this assumes that you would also be in this completely empty universe, meaning that there are now two objects which can be measured relative to each other (you and the object).
But of course, when I said that a force was caused, and implied that this happened without another object causing it, then this would be impossible. In fact, the only way for that object to have a force effected on it, would for it to split in two (in an unexplained and spontaneous explosion) and so resulting in two parts of the object having pushed away from each-other with equal force. Of course, we could not actually measure how large that force was in terms of our standard units since that would mean that we were there as well, and would be measuring the forces relative to the current system of our universe, which is wrong since the single object (now dual-object) universe is a different universe with different physical rules of relativity - our universe contains a complex set of objects relative to each other not comparable to that universe.
The way our universe is comparable to that single-to-dual object universe is that they seem to both have started in the same way. Perhaps our universe started as a very similar object. Of course, since that object was the only thing that existed, there was nothing to compare it to and so it existed relative to itself both in size and motion: meaning in fact that it had infinitely small size and motion (or infinitely large depending on how you want to think about it). This concept seems similar to the concept of a singularity - the thing that our universe is thought to have evolved from. Perhaps physical laws and rules emerged at the beginning of our universe in a similar way to the object splitting in that alternative universe, and did so for no apparent reason (this concurs with the spontaneous expansion idea of the Big Bang Theory). Of course, maybe I can now attempt to explain the complicated notion of 'non-existence' outside the universe: perhaps this simply implies that outside the boundaries of relative relationships between matter in our universe, nothing exists since there is simply nothing to measure it relative to, since that space is immeasurable relative to objects in our universe and we cannot simply get out a ruler and say how large objects outside the 'boundaries of the universe' are or how fast they are travelling.
This relativity might also explain (in a convoluted manner) the deveptively-simple, ever-so-weird concept of gravity. The explanation might be that gravity is simply a result of the relative equilibrium of all the particles of the universe having been disturbed by that unknown force which caused the Big Bang to begin. Ever since then, there has been an imbalance in that equilibrium, however since the universe is so complex and matter-full, the particles were unable to regain their original structure (the structure they held when they were a singularity) and have simply been trying to "locally compensate". What I mean by this is that instead of the whole network of the particles in the universe simply returning to their original relative positions, they have formed 'mini equilibria' in certain areas of the universe, such as on that lovable place we like to call earth, or even in our galaxy as a whole. Were every single particle in the universe to suddenly become aligned in such a way that they might be able to come together again to reform overall equilibria, that might be more favourable, and perhaps it has happened before (a la the theory of repeating universes: where universes continually form and collapse upon themselves to form cycles of singularities). Perhaps, this will happen again in the future? Nobody knows whether it will however, and if it will, when it will happen? Or is time, in this context, strangely relative as well? I leave that question to you.
Credit to:
http://pluto.jhuapl.edu/mission/whereis_nh.php
http://www.nasa.gov/mission_pages/newhorizons/main/#.VBSbcMJdVA0
We all encounter it everyday. We think about it constantly. We can hardly say a thing without mentioning it. Yes, what I'm talking about is of course time. Time to many people is very straightforward: it's the thing that happens all the time, no pun intended. It is present throughout our lives, dictating in what order things should happen and giving the chaos that is life a certain chronological structure. It is what makes or breaks history.
But why do we never ask ourselves the serious question or whether time exists or not? It seems pretty likely that it does. Just as we know the air is there from its effects ( it moves trees and creates the winds ) we know time is there since clocks and everything else for that matter, moves forwards at a constant rate throughout the day. Every second a second hand will move, every second a heart will beat. But is this just an illusion, a great veil we have drawn up in front of ourselves to cover up a greater truth. Many people have speculated as to whether this is true or not and as to whether this "greater truth" could be God or some other spiritual being.
I ask the question - is this seemingly constant thing really a constant, or is that just how we perceive it. There are a great many mysteries surrounding time. For a start basic physics questions it. What was time before the Big Bang theory for example. What is all this 'special relativity' stuff which Einstein was on about. Apparently time would be slower for someone moving more slowly - an athlete is actually moving more slowly through time than somebody sitting still. However the difference is so small it is unmeasurable ( almost ). But WHY?
