Snell's law of Refraction

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14 жыл бұрын

An experimental demonstration of Snell's law of Refraction. Light is shone through a glass block at various angles. A calibrated paper template allows the angles of incidence and refraction to be determined. (The angle of incidence is also spoken out during the experiment).

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@QuantumBoffin 13 жыл бұрын

When light enters a denser substance, such as glass, it slows down. It's this slowing down that makes the angle of refraction less than the angle of incidence. When the light leaves the block it speeds up again - under these circumstances the opposite is true, although you can't see that in this video.

@scarlett4678 3 жыл бұрын

Tq ~

@Sarkar.editsz 3 жыл бұрын

Tq so much sir ❤🙏🙏

@sol90981 2 жыл бұрын

sir why there is no total internal reflection even when all conditions for it are fulfilled ?

@youtubekalua100yearsago4 2 жыл бұрын

@@sol90981 no, it has total internal reflection . Watch at 75 degrees and above. You will clearly see that there will be a bending of light on the side from where it incident. So here total internal reflection has done

@rogergperson Ай бұрын

@@scarlett4678a mi nunca me dicen esto 😞

@lafeo0077 7 жыл бұрын

I love straight forward, channels, which don't have gimmicky science and in based for just providing the information which you precisely need at that point. I love your channel!

@isevseva9616 5 жыл бұрын

i dont

@jaswanthjaswanth4736 3 жыл бұрын

I don't have

@thepianoguy6027 3 жыл бұрын

So true.🥰🤩

@joinmyjourneytodoctor4866 3 жыл бұрын

Why can't we use a rectangular glass disc other than a semi circular glass disc in that experiment? please reply fast

@noeljonsson3578 3 жыл бұрын

@@joinmyjourneytodoctor4866 I would assume to only show the changes from entry. As you notice the exit of the light isn’t at an angle. If he were to use a rectangle the exit would have reversed the effect from the entry.

@QuantumBoffin 14 жыл бұрын

I have one of my A level students to thank for this method - he did a project on improving the accuracy of the experiment. The method is straightforward (takes a class about 10 to 15 minutes to do) and the results you get are excellent.

@xander1756 4 жыл бұрын

I take it the glass block is uniform, ie, same density or consistency of material throughout, thus the variation of output angles is solely due to the change of the incoming angle to the block?

@bhaskarbiswas3763 4 жыл бұрын

This experiment was very comprehensive. It helped me a lot in understanding the refraction of light

@izclan9814 3 жыл бұрын

stfu nerd

@QuantumBoffin 13 жыл бұрын

@HKNajjar this demonstration does not show total internal reflection - I plan to add another one that does at some stage. If you look at the ray you will see it always leaves the block travelling along the normal: total internal reflection occurs when this angle become large (about 43 degrees for glass, depending on the grade of glass).

@priscilamorales6997 3 жыл бұрын

my homework is literally a drawn version of this that was just confusing. Thank you for making it cool and visual!

@arna664 Жыл бұрын

U don't know how this helped me a lot. Thanks a bunch sir

@QuantumBoffin 14 жыл бұрын

The aim of a video is to demonstrate an experiment concerning refraction, allowing measurements to be taken: it is intended to be used in a classroom with the assistance of a teacher who could then explain it to you. If you want to understand refraction there are other videos out there that will explain it to you.

@QuantumBoffin 14 жыл бұрын

You can do the experiment using any glass or Perspex block. The semi-circular block, however, makes it much easier to read the angle of refraction.

@nosborlopesTP Жыл бұрын

I loved this video, can you upload it to my humble KZfaq channel?

@akus8844 4 жыл бұрын

My mind is blown. I only read about it and it was amazing but actually seeing it happen, blows my mind!

@wbillich 12 жыл бұрын

This is a very clear demonstration of snell's law. The demonstration itself is the education. Thank you!

@onetwo7284 Жыл бұрын

Thank you, u r helping me for my SPM after 13 years 🙏

@QuantumBoffin 12 жыл бұрын

The ray box and semi-circular block are standard items available from more science education retailers - you should be able to find such retailers on line. The template I drew by hand.

@baraskparas 3 жыл бұрын

Great demonstration. Simple and to the point. Thanks.

@strhwaberry 11 жыл бұрын

This makes a lot of sense! Thank you :D But may I ask, where is the emergent ray? :o or is there no emergent ray?

@junior1984able 13 жыл бұрын

@Bushater2000 thank you, one quetion i had in mind also,where could I buy a light projector like the one you have??

