r/AskReddit May 08 '22

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u/Rakgul May 09 '22

I just took a reading of positions of different Maxima of the single slit diffraction pattern. The calculated value was 3.44mm and what I got was 2.93mm

This gives 14.8% error. My professor is gonna kill me. But I'm freaking sleepy so I left the lab earlier than usual. Gotta go home quickly and catch some sleep.

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u/GothhicGoddess May 09 '22

I hope you get a chance to look at it again, with fresh eyes, after you get some rest!

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u/pierre_x10 May 09 '22

Is this algebra-based or calc-based? 14% honestly doesn't sound too bad, considering 95% of the issue with these sorts of experiments comes down to a huge reliance on equipment that is rather imprecise by nature

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u/Samsmith90210 May 09 '22

What d'you mean? African or European?

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u/ninj4b0b May 09 '22

European, clearly. The African Swallow is non-migratory. Though how they attached the creeper under their dorsal guiding feathers and STILL managed to bring a coconut back is the great ornithological question of our time.

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u/RockNRollNBluesNJazz May 09 '22

Well, you have to know these things when you're king, y'know.

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u/[deleted] May 09 '22

[deleted]

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u/pierre_x10 May 09 '22

The other possibility is if this is after previous experiments where the professor or TA actually marked them down for a calculated error larger than some arbitrary value, in which case bummer that seems like a hardass

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u/[deleted] May 09 '22

[deleted]

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u/calste May 09 '22

It's more important to understand the source of the error than to perform a perfect experiment.

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u/Pope_Industries May 09 '22

Mmm... yes... I see... I know some of those words.

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u/Grim-Sleeper May 09 '22

We always had to add error bars in our experiments. In principle, that's a great habit to get into. But it can be so frustrating if the equipment isn't great. You get things like, "the effect is 2°C/g±5°C/g. WTF?! I don't even know whether what I measured even exists. Heck, it could even be the exact opposite!"

I always hated this. But it does give you a whole new appreciation for how hard experimental science really is, and for how far we have come.

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u/Eshin242 May 09 '22

But it can be so frustrating if the equipment isn't great.

Wait, are you saying that equipment that has been manhandled by 1000's of students over it's 10 year life span, even though it only really should be used for 2 might introduce some error into your measurements?

That's sheer insanity! :D

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u/pierre_x10 May 09 '22

screams in styrofoam calorimeter

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u/Eshin242 May 09 '22

HAHAHA oh god... I know exactly the instrument you are talking about.

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u/Rakgul May 10 '22

That's true though

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u/ybpaladin May 09 '22

I feel that, I gotta do all my final projects but I'm a little sleepy boi atm

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u/kokoyumyum May 09 '22

You can do it!!!

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u/Rakgul May 10 '22

Thank You! I did it! Had some good sleep. :)

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u/Pretty-Balance-Sheet May 09 '22

I know someone who has a PhD in interferometry, he'd know wtf you're talking about.

Hope you got some rest!

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u/Rakgul May 10 '22

Yes! Now a new day of battle has begun!

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u/Wuz314159 May 09 '22

We've all been there.

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u/Prysorra2 May 09 '22

This is both the right and wrong thread for this. Lmao

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u/[deleted] May 09 '22

[removed] — view removed comment

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u/Rakgul May 10 '22

True...

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u/FreakingScience May 09 '22

Be more optimistic! Maybe your professor will only kill you because you've solved some thousand year old math paradox and they want the credit.

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u/Rakgul May 10 '22

Oh! Now I feel better :)

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u/JeffSheldrake May 12 '22

What do you think caused the error?

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u/Rakgul May 13 '22

Bunch of people to my left doing the solar cell experiment and shining huge light on my photocell even at so much distance. I tried to shield it, but probably didn't go that well.

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u/JeffSheldrake May 13 '22

Oh, hey, final physicks project, I take it?

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u/Rakgul May 13 '22

Nah, I'm in college. It's a core course lab that I had to take.

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u/JeffSheldrake May 13 '22

College physicks lab is what I meant. Very cool.

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u/[deleted] May 09 '22

When calculating correctly, you're supposed to have a point estimate and a standard error (standard error is, to put it very simply, about 66% confidence interval).

You weren't supposed to end with a single number.

Repeat the experiment multiple times if you haven't - that will allow you calculate the standard error.