Time is something we perceive to happen. We subconsciously expect a clock to tick and predict when it is next going to tick. But could we stop it if we tried? Not likely. Try it now, sit next to a clock and try to imagine it stopping at one tick, not moving forwards. It is impossible. Our minds almost want us to believe in time for some bizarre reason, as if stopping this inevitable continuation would cause an impossible change which might alter the running of the universe. Well... Perhaps not something that drastic but the fact remains that the thought of time stopping feels just out of reach, as if it is something that we know is there and could happen, but is beyond our mental capabilities. Perhaps this is the limitation that so many religious people search for when questioning how we can never understand God.
Another interesting scenario would be to imagine the world, only in reverse. Every animal backtracking, every seismic process in the earth's core suddenly reversing. Perhaps for five seconds. The universe would return to the state it was in five seconds ago. But what about time? Has time moved forwards in order to allow this to happen? Or has it moved backwards? It is confusing. If we say it has moved forwards then that would mean time was an irrelevant measurement, redundant and something unneeded. If there was a certain amount of time left for the earth, or for the sun to supernove, that has just been e tended by five seconds. Or has its. Nobody would notice a shift in time as sudden as this, since everyone's brains would return to the state they were five seconds prior to the 'time' shift. Therefore this process could actually be happening every second of every day. In fact we could all currently exist in some form in different periods of history. Everything could rely on this fact.
Well, that is all theoretical and is of course impossible to find out. There is only one truth. That is that times is completely redundant and irrelevant and useless, that is until we introduce the human factor.
We all know that almost everything in our universe is made up of what we so affectionately call matter. This matter makes up everything we see and use everyday, it even makes up what we've never seen or used. Distant planets, stars and galaxies - all made up of this weird substance. With every physical 'theory' there is always an element of indefinite uncertainty, and yet mass is one theory that we can almost solidly call "fact". Or can we? Have we ever really thought of what mass is? You may respond that mass is what 'is there'. But how do we know 'what's there' is there? Or what isn't seemingly 'there' is in reality... there? What is 'there'? What are 'space' and 'dimensions'? They didn't exist before the universe began.
Mass, as you can see, is a much more fiddly concept than you might ever imagine. On a large scale, relative to us, all masses obey a set of rules which we call 'forces' and 'physical laws', and yet on an atomic level, electrons do not. They seem to inadvertently flit around, sometimes seeming to be in two places at once! We cannot predict them entirely. Due to this a new theory was developed, called string theory, suggesting that everything in the universe is bonded together by strings so small that if you enlarged a hydrogen atom to the size of the galaxy the string would be only the size of a human hair! This theory may have yet to explain these tricky conundrums which inundate us in the universe. Yet, as with any theory, it is never perfect and there are always questions surrounding it. In fact, all the facts that we learn in everyday life, that we take for granted. All of them, are probably FALSE! They are in reality just attempts at trying to explain what happens around us. You may say that many of these theories are too robust to simply discard as mere attempts! Yet, that is exactly what philosophers and scientists would have said about ancient theories long ago. Back then, everyone believed that the world was the centre of the universe, that everything was made up of just four elements (earth, fire, air and water) and were completely perplexed by why there were different 'types of air', some of which could kill you! In response to these, instead of finding the correct solution, they simply tangled themselves up in knots, experimenting and trying to find an explanation using primitive theories. We know now that if pioneering scientists such as Isaac Newton and Albert Einstein hadn't come about, we would still be living, ignorant to the world around us.
This is why I believe that we have yet to come close to touching the reality of the universe. Our generation is simply another step towards simplifying these many "proven" theories and finding the real answer to life around us. Every generation brings with it new advancements and one day I think that in someone, somewhere's head the real solution will finally click. We are all on a constant adventure of mishaps and discoveries, some completely unintentional, and yet it is these accidents that will one day let us tumble into the bliss of understanding.
It doesn't have to be genial scientists or scholars which make these discoveries. Most of their minds have all been shaped and warped by the theories which surround us today. Most of them will never have the 'ignorance' to question scientific theories. This is why I believe that to advance in science we must all be willing to completely discard all that we have learnt, have an open mind, and fundamentally question the roots of stable theories. Without that there would be no scientific advancement whatsoever. In fact it is not knowing the answer which helps us advance, it is the question. As implied by the word 'creativity', you must 'create' the question to be able to think of finding the right answer. Even then there will always be more questions coming. What's to stop me or you finding the next question?