@gummyberrygaming9676 2 жыл бұрын

Thank you so much for this, sir! This helped me out with my curiosity

@angeliepaul9447 5 жыл бұрын

What Plano convex optical piece you have used in this experiment please give it's value

@madsvraa2600 4 жыл бұрын

WOWOW! This is amazeballs

@odal6770 3 жыл бұрын

If we draw the tangent to each of the exterior markings, and then draw a perpendicular line all the way down, will this line fall each time together with the beam? Did you try it?

@aman_singh__ 3 жыл бұрын

At first I thought why isn't it bending at the other end then soon I realized there's a reason for that surface to be circular so that light always falls perpendicular and it come out as a straight line

@vandhana717 Жыл бұрын

Sir this was uploded before 13years but iam watching it in 2023😮😇

@Ps5lover811 Жыл бұрын

Same

@medikondaanuradha2010 2 жыл бұрын

Tq so much for providing this experiment in a simple way

@ThePaulTM 3 ай бұрын

Thank You! Quad Step Ball rings can be concentric and each ring group as it increases in diameter in a 5 stack can show a 4 colour sequence at a different slope angle. Its a good chance that this is where the refraction angle comes from as it passes through different chemical ring structures.

@wiktoriaheinz9244 5 жыл бұрын

Very instructive, thank you!

@drakekay6577 4 жыл бұрын

what does it look like when you enter through the curve?

@murthymurty8398 4 жыл бұрын

thank you sir for uploading this videos they really made physics easy

@pAJ-xd6bb 4 жыл бұрын

what is the realstionship between the angle of incident and the angle of reflection

@Nareshkumar..387 3 жыл бұрын

😱😱😱Omg before 11 years video with nice understand concept😱😱😱

@pixelmatrix_ 7 жыл бұрын

man I love you channel

@gtube6913 11 ай бұрын

What makes or forces the light to speed up again when it leaves the block?

@QuantumBoffin 11 ай бұрын

Great question! Usually we assume that a force is needed to change the speed to an object (ie to slow it down or speed it up) as this is what we’re used to with everyday objects. Waves, however, do not involve the motion of physical matter (just energy) and so don’t obey the same laws as physical matter. The question we should be asking is not why the wave speeds up again, but why it slowed down in the first place. Once you understand that then it is easier to appreciate why the waves returns to its previous speed once you’ve removed the thing that was slowing it down to begin with. The answer, I'm afraid, is quite technical: the material that the wave travels through vibrates in response to the wave, and creates its own wave as a result. This wave pages behind the original one and, when added to it, produces the effect of a new waves travelling at a slower speed.

@QuantumBoffin 13 жыл бұрын

Refraction occurs with any glass block but using a semi-circular block makes it a lot easier to measure the angle of refraction.

@ro-hanbiswas2654 3 жыл бұрын

Awesome teacher Mr roberts thank you to my support by tutoring science

@marjanmolaie6992 7 жыл бұрын

Can you get what's he's using online?

@junior1984able 13 жыл бұрын

Hello,does the glass block have to be circular shaped for it to work??

@fardinheidari5787 2 жыл бұрын

excellent. how can i find the angle of light through soil to air?

@raghavrana9 3 жыл бұрын

Love from india sir❤️❤️❤️❤️

@QuantumBoffin 13 жыл бұрын

The light leaves the block at 90 degrees to the surface (i.e. along the normal line). When light enters of leaves a block stright on in this way it does not change direction: the light only bends if it hits the edge of the block at an angle.

@ytcobra7352 2 жыл бұрын

What type of light did you have used

@MegaMakeupify 12 жыл бұрын

Where did you get the sheet of paper with all the angles?

@captainvenom7252 2 жыл бұрын

3 min here And 3 classes there That's called difference

@vritrakanha 8 ай бұрын

So how was Total Internal Refraction diffrent from Snells law? I still haven't completed the chapter yet, so lil confusion

@QuantumBoffin 8 ай бұрын

They are both very similar, but if you watch the videos again you’ll notice that refraction is where the light passes through the glass block, whereas with total internal reflection the light is reflected inside the glass.

@nasreen4605 7 жыл бұрын

thanks for your excellent explanation

@nothingnothing4857 2 жыл бұрын

What if you put below that cylinder a whole cylinder ? And do double lights on top of half a quarter cylinder ? Stack pile up the degrees.

@tunesmith795 5 жыл бұрын

Excellent representation.

@shoopdawhoop7826 8 жыл бұрын

Why does the light only refract one time? Shouldnt it refract twice?? (Once when it enters, again when it exits)

@dylanpatel9295 8 жыл бұрын

I believe this is the use of a semi circular prism. It refracts once when it enters and hits the end of the curve with perpendicularly making a straight line.

