15 posts tagged “quantum”
The subatomic realm is uncertain as to where things are. We cannot know where something is. It follows that we don't know where something has been; nor where it is going. All we can work with are tunnels of probability.
Transcript: http://www.davidcolarusso.com/edblog/?p=33#more-33
This video is an adaptation of an earlier piece of mine--Perspective on quantum mechanical tunneling. That film, however, was designed for a unique audience, and I felt its overall length was limiting its appeal here. So I've repackaged it as one of my weekly postings. I Hope you enjoy.
People have been asking for the math. So here it is. The Sun's core temp is ~13.6 MK. For hydrogen nuclei the Coulomb barrier is roughly 0.1 MeV. This corresponds to a temperature in excess of 1 GK! Luckily, tunneling and the distribution of speeds among nuclei lower the actual temperature required. So without tunneling even the Sun's core isn't hot enough for fusion. To see most of this worked through, check out this link:
http://burro.cwru.edu/Academics/Astr221/StarPhys/coulomb.html
for a less mathematical explanation, try:
http://en.wikipedia.org/wiki/Nuclear_fusion#Requirements
The Tabletop Explainer is a quasi-weekly series answering science questions and presenting brief lessons and ideas for teachers and students. If you have any comments, move the discussion to my blog, "On Education" http://www.davidcolarusso.com/edblog/
In the atomic world, the only way to find out where an atom is to measure it. Before measuring, that atom is everywhere. Observation creates the universe. Oxford University's David Deutsch says what is true of the atomic level is universally applicable. There are parallel universes--multiverses--where every possibility exists. Others think "philosophical speculation" is a waste of time. Shut up and measure; that's all.
Serialjunkie says: God loves to play tricks on scientists. Professor Al-Khalili reflects on quantum mechanics' measurement problem.
Ross Rhodes guides us to the limit of the Shrine of Objectivity. This cult meets its match in the quantum realm (the very very very tiny). The Double Slit Experiment is the arena where objectivity meets its tragic end. The First Person Singular, for the first time in science's history dethrones the reigning monarch, objectivity, and takes Its rightful place as the Kosmos's foundation. But first, let's review motion in media, waves; their radiating movement; wave interference; wave patterns. Alas, the sound on these videos is poor; a small price to pay considering...
Illustrated presentation of quantum mechanics & the double slit experiment. Wave-particle duality meets information theory. And it's fun!
In Part 2 we look at particles and the nature of light. Particles are tiny bits of matter. They rest unless acted upon by other particles. They stay in motion unless acted upon by other particles. When they collide, they bounce off each other. Is light a wave or a particle. Newton says a particle--maybe. Hook says a wave--maybe. Thomas Young wants to decide and the Double Slit Experiment is born in 1801.
When particles are smashed the smallest unit one arrives at is the quark. Collections of quarks, atoms, molecules can be held in the hand, have temperatures taken and weighed. How do particles go through slits?
Now we fire particles one at a time through the double slit. We notice the photographic plate at the back collecting a wave pattern. What is going on?
Now we count particles one by one going through the slits. We have detectors at the slits telling us. Where the particles hit the wall, a particle formation forms. We then take the detectors away and thereby are left clueless as to where the particles go through. Now what's this? There is now a wave pattern again!
If a particle goes through a slit heading for the back wall does it hit the wall if no one is looking?
No.
Observation creates what we see at the back wall.
Illustrated presentation of quantum mechanics & the double slit experiment. Wave-particle duality meets information theory. And it's fun!
Illustrated presentation of quantum mechanics & the double slit experiment. Wave-particle duality meets information theory. And it's fun! (more)