Air is all around us all the time. It surrounds us
every single minute of our lives, from start to finish: literally. Air is
extremely important, and without it life may never even have come into
existence. Air is mixture which helps us do things such as breathe, make fires
and fly aeroplanes. One tiny change in the composition of air and we might have
had very different lives, if none at all!
A common misconception is that air is just one ‘element’.
This is completely untrue! Air is not on the periodic table (you can check if
you like). Air isn’t even one simple compound. In fact, air is actually a
mixture of a variety of different elements and compounds in gaseous form, the
most notorious of which being oxygen. However, this is not the gas in most
abundance, in fact if it was we would most probably be dead, as pure oxygen is
poisonous!
Air is actually made up mainly of nitrogen (around 78%),
oxygen generally only makes up about 20-21% of air. There are also small
amounts (around 1%) of noble gases such as argon and helium in the air.
Finally, air contains substances essential for plant life: carbon dioxide (0.03%)
and water vapour (0.97%, but it can vary!) Plants need carbon dioxide and water
for the process of photosynthesis, where they convert these substances to
glucose and oxygen in the process of photosynthesis. You may have heard of
humidity levels. Since the amount of water in the air can vary, this can raise
or drop humidity levels. It can go from 4% to 0.5%!
Air however does not only contain these set substances. It also
contains minutely small amounts of other substances such as aerosols (which are
tiny particles of dust from the ground or from volcanic ash.) If you can
imagine zooming up into the sky, the composition of air there would be very
different. There lies the notorious gas known as ozone, which environmentalists
are currently making a big fuss about (due to the theory of global warming).
There is also a lot more helium and hydrogen up there, as they are lighter
elements, less dense than the others, so when they float up the others sink
down.
You have probably heard of air pressure as well. This is
just basically the weight of the air pushing down on everything on the earth –
including us! Air pressure is measure in something called Pascal units which is
just how many kilograms of ‘weight’/’force’ (measured in Newtons – “N”) act
over 1 m2 of area. So if 3kg of air was pressing down on 1 m2 of
area then the air pressure would be 3 Pascals. However the real pressure of the
air comes nothing close to that. In fact for every 1 m2 of area on
the earth, air pressure results in a force equivalent to the weight of a large
elephant pushing down on it! You may ask why we aren’t crushed by this force.
This is because the blood in our bodies pushes out with an equivalent pressure
and the two cancel out. This also explains why when we enter different areas of
pressure, for example when flying on a plane, sometimes people get nosebleeds
as the difference in pressure causes the blood vessels to expand and burst.
Imagine if you entered a vacuum (space) without a special suit, you would just
burst due to the pressure of your blood being too strong for your body to
withstand!
Just came across this while looking at radiation from mobile phones on the 'physics.org' website. It shows how much radiation you can get from doing different things and loads of other random information. Thought it might be interesting - enjoy. (Click here for a bigger view.)
I was reading about elasticity and came across the basic principles:
Every material has a certain degree of elasticity
There is a point, called the elastic limit, where the material permanently deforms and can't be returned back to it's original shape (it gains a new elastic limit as well). This is also called plastic deformation or plasticity.
Robert Hooke described the amount stretched as directly proportional to the force it would produce and vice versa (e.g. a bigger gravitational force acting down upon the elastic material - hanging a weight off of it - would produce a bigger stretch/extension)
However, I couldn't quite understand how this actually worked on a molecular level. It took me a while to find all the information, but I eventually understood (after much searching on Google!).
So here is the explanation I collected up (from various sources):
Basically, materials can stretch due to inter-molecular forces between atoms. There are different charges in different parts of the material and these attract. If you try to squash the material like charges repel too much and so the material tends to try to stretch out again. If you stretch the material the opposite charges attract too much and the material tends to attempt to go back to its original shape. This shape is the shape in which the material is balanced: there is an equal amount of attraction and repulsion and so this is the preferred state for the material.
However, there is also the aspect of the elastic limit. This works because beyond a certain point the atoms become to far apart or close together to be pulled back into their original positions. The atoms have so much force exerted on them that they displace. However, once they have displaced they will settle in their new positions and assume a new elastic limit. This explains why elastic bands snap: the atoms move so far apart from each other that the whole material gets pulled apart!