@jamesy1955 4 жыл бұрын

I calculated the refractive index at 1.49. Is that about right? 🤔

@mrtictac94 13 жыл бұрын

@griffallstar I swear it's meant to be 42 degrees, but this one only started showing strongly at 70 ?

@JohnCBriggs 14 жыл бұрын

Nicely done. Thanks for sharing.

@junior1984able 13 жыл бұрын

@junior1984able how much would one ray box cost?

@bharti_kumari1633 3 жыл бұрын

What is the object in which we see in the video

@fardinheidari5787 2 жыл бұрын

excellent. could you explain the angle of soil and air please?

@yaminiraomenneni9323 3 жыл бұрын

VERY NICE IT IS VERY HELP FULL FOR ONLINE CLASSES

@heypeopleitsmatt 11 жыл бұрын

sorry can i get some help, i'm doing a physics experiment for my class where can i find the semi circular container similar to the one in the video ?

@beerus553 4 жыл бұрын

do you still need some help?

@raiedahmednishat8883 6 жыл бұрын

Dis is just wat I wanted thanks

@rainprettybb 12 жыл бұрын

youtube is good for education^^

@HKNajjar 13 жыл бұрын

How come total reflection does not occur until something very close to 90 deg? In another video there seemed to be total reflection. Maybe it's because this is a white beam, that one was red?

@utkarshaggarwal1631 7 жыл бұрын

shouldn't light be refracted 2 times one when it enters and other when it's exits the slab?

@dalehobart6174 7 жыл бұрын

There is no angle of refraction as it hits the circular side because it is along the normal line. A change of angle (bending) only takes place if there an incident angle other than zero degrees from the normal

@santhichennuru986 7 жыл бұрын

Utkarsh Aggarwal chagantipravachanamulu

@chrisqin12 7 жыл бұрын

What Dale said is true. If the half circle is replaced with a circle, there will be no bend of the incident light at any angle. This can be explained by Dale's words as well.

@chrisqin12 7 жыл бұрын

but if you change the shape to a triangle or rectangle, you will be able to see twice refraction

@owaisrather6943 6 жыл бұрын

by principle law of Einstein

@dimi194 14 жыл бұрын

why do you have to use the semi-circular block-like object?

@sachinpaleja9546 6 жыл бұрын

what laser do you use?

@PhrostiX 5 жыл бұрын

Yeah, idk?

@mariyumasim4487 Жыл бұрын

Can someone please explain as to why the light didn't bend away from the normal when it was leaving the glass(why the emergent ray was straight) like it normally does it in a ray diagram

@QuantumBoffin Жыл бұрын

The incident ray is travelling along the normal (it hits the boundary straight on), and so it continues to do so once is passes through the boundary.

@mariyumasim4487 Жыл бұрын

@@QuantumBoffin thank you so much!

@user-hi7xg3lh4g Жыл бұрын

Please tell me some error in this expiremet😬

@k.prasad5345 6 жыл бұрын

Wonderful explanations

@Sara-gw5hv 2 жыл бұрын

This is so cool I just learnt this at school They didn't do the practical because our lasers in our school were broken Well light is weird

@IchBinKarotte Жыл бұрын

@abhimanyuraj7757 2 жыл бұрын

thanku so much for your efforts

@anastasiapilorge8743 9 жыл бұрын

WOW. beautiful experiment. simple and straight forward. THANK YOU

@QuantumBoffin 13 жыл бұрын

It just makes measuring the angles a lot easier.

@senseifarozan47 11 жыл бұрын

good it's very helpful thanx a lot for upload

@QuantumBoffin 12 жыл бұрын

@MegaMakeupify The sheet of paper was hand drawn, but it does the job. There are some commercial versions available (PASCo make one, I believe) but, alternatively, you could just photocopy (and enlarge) a protractor.

@purshothamthyagaraj9218 5 жыл бұрын

SUUPER

@Sapient1989 13 жыл бұрын

@go2ec4 that is because the refractive index of ur medium is different from the one that is used in the vid.

@muthuprasad8281 4 жыл бұрын

Sir I am studying state syllabus in andhra Pradesh state we have this experiment for that experiment they gave your experimental set up as picture amazing sir

@muskanshaik5360 3 жыл бұрын

Haa miku Aina exams levuga miru happy ne ga

@muthuprasad8281 3 жыл бұрын

@@muskanshaik5360 no sir I am 2021 batch

@suryanarayana4620 7 жыл бұрын

I liked Snell's law video

@sativayejay 5 жыл бұрын

where can i buy those half circle glass bowls ??

