TedTest

From the Ted Talk by Chad Orzel: What is the Heisenberg Uncertainty Principle?

Unscramble the Blue Letters

The Heisenberg Uncertainty Principle is one of a hdfanul of ideas from quantum physics to expand into general pop cuultre. It says that you can never simultaneously know the exact position and the exact speed of an object and shwos up as a metaphor in everything from literary criticism to sports cmmnotarey. Uncertainty is often explained as a result of measurement, that the act of msiernaug an object's position changes its speed, or vice versa. The real origin is much deeper and more amazing. The Uncertainty Principle eistxs because everything in the universe behaves like both a particle and a wave at the same time. In quantum mechanics, the ecaxt position and exact speed of an object have no meaning. To understand this, we need to think about what it means to behave like a pcitlrae or a wave. Particles, by definition, exist in a single place at any instant in time. We can resenrpet this by a graph showing the probability of finding the ocejbt at a particular place, which looks like a spike, 100% at one specific position, and zero everywhere else. Waves, on the other hand, are decnbriatsus spread out in scape, like rlippes covering the surface of a pond. We can clearly identify features of the wave prettan as a whole, most importantly, its wavelength, which is the distance between two neighboring peaks, or two neighboring valleys. But we can't assign it a sligne position. It has a good probability of being in lots of different places. Wavelength is enssatiel for quantum physics because an object's wavelength is related to its momentum, mass times velocity. A fast-moving object has lots of momentum, which corresponds to a very short wavelength. A heavy object has lots of momentum even if it's not moving very fast, which again means a very short wavelength. This is why we don't notice the wave nature of everyday objects. If you toss a baseball up in the air, its weagnvleth is a billionth of a trillionth of a trillionth of a meter, far too tiny to ever deetct. Small things, like atoms or electrons though, can have wavelengths big enough to measure in physics experiments. So, if we have a pure wave, we can measure its wavelength, and thus its momentum, but it has no position. We can know a particles position very well, but it doesn't have a wavelength, so we don't know its momentum. To get a particle with both position and momentum, we need to mix the two pictures to make a gaprh that has waves, but only in a small area. How can we do this? By combining waves with different watlhevnegs, which means giving our quantum object some possibility of having different metomna. When we add two waves, we find that there are places where the peaks line up, making a bigger wave, and other places where the peaks of one fill in the valleys of the other. The result has regions where we see waves separated by roiegns of nothing at all. If we add a third wave, the regions where the waves cancel out get bigger, a ftoruh and they get bigger still, with the wavier regions becoming nraoewrr. If we keep adding waves, we can make a wave pkaect with a clear wavelength in one smlal region. That's a quantum object with both wave and particle nature, but to accomplish this, we had to lose certainty about both position and momentum. The positions isn't restricted to a single point. There's a good probability of finding it within some range of the center of the wave packet, and we made the wave packet by adding lots of waevs, which means there's some probability of finndig it with the momentum corresponding to any one of those. Both position and momentum are now urcteanin, and the uncertainties are connected. If you want to reduce the position uncertainty by making a smaller wave packet, you need to add more waves, which maens a bigger momentum untcntrieay. If you want to know the mmtouenm better, you need a bigger wave packet, which means a bigger position uncertainty. That's the Heisenberg Uncertainty Principle, first stated by German physicist werenr Heisenberg back in 1927. This uncertainty isn't a matter of measuring well or badly, but an inevitable ruelst of combining particle and wave nature. The Uncertainty Principle isn't just a practical limit on measurment. It's a limit on what properties an object can have, built into the fnmatauednl structure of the uevsirne itself.

Open Cloze

The Heisenberg Uncertainty Principle is one of a _______ of ideas from quantum physics to expand into general pop _______. It says that you can never simultaneously know the exact position and the exact speed of an object and _____ up as a metaphor in everything from literary criticism to sports __________. Uncertainty is often explained as a result of measurement, that the act of _________ an object's position changes its speed, or vice versa. The real origin is much deeper and more amazing. The Uncertainty Principle ______ because everything in the universe behaves like both a particle and a wave at the same time. In quantum mechanics, the _____ position and exact speed of an object have no meaning. To understand this, we need to think about what it means to behave like a ________ or a wave. Particles, by definition, exist in a single place at any instant in time. We can _________ this by a graph showing the probability of finding the ______ at a particular place, which looks like a spike, 100% at one specific position, and zero everywhere else. Waves, on the other hand, are ____________ spread out in _____, like _______ covering the surface of a pond. We can clearly identify features of the wave _______ as a whole, most importantly, its wavelength, which is the distance between two neighboring peaks, or two neighboring valleys. But we can't assign it a ______ position. It has a good probability of being in lots of different places. Wavelength is _________ for quantum physics because an object's wavelength is related to its momentum, mass times velocity. A fast-moving object has lots of momentum, which corresponds to a very short wavelength. A heavy object has lots of momentum even if it's not moving very fast, which again means a very short wavelength. This is why we don't notice the wave nature of everyday objects. If you toss a baseball up in the air, its __________ is a billionth of a trillionth of a trillionth of a meter, far too tiny to ever ______. Small things, like atoms or electrons though, can have wavelengths big enough to measure in physics experiments. So, if we have a pure wave, we can measure its wavelength, and thus its momentum, but it has no position. We can know a particles position very well, but it doesn't have a wavelength, so we don't know its momentum. To get a particle with both position and momentum, we need to mix the two pictures to make a _____ that has waves, but only in a small area. How can we do this? By combining waves with different ___________, which means giving our quantum object some possibility of having different _______. When we add two waves, we find that there are places where the peaks line up, making a bigger wave, and other places where the peaks of one fill in the valleys of the other. The result has regions where we see waves separated by _______ of nothing at all. If we add a third wave, the regions where the waves cancel out get bigger, a ______ and they get bigger still, with the wavier regions becoming ________. If we keep adding waves, we can make a wave ______ with a clear wavelength in one _____ region. That's a quantum object with both wave and particle nature, but to accomplish this, we had to lose certainty about both position and momentum. The positions isn't restricted to a single point. There's a good probability of finding it within some range of the center of the wave packet, and we made the wave packet by adding lots of _____, which means there's some probability of _______ it with the momentum corresponding to any one of those. Both position and momentum are now _________, and the uncertainties are connected. If you want to reduce the position uncertainty by making a smaller wave packet, you need to add more waves, which _____ a bigger momentum ___________. If you want to know the ________ better, you need a bigger wave packet, which means a bigger position uncertainty. That's the Heisenberg Uncertainty Principle, first stated by German physicist ______ Heisenberg back in 1927. This uncertainty isn't a matter of measuring well or badly, but an inevitable ______ of combining particle and wave nature. The Uncertainty Principle isn't just a practical limit on measurment. It's a limit on what properties an object can have, built into the ___________ structure of the ________ itself.