I hope this makes things slightly clearer. If you don't understand anything just comment below!
Whether it makes a difference or not all depends on size...
Now, as I mentioned in my previous post, the terms 'centre of mass' and 'centre of gravity' can be used almost interchangeably. However, this is only when we refer to relatively small objects, such as those which we find on the earth.
The difference between centre of mass and centre of gravity is fairly simple.
The centre of mass is a single point inside (or outside) any object where all of its mass effectively acts. In a regular 3D shape, such as a sphere, this would be the dead centre, however in a more complex shape it would be different.
The centre of gravity however, is where all gravity acts on an object. On earth the centre of mass is practically where all gravity acts so they can be used interchangeably. However, we know that gravitational pull depends on two things: distance between two objects and the mass of the object. The mass of the object will obviously always stay the same, however the distance from the object can change.
Consider an object as big as the moon. The distance from the earth on one side, would be much smaller than the opposite side. This means that since there is a substantial difference in pull between different parts of the 'object', the centre of gravity will be affected.
So there you go. There is always a difference between centre of mass and centre of gravity, but sometimes it is so minute that we consider it insignificant. This is due to the object being fairly small. However as the object gets larger, we begin to feel the need to distinguish between the two.
If you have any questions then, again, please feel free to leave them in the comments box below.
Two forks seemingly magically balance on the rim of the cup, with the support of a mere toothpick.
Watch the video
Here is a video of an experiment I did (see it on youtube).
How it works:
This is due to the law of centre of gravity.
This law states that every objects has a point, where all gravity will effectively act. This is the midpoint of all the mass in the object. In a simple shaped structure such as a cube, this will just be in the middle, as there is an equal amount of mass in all directions of that point.
However, in the complicated, but symmetrical structure of two forks wedged together, the centre of gravity will act somewhere in the air (that is why two forks dip inwards if you hold them by the prongs)! I know this is complicated to understand, but the rest of the object does not affect the gravitational pull. If you piled up ten more forks, equally on both sides, the structure would still balance (if you had a really strong toothpick!).
Some people may use the term 'centre of mass' as well. On earth we can use these terms interchangeably, however in different gravitational fields, there is a difference.
If you are confused about the difference between centre of mass and centre of gravity, don't worry, as I will go over this in a later post, if you can't wait till then, click here.
This may look fairly complicated, but actually its simply just the composition of the elements. Here it is in word equation form.
Although this may be slightly biology related it is also chemistry related AND physics related. So we know that when we eat food, to get energy we require the substance glucose (which is a molecule in the food we eat) to be burned in oxygen to produce carbon dioxide and water as by-products. However, most importantly this reaction produces energy, namely in the form of heat. Firstly here is the chemical equation:
Glucose + Oxygen → Carbon Dioxide + Water (+ENERGY:- 2880 kJ to be precise)
kJ or kilojoules are basically a unit to measure energy in (1000 joules, as the prefix "kilo" implies, as in kilometres or kilograms). You may have also heard of calories being used, especially in terms of food. They can be directly compared.
4.1868 kilojoules = 1 Calorie
One calorie is the energy needed to raise the temperature of exactly one gram of water by one degree Celsius. So, one kilojoule is just 1/4 of that amount of energy approximately.
So, anyway, we know that when these materials are transported to the cells, this chemical reaction occurs, producing heat energy. The equations are balanced. The question is, where did the heat energy come from?
We know that it is theoretically possible to convert matter into energy (as described by Einstein's equation of E=MC^2), but obviously no matter has been converted into energy for three reasons:-
The equations are balanced
You'd need immense heats for this to happen which we can't even produce on earth. Imagine this type of heat in your body!
If we actually could produce anything close to these types of heat in our bodies, it wouldn't exactly be gaining energy would it?
So just what happens to release this energy?
This question can be answered simply if you know about atoms. Atoms always try to gain the lowest energy levels possible, as energy is stored in their chemical bonds, to keep them joined together in compounds. Glucose is fairly happy as glucose and oxygen is quite content with itself too. Unfortunately for them, when they come together, they realise that there is a another state they would prefer to be in, namely in the rearranged forms of water and carbon dioxide. You can of course probably guess why...
They need less energy!