@isevseva9616 5 жыл бұрын

in a shop

@namanchawla5512 5 жыл бұрын

Is the material Perspex, acrylic or glass?

@QuantumBoffin 5 жыл бұрын

Naman Chawla You can use any of them (although I've never tried using acrylic). The block I used on this occasion was glass.

@envynation8126 10 жыл бұрын

Great demonstration thank you

@arshnadeem12b29 6 жыл бұрын

Tir

@vanisampath4343 6 жыл бұрын

Piscies

@isevseva9616 5 жыл бұрын

thank YOU

@go2ec4 13 жыл бұрын

ive tried this but the results are not the same ,when i set the light on an angle of 10 the reflected light' angle was 11

@madhusoni447 5 жыл бұрын

what was the critical angle? was it at 55 degrees?

@QuantumBoffin 5 жыл бұрын

This experiment doesn't actually show the critical angle. I have another video on a Total Internal Reflection that shows that.

@nitu.-_ 4 жыл бұрын

Amazing respresntation in video

@4mahr 3 жыл бұрын

الي جاي من حصة الفيزياء ليك

@s__hstatusworld2788 2 жыл бұрын

How you are making it

@benjavides 7 жыл бұрын

Hi! Does anyone knows a software to calculate the amount radiation due to refracted light passing through a transluscent solid considering light absortion?

@meghna6504 6 жыл бұрын

see its really simple.......simply go to google and find out,

@TypicalLuffy 2 жыл бұрын

i know one

@TypicalLuffy 2 жыл бұрын

calculator

@dilipsinhrathod6693 6 жыл бұрын

Thank You

@sidatouch 6 жыл бұрын

What do u call that source of light he is using?

@isaackarwemera4076 6 жыл бұрын

Sid Sauleh A ray box. It is a box with a light bulb inside it.

@i8anapplemac 6 жыл бұрын

This is the most sinister video I’ve watched about physics

@TypicalLuffy 2 жыл бұрын

yes

@Max-lt3wo 2 күн бұрын

It's wierd when people say there's no critical angle from air into glass. When it's clear that there is a critical angle here.

@ashengamage2134 6 жыл бұрын

It's amazing

@rahulalexrahulalex3689 6 жыл бұрын

Good explanation

@QuantumBoffin 14 жыл бұрын

I just used a 24W 12V bulb, along with a narrow slit in front of it. Not sure a standard laser pen would work that well - the beam is too narrow - you might not get a very good trace.

@isaacsamuel9520 3 жыл бұрын

Why is the emergent ray not parallel to the initial ray??? Shouldn't it emergent ray be laterally shifted and parallel to the initial ray?? Please respond, as this is quite perplexing for me...

@QuantumBoffin 3 жыл бұрын

This is a common point of confusion. The ray will only emerge parallel though if the glass block has parallel sides (such as with a rectangular block). For other shapes (e.g. semi-circular, prisms and lenses) he light will change direction.

@isaacsamuel9520 3 жыл бұрын

@@QuantumBoffin Thank you for responding!! Also, is there like a general method or formula to find that change in angle when light comes back from glass to air?? One that is valid for all shapes?

@QuantumBoffin 3 жыл бұрын

Isaac Samuel Yes. It's known as Snell's law. (The point of this experiment is to produce data to test Snell’s law). Snell’s law related the Sines of the angles at which the light enters and leaves the bock.

@ayushmishra7765 3 жыл бұрын

Awesome 👍

@sahibzadaaafaqahmad2781 4 жыл бұрын

That makes a lot of sense now how internal reflection works....

@fazedoe7248 8 жыл бұрын

what is up with this degrees

@vaishalraj416 6 жыл бұрын

I also wanted to see light day passing from tender medium to rarer medium . but thank you . great demonstration.

@vaishalraj416 6 жыл бұрын

sorry denser medium to rarer medium

@mohammedjafferali693 7 жыл бұрын

how did you get that laser plz reply

@joshuaphilip7253 7 жыл бұрын

it is from a ray box

@YummyYummy-oc4nz 8 жыл бұрын

Amazing....thx...alot

@QuantumBoffin 14 жыл бұрын

Most educational science suppliers stock such items. Try doing a search for "Pasco" - they're an american company (but have stockists worldwide) and produce some excellent (but pricey) equipment. They also produce a template (better quality than my hand drawn one) to measure angles with.