Solution

uncertainty
object
space
represent
commentary
graph
detect
universe
essential
culture
disturbances
regions
shows
particle
fourth
narrower
measuring
ripples
single
result
uncertain
momenta
wavelength
finding
wavelengths
fundamental
exists
pattern
handful
packet
exact
waves
means
momentum
small
werner

Original Text

The Heisenberg Uncertainty Principle is one of a handful of ideas from quantum physics to expand into general pop culture. It says that you can never simultaneously know the exact position and the exact speed of an object and shows up as a metaphor in everything from literary criticism to sports commentary. Uncertainty is often explained as a result of measurement, that the act of measuring an object's position changes its speed, or vice versa. The real origin is much deeper and more amazing. The Uncertainty Principle exists because everything in the universe behaves like both a particle and a wave at the same time. In quantum mechanics, the exact position and exact speed of an object have no meaning. To understand this, we need to think about what it means to behave like a particle or a wave. Particles, by definition, exist in a single place at any instant in time. We can represent this by a graph showing the probability of finding the object at a particular place, which looks like a spike, 100% at one specific position, and zero everywhere else. Waves, on the other hand, are disturbances spread out in space, like ripples covering the surface of a pond. We can clearly identify features of the wave pattern as a whole, most importantly, its wavelength, which is the distance between two neighboring peaks, or two neighboring valleys. But we can't assign it a single position. It has a good probability of being in lots of different places. Wavelength is essential for quantum physics because an object's wavelength is related to its momentum, mass times velocity. A fast-moving object has lots of momentum, which corresponds to a very short wavelength. A heavy object has lots of momentum even if it's not moving very fast, which again means a very short wavelength. This is why we don't notice the wave nature of everyday objects. If you toss a baseball up in the air, its wavelength is a billionth of a trillionth of a trillionth of a meter, far too tiny to ever detect. Small things, like atoms or electrons though, can have wavelengths big enough to measure in physics experiments. So, if we have a pure wave, we can measure its wavelength, and thus its momentum, but it has no position. We can know a particles position very well, but it doesn't have a wavelength, so we don't know its momentum. To get a particle with both position and momentum, we need to mix the two pictures to make a graph that has waves, but only in a small area. How can we do this? By combining waves with different wavelengths, which means giving our quantum object some possibility of having different momenta. When we add two waves, we find that there are places where the peaks line up, making a bigger wave, and other places where the peaks of one fill in the valleys of the other. The result has regions where we see waves separated by regions of nothing at all. If we add a third wave, the regions where the waves cancel out get bigger, a fourth and they get bigger still, with the wavier regions becoming narrower. If we keep adding waves, we can make a wave packet with a clear wavelength in one small region. That's a quantum object with both wave and particle nature, but to accomplish this, we had to lose certainty about both position and momentum. The positions isn't restricted to a single point. There's a good probability of finding it within some range of the center of the wave packet, and we made the wave packet by adding lots of waves, which means there's some probability of finding it with the momentum corresponding to any one of those. Both position and momentum are now uncertain, and the uncertainties are connected. If you want to reduce the position uncertainty by making a smaller wave packet, you need to add more waves, which means a bigger momentum uncertainty. If you want to know the momentum better, you need a bigger wave packet, which means a bigger position uncertainty. That's the Heisenberg Uncertainty Principle, first stated by German physicist Werner Heisenberg back in 1927. This uncertainty isn't a matter of measuring well or badly, but an inevitable result of combining particle and wave nature. The Uncertainty Principle isn't just a practical limit on measurment. It's a limit on what properties an object can have, built into the fundamental structure of the universe itself.

Frequently Occurring Word Combinations

ngrams of length 2

collocation	frequency
uncertainty principle	3
heisenberg uncertainty	2
quantum physics	2
exact position	2
exact speed	2
good probability	2
short wavelength	2
wave nature	2
quantum object	2
wave packet	2
position uncertainty	2

Important Words

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act
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