Another law states that energy cannot be destroyed (although it can be theoretically created from matter). So where has all the excess energy gone that is not needed any more?
It's released as heat energy in your body!
So that answers the question of where the energy came from, but also describes sort of what chemical energy is, and how that becomes heat energy. If you have any questions or corrections, just leave them in the comments.
Momentum is a measure of how much inertia an object has. This means how hard it would be to change its velocity. All moving objects have momentum, as every object has mass and momentum is mass multiplied by velocity. If an object has a high momentum then its going to be harder to change its velocity than an object with a smaller momentum. You can think of momentum a bit like determination. If someone has a bigger determination to finish a task then they are more likely to succeed, as they cannot be deterred from their path as easily as someone with a smaller determination. Similarly, an object with greater momentum has greater inertia and therefore is less likely to have its velocity changed or its direction altered. This is the general equation to calculate the momentum of an object.
f = m x a
force = mass x acceleration
If you had an apple thrown at you at 5m/s and another apple thrown at you at 10m/s then blatantly you can see that the faster apple would be harder to stop. This apple, pretending it had a mass of 0.5 kg, would have a momentum of 0.5 kg x 10 m/s = 5 kg m/s.That is the unit of momentum: kg m/s. The other apple on the other hand would have a momentum of half that: 2.5 kg m/s (0.5 kg x 5 m/s).
However it is just not sufficient to describe momentum with just these numbers, because momentum is a vector quantity This basically means that it has not only magnitude, but also direction (like speed and velocity - if you don't understand this visit this link.) This means of course that we would have to say the direction of the apple. For example South East or North North West.For example.
Now we've come to Newton's last law of motion. This one's pretty simple to be honest. Here it is:
"For every action there is an equal and opposite reaction."
Yoshi knows his physics!
It's quite short, isn't it. The definitions short and simple too, whenever a force acts (a push or a pull - the action), then another force acts in the opposite direction with exactly the same amount of force (what we call the reaction force. So when you punch a wall, the wall punches back and that's why you're hand doesn't
move: the wall is pushing back with an equal force. But what if your hand goes through the wall I hear you ask? Well, that's the clever bit. Since there's no more force to support the wall the ground pushes the opposite way to account for the remaining force and so you topple over as your feet are pushing one way, your arms are moving in the other.
Another example is in a tug of war. When you pull on the rope you have to dig your feet into the ground to stop yourself falling over. You wouldn't be able to do it on ice! So when you pull your feet push the other way with an equal force.
You can see this if you step onto one of those really small boats. Try and walk forwards and you'll find the boat moves backwards. This is because your feet are pushing the other way!
If you have any questions please let me know in the comments :D!
Now another great thinker whom I'm sure you've heard of - the infamous Aristotle - once said that the force of an object is equal to its mass multiplied by its velocity. Now any one with common sense would believe this to be true. However, Aristotle did not take into account the amazing forces of friction and this blinded his insight. However of course as you know, another clever man, called Sir Isaac Newton came and proved this fellow wrong with his second law of motion:
"The relationship between an object's mass m, its acceleration a, and the applied force F is F = ma"
In other words, he took upon Galileo's original idea, but tweaked it so that it was RIGHT. He found that when you took into account frictional forces, force was not equal to mass multiplied by velocity, but mass multiplied by acceleration. As he proved in his first law, an object tends to maintain a constant velocity and when a force is applied it does not keep this velocity, but accelerates in accordance to the force. Since Aristotle didn't think about friction, he saw an object slowed down if force was removed, and so thought that you needed to apply force to maintain a constant velocity, which we of course know is wrong.
This is one of Newton's most powerful laws as it gives us these useful equations:
Force = Mass x Acceleration
and from this...
Acceleration = Force / Mass
and...
Mass = Force / Acceleration
You can think of an example of this law very easily. Think of a huge ball of mass 10 stone (or 60 kg), then another ball of mass 20 stone (or 120 kg). If you imagine these two balls each being rolled towards you in turn at the same acceleration (ouch!) which would hurt more? The answer of the heavier ball is obvious. This is due to it having double the force due to its mass being doubled. Similarly you could think of two balls of the same mass each being rolled at you at different accelerations. The one speeding up more quickly would produce more force. You can see from the derivatives of the original equation that we can calculate mass and acceleration as well as force if we have the other values.
