How To Make Your Own Double Slit Experiment (Young's) - Easy At-Home Science

Thomas Young's Double Slit Experiment is a science staple for early physics lessons about waves. But did you know that you can recreate it at home with simple, everyday objects? In this Tech Lab, I show you how to use a laser pointer and create your very own apparatus for exploring double slit, single slit, and multi slit diffraction!

*NOTE* - The quantum double slit experiment, where measuring the photons at the slit breaks down the interference into two pools of light cannot be done at home, and was first performed over 100 years after Thomas Young's original experiment.

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Want to learn more about the double slit experiment? Check out the link below:

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~Tech

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Written, Directed, Filmed, Edited and Animated by Tech Adams.
2013, Tech Adams Laboratories

[deathtotruthers]

This is awesome. Took me about 5 minutes to get working! And work it did! Thank you. Blew my son's mind when I explained what was happening. What a cool experiment, and even cooler that you can do it at home with simple materials. I'm thrilled. Thank you!

[MrVaypour]

I'm glad i found you're video! I was moments away from hiring 2 hookers & trying my very own 'double slit experiment'.

[mitchplays]

How to create the observer collapsing the wave function

[TechLaboratories]

Thanks Brian! I was hoping to show people that some pretty cool science can be easily done at home!

[rodnet]

Dude ... only mentioning lasers made my eyes see things less bright ... wow ... it's back to normal now! One of my teachers at the electric engineering school mentioned one of his students using the device you showed to measure wire width during the manufacturing process. Awesome video, man!

[benvinar]

thank you i actually totally understand that experiment now. i read it a few and it just wouldn't sink in

[SumanNath]

OMG this is so mind blowing! Next world shattering experiment would be how to eat and how to potty? Or you just show us how it changes to pattern when observer is turned on.

[BrianTX]

nice work. This is the first DIY double slit experiment I have seen.

[niveyoga]

Your speech at the end was kind of motivational! xD

[cosmicatrophy]

Why have you stopped making videos?? Your stuff is brilliant!

[evilpandakillabzonattkoccu]

I did this a few years ago, just to see if I could....and it melted my mind that I got the same results!

My son got a logic puzzle game with a lazer and some mirrors, targets that light up when hit by the laser...and a type of lens that splits the beam at 90°...

I remembered something I saw earlier.... I took the beam splitter, shot the laser though it at and saw two red dots: one in front, one to the left of me on the wall.

...then, I did the same experiment, but I shot the laser so the first beam would hit a mirror, then return to the splitter lens. I saw three dots now: the first two, and one on my chest due to the mirror.

...I moved the laser so the light on my chest was in line with the dot on the splitter lens and instead of a dot, a bright interference pattern appeared on the right of me on the wall! to enhance the effect, I added a mirror to the left to intercept that light and send it back as well.

the laser was hitting the mirror, so I sent the light back into the splitter lens. I assume that since the mirrors and splitter lens are perfect, the light acted as if it had bounced off more than one mirror. when I forced the beam back into the splitter, it put the beams back since light acts like a particle and a wave, the dots on the left and on my chest (or, in other words, the dots on the mirrors) were dots because it was a single beam. the light being put back through the splitter....interfered with the other beam(s), causing the pattern to occur.

pretty cool

[TheGogmagog]

*NOTE* - The quantum double slit experiment, where measuring the photons at the slit breaks down the interference into two pools of light cannot be done at home.

There is a home version similar to this but with polarized film to 'detect' which photons go through each 'slit'.  Then a third polarized film to randomize them again after the wave was collapsed.

[MagneBugten]

This is really cool stuff, and this is a great way of doing it! I was trying to find a way to do this while taking a crash course in quantum mechanics my freshman year in college (greatest class ever!!).
I used two pieces of .7 and one piece of .5mm pencil lead and stuck them next to each other (thinnest one in the middle) into an eraser. The advantage is that you can do this with a pencil case and a laser pointer, virtually anywhere. And the disadvantage is that it is hard to align the double slit with the laser.

[BullToTheShit]

The only thing potentially interesting to me about the double-slit experiment, is the phenomena that allegedly occurres when you try to "watch" which slit a photon passes through. Then the photons are said to act as particles.

[xADDxDaDealer]

Cool.... but how do i recreate the full experiment where I make it act like a particle by trying to view it?

[JasonAlbalah]

How could you simulate the "Observation Effect", i.e. checking the intensity of either slit?
For single photon sources, this is more intuitive, but for many coherent photons (laser), how would this work?
My goal is to use the laser in a quantum cryptography experiment (observer effect is a hacker)

[DSDMovies]

The flat/curved wave thing explains why the light on my phone didn't work on my ultra low rent, 4 minute prep, attempt to recreate this!

That is not the complete experiment! Do not teach people incomplete things!
This will only add to the problem. Like a blind teaching colors.

The other part of the experiment is to measure which slit the particle-wave enters. Demonstrating what happens when you observe the particle-wave.
Showing wave collapse.

[peoplez]

This isn't the double slit experiment at all. To perform the experiment, you would need to send 1 photon at a time. A laser pointer is always going to have an interference pattern because it's a stream of many photons.

[mmfn]

TechLaboratories, can you elaborate on these "waves" of light? The demos, including yours, show them as parallel lines from the light source going toward the 2 slits then becoming segments of circles spreading from the 2 slits. That is probably what happens in one single horizontal plane intersecting the device/apparatus, but how do they actually look in space? They are not like waves of water because there is nothing going up and down like water waves do (or is it? would a discussion about light polarization help here?) The best way I can try to imagine them is like cylinders segments with the height of the slit(s) but then the wave aspect would be a modulation in density/intensity(?) of the light on the direction(s) of the propagation, like layers of cylinders alternating between brighter and darker resulting in bright lines where 2 bright cylinder intersect (on a line) and dark lines where 2 dark cylinders intersect. So that would rather be comparable with waves of sound than waves of water. Can you shed some light on this matter?