Double Slit Experiment explained! by Jim Al-Khalili

"If you can explain this using common sense and logic, do let me know, because there is a Nobel Prize for you.."

Professor Jim Al-Khalili explains the experiment that reveals the "central mystery of quantum mechanics" - the double slit experiment.

Watch the full lecture here:

Sometimes called the "two-slit" or "Young's" experiment, it demonstrates that matter and energy can display the characteristics of both waves and particles, establishing the principle known as wave-particle duality. Furthermore, it questions the role of the observer in the outcome of events and demonstrates the fundamental limitation of an observer to predict experimental results.

Product links on this page may be affiliate links which means it won't cost you any extra but we may earn a small commission if you decide to purchase through the link.

[eltonmaiyo]

As a game developer, I can tell you its for performance reasons. Why waste processing power rendering particle behavior when there is no observer to output to.

[jimmydanger]

Getting this kind of thing free and recommended for you is definitely a positive of modern life

[IITAspirant]

The people are laughing but just the mere thought of it runs chills down my spine

[penttiranta]

Even if we forget about thousands of other variations of this experiment with all the timetravel, causality breaking consequences, already the fact that a single atom behaves differently going through a single slit and double slit is enough to blow my mind.

[jucklowe]

Seen this experiment described a dozen times, , , , this is about the best one. Bravo for helping my slow brain.

[javiermachin]

I’d say one of the Best double-slit-experiment explanations on the internet.
Fills you with awe and curiosity about this wonderful universe we get to experience.

[normjohnson]

I tried the double slit experiment at home. The wife was not impressed.

[skinfax]

Even though I struggled over this for the last 35 years I never stop to be amazed by this. And this explanation is simply clever AND cheerful. Cheers for that!

[johnvarley]

I hope this analogy helps others to understand.

When people say "observing" changed the result, they do not mean the physical act of watching the experiment - they mean the act of measurement changed the PROPERTY of the thing they were watching.

My analogy; when you take your temperature, the thermometer you use SUCKS heat away from you (consider a metal teaspoon in a cup of tea, the spoon gets hot because heat energy is being transferred from the liquid to the spoon. The tea is actually getting cooler by transferring heat to the spoon) Therefore, the act of using an instrument to measure the temperature of something CHANGES the temperature of that very same thing.

I believe this is the same thing (but of course, probably more complex) but am happy to be corrected. It's a layman's explanation which I feel stands up

[MrWookLoaf]

"According to quantum physics, you cannot "just" observe something. That is, quantum physics recognizes that to make a observation, you must interact with the object you are observing " - Stephen Hawking.

[grahamyodude]

I can explain this easily but I don't want youtube people stealing my Nobel Prize

[AlbinoMutant]

I'm not a physicist, so most of the time I'm just going about my life. But periodically, every few years, I remember this experiment, and I remember there is something about it that I find eerie. I can never remember exactly what it is, so periodically I review the experiment as I just did with this video. And once again, I'm left with the disturbing feeling that something is very wrong with our reality. It's almost like we are not supposed to be aware of certain things, we aren't supposed to be observing them, and when we do, they are altered to keep us from seeing what's really there. If I was running a simulation and didn't want my simulated agents to discover they are in a simulation and start trying to hack their way out, I would implement something to prevent discovery of the fundamental nature of their reality. Every time they tried to look at the substrate of their existence, I would show them something other than the processor they were running on. I don't know about anyone else, but this experiment has caused me to increase my estimate of the probability that we are living in a simulation.

[greggh]

I learned about the double slit experiment in high school and then again in college. I never understood it as well as from your presentation. Thank you.

[daviddahl]

How do you detect an atom without interacting with it?

[simonfintzstein]

I don't know much about science, it wasn't my easiest subject growing up. I am just beginning to learn about quantum physics. Some videos I have watched on this experiment, and I couldn't quite comprehend what was going on. This explains it so very well in an easier to comprehend way. Thank you for this video.

[TheRealestBubby]

This issue is what sparked my everlasting curiosity in physics and quantum mechanics, just to fall down a rabbithole of hundreds of weird and confusing data from experiments that classical laws of physics just cannot explain. there's just so much unknown, and so much to discover and learn. This specific problem in quantum mechanics not only gives plausibility to an observers universe, but also in certain specific scenarios, it fully implicates direct time travel of photons as a normal working part of the universe

[derpy._.josiah]

Bruh I started from a physicist reacting to Attack on Titan and now I’m here😂

[GamesBond.]

First of all, I would like to thank Jim Al Kapone for making this Nobel prize possible. Second, I would like to thank the atoms for being so confusing. I also have a split personality and thats why I can get in their mind. Its not easy to be an atom. You dont even know if you're a particle or a wave. Sometimes you behave like a particle, but sometimes you behave like a wave.

And last but not least, I would like to thank me for being made of these particles waves.

*Waves at atoms. Atoms wave back.*

[kviehdor]

"Quick, the Sims are becoming self-aware!!!!"
Expect a software patch shortly.

[tombrunila]

I have watched many of videos with Jim Al-Khalili, and I can say that he is very good at explaining complex things. Very much like Jacob Bronowski, James Burke and Carl Sagan.