I hope you know understand this law, crucial to physics as we know it! If you don't, or just generally have something you'd like a post/topic on, just feel free to leave a comment below :).
In this post I'll try to explain to you what inertia is and how it works.
Here is the Newton's first law of motion: "Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it."
In simple this means that:
If something is moving at a constant speed (e.g. a car going at 40mph) or even if it is stationary, it will tend to remain at that speed unless a force acts on it (e.g the friction on the ground or in the air - air resistance).
On earth we don't often see this directly as forces are constantly acting on everything such as gravity, friction and air resistance. However, if we were to imagine a car being pushed off a ramp in deep space at a set speed, for example 10mph, it would theoretically keep travelling at this speed forever until some force came into contact with it (hitting something for example).
Galileo, before Newton, also developed a law called the law of Inertia. This basically means that an object which is at rest tends to stay like that unless another force acts upon it.
This is because of friction of course. Have you ever noticed that when you try to push something heavy on the ground you need a huge force at the start, but when it gets going its much easier? You may also have noticed that as soon as you stop pushing the object quickly stops.
Friction does this because, if you can imagine, every object (even flat objects) have uneven surfaces. They have rumps and bumps all over them and friction is caused by the different bumps getting stuck between each other on two surfaces. Inertia happens because when an object is at rest the object's bumps are
nicely settled into the surface beneath it's cavities. You need a big force to get the bumps out, and then after that the object just skips over the cavities making it easier to push. Once you stop pushing the object stops once more.
An example of this is in a clock-work mouse. When you wind up the mouse and set it going it goes for a while, and sometimes it stops. If you then give it a little tap then the mouse starts going again. Know you know why.
I hope this has made the law clearer to you. If not, or if you have any questions, please feel free to leave them in the comments below. I'll be posting on the other laws of motion soon.
We all know about the laws of physics and gravity and the like. We know that previous societies thought that the sun and stars revolved around the earth. We also however know about relativity and the position and speed of objects varies in relation to other objects. For example a car travelling at 30 mph would see another car travelling at 20mph in the same direction as travelling at 10mph.
There is a saying that very egoistic people think about themselves 'the world revolves around them'. Who says that this isn't true.
Try getting up and walking around the room. YOU are moving around the ROOM, correct? Try thinking that you are stationary - the center of the universe - and are pushing the room away from under your feet. That you are constantly located in the same position.
It's a strange thought, but there is no theory about the center of the universe, therefore there is nothing to disprove this theory. For all we know you sitting at your computer or mobile phone or whatever could be moving the universe as you take each step. For all we know gravity could be working in reverse. You could be moving the world, which the sun is revolving round, which the planets are revolving round, which the solar system is consequently affected by, which the whole universe is constantly affected by! You could argue the world is seen to be moving and revolving. But what's to say that the whole universe isn't moving and giving that impression.
Think about holding an object (for example a cup) on a table in place on top of a table cloth then pulling the table and the table cloth from underneath it. If you then asked the cup who was ignorant to the rest of the room (the universe) to relate its experiences it would say that IT moved along and off the table. You could think about us as human beings as that cup.
This also leads onto another thing. What is to say that you or me or anyone isn't the only properly thinking human in the world. We could each be on our own in the world, the people and events happening around us CREATED for us, made specifically for one person (yourself). You can never see into other people's minds to see if they think in the exact same way. Who is to say that any of the events in history (before we were born) actually happened. WE weren't there to SEE them or EXPERIENCE them, and until someone invents a time machine we never will.
Just a couple of things to get you thinking. Feel free to comment about your thoughts below :).
Just what the label says- data transferred by light along fibers (basically)
Here are three things I know about you:
You may be under the impression that fiber optics refers mainly to internet transmissions
You sort of maybe think you know what they are
You either completely agree with the comments above or were offended by them.
If you feel offended I recommend wasting your precious time feeling offended and arrogant instead of reading this and learning. As this won't affect me in any way whatsoever. I'll tell you a story about that in the next post ;).
Read this post and get all the information for half the price. Every little helps.
So, anyway lets get down to what fiber optics actually are.
