4 ms·

I'd like to read how these problems are solved "in a lab on a benchtop" today!

by acqq 3y ago

funac 3y ago
you can build very good hydrostatic vibration isolators in a home machine shop nowadays; commerical optical tables are /very/ steady
- deleted 3y ago
  [deleted]
dekhn 3y ago
the original experiment is pictured here: https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_exper... what makes it possible to do in a desktop lab course combination of a large number of different innovations. The first is that we know how to make extremely stiff/rigid/strong/flat/thermally stable tables (https://www.thorlabs.com/navigation.cfm?guide_id=41 https://www.thorlabs.com/navigation.cfm?guide_id=41) which can optionally be placed on active vibration-cancelling struts (https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1095 https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=10...). The second is using cage systems for mounting things with everything lined up parallel and centered (https://www.thorlabs.com/navigation.cfm?guide_id=2255 https://www.thorlabs.com/navigation.cfm?guide_id=2255). The third is precise kinematic mounts which make real-time angle tuning a lot easier/more reliable (https://www.thorlabs.com/thorproduct.cfm?partnumber=KM100#ad-image-0 https://www.thorlabs.com/thorproduct.cfm?partnumber=KM100#ad...). The fourth is now we have powerful lasers and LEDs that make generating lots of light all pointing in the right direection easier (https://www.thorlabs.com/thorproduct.cfm?partnumber=CPS532-C2 https://www.thorlabs.com/thorproduct.cfm?partnumber=CPS532-C...). The fifth is that high quality standardized optical parts (mirrors, lenses, etc) are easily available from a wide range of vendors (https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=10649 https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=10...). There are a number of other innovations in material science. but I'd recommend taking a look at Thorlab's Michelson-Morley educational kit. For $3K you get basically everything you need to carry out the experiment: https://www.thorlabs.com/thorproduct.cfm?partnumber=EDU-MINT2 https://www.thorlabs.com/thorproduct.cfm?partnumber=EDU-MINT... plus a nice manual https://www.thorlabs.com/drawings/5d9e11209b7d4536-820A3379-BBFA-E254-33DC018F5C832848/EDU-MINT2-EnglishManual.pdf https://www.thorlabs.com/drawings/5d9e11209b7d4536-820A3379-... that walks you through physical setup and theory behind the experiment (which among other things helped lead to special relativity). if you want more like this, see https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=11630#ad-image-0 https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=11... which is a hardware kit that accompanies an actual optical lab class. The course is online: https://www.thorlabs.com/drawings/5d9e11209b7d4536-820A3379-BBFA-E254-33DC018F5C832848/EDU-OMC1-CourseNotes.pdf https://www.thorlabs.com/drawings/5d9e11209b7d4536-820A3379-... and gives a fairly straightforward introduction to optics. With this, you can easily build a microscope from components or any number of other nifty optical systems. Non-optics people (IE, programmers, etc) with enough time and money can learn how to do real-world optical experiments in their garage (this applies to astronomy too). For example after a significant time/money investment, have started building my own microscopes which use real-time object detection to track tardigrades to do behavior analysis (lest anybody feel imposter syndrome, trust me it took a ton of time and money and even then I'm not quite at the level of a good grad student). It's not my favorite but you can also read https://www.amazon.com/Perfectionists-Precision-Engineers-Created-Modern/dp/0062652567 https://www.amazon.com/Perfectionists-Precision-Engineers-Cr... If you want to truly go down the rabbit hole, https://pearl-hifi.com/06_Lit_Archive/15_Mfrs_Publications/Moore_Tools/Foundations_of_Mechanical_Accuracy.pdf https://pearl-hifi.com/06_Lit_Archive/15_Mfrs_Publications/M...
- acqq 3y ago
  Wonderful answer, thanks! Do you know if the "Michelson-Morley educational kit" is really enough to achieve the accuracy of the original experiment or is it just to make "any" functioning interferometer?
  - dekhn 3y ago
    I'm pretty sure it exceeds the accuracy of the original experiment. I think not being based on a trough of mercury is pretty important as well. But the manual shows several types of interferometers that can be built in lab courses.
    - acqq 3y ago
      Still, I see it is actually called "Michelson Interferometer Educational Kit", not "Michelson–Morley" and the user guide I'm reading (your link gives "The resource you are looking for has been removed", so I've clicked on the "User Guide" on the page instead) also takes care to never directly mention Morley or to suggest that the same experiment can be reproduced with that kit.
      - replygirl 3y ago
        maybe this is their gnu/linux
      - seanhunter 3y ago
        Not my field, but my understanding is it's called the Michelson Interferometer because he designed and built the first version a few years before the famous MM experiment for the purpose of measuring the speed of light. See the diagram on page 3 of his 1881 paper "The relative motion of the Earth and of the luminiferous ether" https://zenodo.org/record/1450060 https://zenodo.org/record/1450060 (note this is before the collab with Morley) Edit to add: I just noticed a fun thing in the conclusion of that paper "In conclusion, I take this opportunity to thank Mr. A. Graham Bell who has provided the means for carrying out this work..."
- 3y ago

