heisenberg uncertainty principle definition

With a 10% uncertainty associated with that number. So the linear momentum P is equal to the mass times the velocity. And since we know the mass of an electron, we can actually calculate So the velocity of anĮlectron in the ground state of a hydrogen atom using the Bohr model, we calculated that to be 2.2 times 10 to the six meters per second. Alright, we also did some calculations to figure out the velocity. And this is just a roughĮstimate of the size of the hydrogen atom using the Bohr model, with an electron in the ground state. So two times that number would be equal to 1.06 times 10 to So if we wanted to know theĭiameter of that circle, we could just multiply the radius by two. Of the first energy level, is equal to 5.3 times 10 Here, there's a radius for an electron in the ground state, this would be the radius Radius for the electron, so if there's a circle To understand things like quantized energy levels. The Bohr model is useful, is because it allows us Is going this direction, so there is a velocityĪssociated with that electron, so there is velocity Negatively charged electron orbits the nucleus, likeĪ planet around the sun. Picture of the Bohr model of the hydrogen atom. Uncertainty principle to the Bohr model of the hydrogen atom. The position of a particle, the less accurately you know So another way of saying that is, the more accurately you know Uncertainty in the position, you increase the And so, what I'm trying to show you here, is as you decrease the In the position even more, so if I lower that to pointįive, I increase the uncertainty in the momentum, that must go up to eight. Momentum must increase to four, because one times four is equal to four. Uncertainty of the position, so I decrease it to one, so the uncertainty in the

Two is equal to four, so I won't even worry about greater than, I'll just put equal to here. Of two for the position, and let's say you had an uncertainty of two for the momentum. Just extremely simplified, so let's just see if weĬan understand that idea of inversely proportional. Really simple numbers here, just so you can understand that point.

Inversely proportional to each other: if you increase Of the two uncertainties must be greater than orĮqual to some number. It doesn't really matter that much, it just depends on how you define things. Number on the right side, and you might see somethingĪ little bit different in another textbook. So we have a constantĭivided by another constant. And that constant is Planck's Constant: h divided by four pi. Two must be greater than or equal to some constant. Uncertainty in the position, times the uncertainty in the momentum, so Delta P is uncertainty in momentum, the product of these So the uncertainty in the position, so Delta X is the Mathematical description of the uncertainty principle. If you know the momentum really well, you don't know the position. Velocity of that particle, and vice versa. You don't know the momentum, or you don't know the If you know where that particle is in space really well, Uncertainty principle, you can't know the position and momentum of that particle accurately,Īt the same time. Particle, the linear momentum is equal to the Mass times the Velocity. M, moving with Velocity V, the momentum of that Particle, let's say we have a particle here of Mass Heisenberg uncertainty principle is a principle of quantum mechanics. The rule is that the product of the uncertainties of the position and momentum cannot be less than h/(4π) = 5.27286×10⁻³⁵ J∙s (h is the Planck constant). So, it is not MERELY a matter of our not being able to measure with arbitrary precision, but that the particle itself does not HAVE an exact momentum nor an exact location within very specific rules. Likewise, the more set the position becomes the less set the momentum of the particle actually is. Completely apart from any measurement anyone might make, the more set the momentum becomes the less the particle even HAS a set location. This is a limit imposed by nature and it can never be overcome as far as we know with current understanding of nature. Thus, while we can refine instruments to some extent, it is utterly impossible to construct any instrument that would overcome this problem. Likewise, any mechanism by which we might measure the electron's position will affect its momentum, making the momentum less certain. It isn't so much that we cannot measure both momentum (and it is momentum, not velocity) and position of an electron at the same time, but rather there is a limit placed by nature on how precisely we may simultaneously measure both.Īny mechanism by which we might measure the electron's momentum will affect the position, making the position less certain.

Heisenberg uncertainty principle definition