Now I'm sure you've heard of fiber optic cables. In short they are long strands of pure glass which act like electrical wires, except they transmit the information using light (infra-red radiation wavelength). They're as thin as human hairs and look something like the branches on those little decorative trees with light coming out of the ends. They can transmit digital information over long distances and have many (other than super-fast internet) in lots of different categories, here are just a few:
Tiny cameras which can see inside really small areas
Lasers for surgery
Light guides - they can shine bright lights on hard to reach places
You need lots of optical fibers to produce something usable as they are so thin, and so lots of these bundled together are collectively called a fiber optic bundle.
The composition of a fiber-optic cable
It's amazing to see how you could engineer these wires ,even though they are so thin, to make them up of three layers. Each of the wires are made up of three main parts.
Core - The thin glass tube at the center which the light travels along
Buffer Coating - The middle part which basically acts as a shield to protect the wire
Cladding - The outer coating which reflects the light back to the core to prevent loss of information
There are two types of fiber-optic cable
Single-mode fibers - Transmit data via infra-red laser radiation
Multi-mode fibers - Transmit data from LEDs via infra-red radiation
I will talk more about radiation and the electromagnetic spectrum in later posts (if you're interested)
So how does the light get through the wire?You may or may not have been wondering.
Well, since light travels in straight lines, it doesn't bend along the wire. It basically bounces along the wire in zigzags, getting reflected off the cladding, meaning it can travel great distances. This is called total internal reflection as none of the light is absorbed by the cladding so it can basically keep going on and on and on and on and on...
However, the light signal does degrade due to the glass never being 100% pure and reflective, and this is why high quality fiber-optic cables can transmit data longer distances without "losing quality/information". The higher quality the fiber the purer the glass in short.
How the information gets from A to B...
Three stages... Three different jobs... One at the start... Several in the Middle... One at the end.
Transmitter - This produces the light signal by encoding it from the information provided and beaming it along the cable(example - makes video collected from camera at the end of the optical fiber into an encoded light signal).
Optical Re-generators - As I mentioned before, the light signal degrades (especially over long distances). These are situated at intervals along the fibers and just give the signal a boost every now and again to keep it strong.
Optical Receiver - This is what translates the message back into the form the user/machine at the other end wants (example - video from the camera at the other end of the optical fiber).
What really is so great about fiber optics?
Cheap - Lots of these cables can be made more cheaply than copper wires, for example transmitting electrical signals
Thin - They are obviously very small and lightweight making their uses very versatile and open-ended (for example - there could be more data being sent at the same time in the same bundle of wire)
Better quality - The signal degrades less and the data being received is of a higher quality
Non-flammable - They don't catch fire. Pretty self-explanatory advantage.
Low power - They take up much less energy. Hooray! :D
I thought you might like to watch a VIDEO of how fiber-optic cables were made so...
So I hope you understand fiber optics more now. I'm open to complete criticism or questions in the comments. Remember, no-one is perfect and therefore I have DEFINITELY made a mistake in this post. See you next time.
Firstly, welcome to this blog.
Now, before you read any further I feel that it would be pointless of you following these posts if you're not into any of the things I will be posting about, If you pass the following test I have devised and make it to the end of the page without committing suicide then this blog is for you.
Have you ever used the internet? Yes - That's quite surprising. No - I suggest you should try it.
Can you read? Yes - Perfect :) No - Well I'm sure we can improve on that.
Are you alive right now? Yes - Well, that's a start. No -
If you are still reading right now then you're obviously interested. If you're not here reading this right now, but still know that I have written about you not reading this or reading this without you actually being present to read this then you are some sort of super-human being and deserve to read this blog anyway. So either way, this blog is for you.
If you didn't understand any of the sentence above...
You obviously can't read which is in ways very difficult to understand seeing as you couldn't read two seconds ago but can now read
You phrased the sentence wrongly and meant the grammatical construction and word order with repeated phrases and inverted phrases confused you to the point of loss of hope in humanity.
If you can read this word now ---->>> , then you have in theory passed the test. Although you couldn't have been reading the word at the time you read 'now' because you would have had to have two brains, effectively reading the two words simultaneously and that is not impossible (as are most things in life), although it is highly unlikely.
If you are reading this sentence at the moment (that's better), you may have skipped to the end and cheated because you couldn't be bothered, but that just demonstrates initiative and you have also passed the test.