I'd like to read how these problems are solved "in a lab on a benchtop" today!

by acqq 3y ago

I'd like to read how these problems are solved "in a lab on a benchtop" today!

you can build very good hydrostatic vibration isolators in a home machine shop nowadays; commerical optical tables are /very/ steady

deleted 3y ago
[deleted]

dekhn 3y ago

the original experiment is pictured here: https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_exper... what makes it possible to do in a desktop lab course combination of a large number of different innovations. The first is that we know how to make extremely stiff/rigid/strong/flat/thermally stable tables (https://www.thorlabs.com/navigation.cfm?guide_id=41 https://www.thorlabs.com/navigation.cfm?guide_id=41) which can optionally be placed on active vibration-cancelling struts (https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1095 https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=10...). The second is using cage systems for mounting things with everything lined up parallel and centered (https://www.thorlabs.com/navigation.cfm?guide_id=2255 https://www.thorlabs.com/navigation.cfm?guide_id=2255). The third is precise kinematic mounts which make real-time angle tuning a lot easier/more reliable (https://www.thorlabs.com/thorproduct.cfm?partnumber=KM100#ad-image-0 https://www.thorlabs.com/thorproduct.cfm?partnumber=KM100#ad...). The fourth is now we have powerful lasers and LEDs that make generating lots of light all pointing in the right direection easier (https://www.thorlabs.com/thorproduct.cfm?partnumber=CPS532-C2 https://www.thorlabs.com/thorproduct.cfm?partnumber=CPS532-C...). The fifth is that high quality standardized optical parts (mirrors, lenses, etc) are easily available from a wide range of vendors (https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=10649 https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=10...). There are a number of other innovations in material science. but I'd recommend taking a look at Thorlab's Michelson-Morley educational kit. For $3K you get basically everything you need to carry out the experiment: https://www.thorlabs.com/thorproduct.cfm?partnumber=EDU-MINT2 https://www.thorlabs.com/thorproduct.cfm?partnumber=EDU-MINT... plus a nice manual https://www.thorlabs.com/drawings/5d9e11209b7d4536-820A3379-BBFA-E254-33DC018F5C832848/EDU-MINT2-EnglishManual.pdf https://www.thorlabs.com/drawings/5d9e11209b7d4536-820A3379-... that walks you through physical setup and theory behind the experiment (which among other things helped lead to special relativity). if you want more like this, see https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=11630#ad-image-0 https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=11... which is a hardware kit that accompanies an actual optical lab class. The course is online: https://www.thorlabs.com/drawings/5d9e11209b7d4536-820A3379-BBFA-E254-33DC018F5C832848/EDU-OMC1-CourseNotes.pdf https://www.thorlabs.com/drawings/5d9e11209b7d4536-820A3379-... and gives a fairly straightforward introduction to optics. With this, you can easily build a microscope from components or any number of other nifty optical systems. Non-optics people (IE, programmers, etc) with enough time and money can learn how to do real-world optical experiments in their garage (this applies to astronomy too). For example after a significant time/money investment, have started building my own microscopes which use real-time object detection to track tardigrades to do behavior analysis (lest anybody feel imposter syndrome, trust me it took a ton of time and money and even then I'm not quite at the level of a good grad student). It's not my favorite but you can also read https://www.amazon.com/Perfectionists-Precision-Engineers-Created-Modern/dp/0062652567 https://www.amazon.com/Perfectionists-Precision-Engineers-Cr... If you want to truly go down the rabbit hole, https://pearl-hifi.com/06_Lit_Archive/15_Mfrs_Publications/Moore_Tools/Foundations_of_Mechanical_Accuracy.pdf https://pearl-hifi.com/06_Lit_Archive/15_Mfrs_Publications/M...

acqq 3y ago
Wonderful answer, thanks! Do you know if the "Michelson-Morley educational kit" is really enough to achieve the accuracy of the original experiment or is it just to make "any" functioning interferometer?
- dekhn 3y ago
  I'm pretty sure it exceeds the accuracy of the original experiment. I think not being based on a trough of mercury is pretty important as well. But the manual shows several types of interferometers that can be built in lab courses.
  - acqq 3y ago
    Still, I see it is actually called "Michelson Interferometer Educational Kit", not "Michelson–Morley" and the user guide I'm reading (your link gives "The resource you are looking for has been removed", so I've clicked on the "User Guide" on the page instead) also takes care to never directly mention Morley or to suggest that the same experiment can be reproduced with that kit.
    - replygirl 3y ago
      maybe this is their gnu/linux
    - seanhunter 3y ago
      Not my field, but my understanding is it's called the Michelson Interferometer because he designed and built the first version a few years before the famous MM experiment for the purpose of measuring the speed of light. See the diagram on page 3 of his 1881 paper "The relative motion of the Earth and of the luminiferous ether" https://zenodo.org/record/1450060 https://zenodo.org/record/1450060 (note this is before the collab with Morley) Edit to add: I just noticed a fun thing in the conclusion of that paper "In conclusion, I take this opportunity to thank Mr. A. Graham Bell who has provided the means for carrying out this work..."
3y ago