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 handful of ieads from quantum psihycs to expand into general pop culture. It says that you can never solntimaslueuy know the exact position and the ecxat speed of an object and sohws up as a metaphor in everything from literary criticism to sports commentary. Uncertainty is often eepxniald as a rlseut of measurement, that the act of msanurieg an object's position changes its speed, or vice versa. The real origin is much deeper and more amazing. The Uncertainty picplinre etxiss because everything in the usivrnee behaves like both a particle and a wave at the same time. In qaunutm mechanics, the exact position and exact speed of an object have no meaning. To udaennrtsd this, we need to think about what it means to behave like a particle or a wave. Particles, by definition, exist in a single pcale at any instant in time. We can represent this by a garph showing the probability of finding the object at a particular place, which looks like a spkie, 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 pekas, or two nehigonbirg 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 ntraue of everyday objects. If you toss a baseball up in the air, its wgeleavnth is a billionth of a trillionth of a trillionth of a meter, far too tiny to ever dceett. Small things, like atoms or erctleons though, can have wavelengths big enough to measure in physics experiments. So, if we have a pure wave, we can musaere its wavelength, and thus its munotemm, 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 pctrilae with both position and momentum, we need to mix the two pictures to make a graph that has waves, but only in a samll area. How can we do this? By combining waves with different wavelengths, which means gniivg our quantum object some pisltbsioiy 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 cecanl out get bigger, a fourth and they get bigger still, with the wavier regions becoming narrower. If we keep adding weavs, we can make a wave packet with a claer wavelength in one small region. That's a quantum object with both wave and particle nature, but to aoclpcsimh this, we had to lose certainty about both position and momentum. The psintoois isn't restricted to a single point. There's a good pitrloibaby of finding it within some rngae of the cenetr of the wave packet, and we made the wave packet by adding lots of waves, which menas 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 mnakig 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 maettr of measuring well or badly, but an inevitable result of cnmiibong particle and wave nature. The Uncertainty Principle isn't just a parccital limit on measurment. It's a limit on what properties an object can have, built into the fundamental structure of the universe itself.

Open Cloze

The Heisenberg Uncertainty Principle is one of a handful of _____ from quantum _______ to expand into general pop culture. It says that you can never ______________ know the exact position and the _____ speed of an object and _____ up as a metaphor in everything from literary criticism to sports commentary. Uncertainty is often _________ as a ______ 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 _________ ______ because everything in the ________ behaves like both a particle and a wave at the same time. In _______ mechanics, the exact position and exact speed of an object have no meaning. To __________ this, we need to think about what it means to behave like a particle or a wave. Particles, by definition, exist in a single _____ at any instant in time. We can represent this by a _____ showing the probability of finding the object at a particular place, which looks like a _____, 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 _____, or two ___________ 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 ______ 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 _________ though, can have wavelengths big enough to measure in physics experiments. So, if we have a pure wave, we can _______ its wavelength, and thus its ________, 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 ________ with both position and momentum, we need to mix the two pictures to make a graph that has waves, but only in a _____ area. How can we do this? By combining waves with different wavelengths, which means ______ our quantum object some ___________ 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 ______ out get bigger, a fourth and they get bigger still, with the wavier regions becoming narrower. If we keep adding _____, we can make a wave packet with a _____ wavelength in one small region. That's a quantum object with both wave and particle nature, but to __________ this, we had to lose certainty about both position and momentum. The _________ isn't restricted to a single point. There's a good ___________ of finding it within some _____ of the ______ of the wave packet, and we made the wave packet by adding lots of waves, which _____ 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 ______ 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 ______ of measuring well or badly, but an inevitable result of _________ particle and wave nature. The Uncertainty Principle isn't just a _________ limit on measurment. It's a limit on what properties an object can have, built into the fundamental structure of the universe itself.

Solution

physics
simultaneously
small
result
nature
explained
neighboring
peaks
possibility
measure
ideas
spike
practical
quantum
graph
exact
clear
universe
place
matter
electrons
combining
particle
measuring
giving
cancel
means
accomplish
probability
shows
principle
wavelength
making
center
momentum
range
exists
understand
waves
detect
positions

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

accomplish
act
add
adding
air
amazing
area
assign
atoms
badly
baseball
behave
behaves
big
bigger
billionth
built
cancel
center
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clear
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connected
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culture
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electrons
essential
everyday
exact
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explained
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features
fill
find
finding
fourth
fundamental
general
german
giving
good
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hand
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heisenberg
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identify
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instant
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line
literary
lose
lots
making
mass
matter
meaning
means
measure
measurement
measuring
measurment
mechanics
metaphor
meter
mix
momenta
momentum
moving
narrower
nature
neighboring
notice
object
objects
origin
packet
particle
particles
pattern
peaks
physicist
physics
pictures
place
places
point
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pop
position
positions
possibility
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probability
properties
pure
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range
real
reduce
region
regions
related
represent
restricted
result
ripples
separated
short
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wave
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wavier
werner