Snell's law of Refraction
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- เผยแพร่เมื่อ 28 ก.ย. 2024
- 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).
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!
i dont
I don't have
So true.🥰🤩
Why can't we use a rectangular glass disc other than a semi circular glass disc in that experiment? please reply fast
@@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.
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.
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?
This experiment was very comprehensive. It helped me a lot in understanding the refraction of light
stfu nerd
my homework is literally a drawn version of this that was just confusing. Thank you for making it cool and visual!
My mind is blown. I only read about it and it was amazing but actually seeing it happen, blows my mind!
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.
Tq ~
Tq so much sir ❤🙏🙏
sir why there is no total internal reflection even when all conditions for it are fulfilled ?
@@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
@@scarlett4678a mi nunca me dicen esto 😞
@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).
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.
I loved this video, can you upload it to my humble TH-cam channel?
U don't know how this helped me a lot. Thanks a bunch sir
Thank you, u r helping me for my SPM after 13 years 🙏
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.
This is a very clear demonstration of snell's law. The demonstration itself is the education. Thank you!
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.
what is the realstionship between the angle of incident and the angle of reflection
What makes or forces the light to speed up again when it leaves the block?
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.
Awesome teacher Mr roberts thank you to my support by tutoring science
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?
excellent. could you explain the angle of soil and air please?
Love from india sir❤️❤️❤️❤️
@junior1984able It works with any transparent object (regardless of shape or material) - light even refracts when it leaves water, which is why it is difficult to judge how deep a swimming pool is.
Can you tell me how a projectile traveling 2500 miles an hour will do the same thing shot in a straight line?
So how was Total Internal Refraction diffrent from Snells law? I still haven't completed the chapter yet, so lil confusion
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.
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
Haa miku Aina exams levuga miru happy ne ga
@@muskanshaik5360 no sir I am 2021 batch
It just makes measuring the angles a lot easier.
thank you sir for uploading this videos they really made physics easy
@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.
SUUPER
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
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.
@@QuantumBoffin thank you so much!
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.
If you know or not sir a screenshot has been taken from your video and has been published in Andhra pradesh state physical science text book 10 class and many batches of students are learning it you can just get the pdf of that text book on Google and on pg 49 of our textbook do check it
Hi. Thank you for letting me know. There's no harm done by this, but it would have been appropriate for the publishers to attribute the images to their sources. It's nice to see, though, how widely used my experimental videos now are.
@@davidselecandtech4732 yeah thats what I wanna make you feel proud and check it
@@davidselecandtech4732 i meant quantum boffin not you
@@apricity192 Apologies: I was logged into the wrong TH-cam account when I replied to your post.
@@QuantumBoffin did u check it
why do you have to use the semi-circular block-like object?
@go2ec4 that is because the refractive index of ur medium is different from the one that is used in the vid.
what does it look like when you enter through the curve?
Great demonstration thank you
Tir
Piscies
thank YOU
Hello,does the glass block have to be circular shaped for it to work??
youtube is good for education^^
What is the object in which we see in the video
Sir this was uploded before 13years but iam watching it in 2023😮😇
Same
@griffallstar I swear it's meant to be 42 degrees, but this one only started showing strongly at 70 ?
what laser do you use?
Yeah, idk?
@Bushater2000 thank you, one quetion i had in mind also,where could I buy a light projector like the one you have??
What Plano convex optical piece you have used in this experiment please give it's value
shouldn't light be refracted 2 times one when it enters and other when it's exits the slab?
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
Utkarsh Aggarwal chagantipravachanamulu
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.
but if you change the shape to a triangle or rectangle, you will be able to see twice refraction
by principle law of Einstein
thanku so much for your efforts
man I love you channel
How you are making it
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...
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.
@@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?
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.
thanks for your excellent explanation
3 min here
And 3 classes there
That's called difference
Awesome 👍
Is the material Perspex, acrylic or glass?
Naman Chawla You can use any of them (although I've never tried using acrylic). The block I used on this occasion was glass.
This is the most sinister video I’ve watched about physics
yes
where can i buy those half circle glass bowls ??
in a shop
Amazing respresntation in video
What is the critical angle of air
Thats like asking what is the temperature of purple in Fahrenheit
The net refraction is 18.5" degrees
WOW. beautiful experiment. simple and straight forward. THANK YOU
what is up with this degrees
This is very usefull, straight to the point, so we understand it easir
Why was some of the light partially reflected
+Ahmed Medhat It's probably due to:
1) As the incidence beam gets closer and closer to the critical angle, more and more of internal reflection is occurring. That's why the reflected light get brighter and brighter as he increase the incidence angle. Once the incidence beam exceed the critical angle, total internal reflection will occur. This mean all light get reflected.
2) They may also be imperfections in the glass blocks due to quality of the glass (and refractive index).
3) Then there is 2 surfaces that the light hits. First is the bottom flat surface of the glass block, and some light gets reflected back while the rest some makes through the glass block. Then the light that made through the glass block hits the top curved surface of the glass block. And some light from there gets reflected back and some gets out of the glass block. So there maybe multiple refraction, reflections and internal reflections, which might explain why there are so many light beams produced.
Ignore Ahmed's answer below! This is NOT an experiment on Total Internal Reflection as that ONLY occurs in going from a dense medium to a less dense medium.
The answer to your question is that when light goes from a less dense medium to a dense medium there is always SOME light which get reflected but the ratio of the light reflected to that which continues on by refraction varies. This ratio varies with angle.
Therefore, as the angle of incidence increases, the reflected wave becomes more noticeable.
It is NOTHING to do with total internal reflection.
Rob Keeping I did not answer anything, I;m the poster of the question but thanks anyway.
I want to know that what is the use of this, i mean what can we gain with this activity, please reply me☺️☺️
One of the most common uses of refraction is in lenses which can be used to bend and focus light. This experiment helps us to understand how this happens. Lenses have lots of uses including spectacles, telescopes, cameras and the human eye.
@@QuantumBoffin thanks for yourexplaination
how did you get that laser plz reply
it is from a ray box
Ur explanation is superb sir. It understand clearly. ☺☺👍👍
Wonderful explanations
This is the picture in our physics textbook of class 9th state...they used your video😢
can someone comment down the whole procedure, aim, apparatus etc, for the above experiment
Don't u have a text book or a guide
@@muskanshaik5360 lmao I passed my exams.
Define snell's law..?
SNEL YA LATER
n*sin(angle in) = n* sin(angle out)
n1*sin(v1)=n2*sin(v2) where n1 and n2 is the medium in which the light traveled in, v1 being the angle of approach and v2 being the angle of refraction.
As every schoolboy will (ought to) know, light follows the path of 'least time' (the Fermat principle). To do so when entering a medium in which it changes speed, it must 'turn' by the exact amount observed in the experiment.
Destilation to cleaning hollow ground
But you should have used a rectangular glass
Priyanshu Soni Why? That might be the traditional way but using a semi-circular Block produces results far more easily and with greater accuracy.
he did it the other way around....can u do the exp to determine critical angle?
Science test?
Thank You
good it's very helpful thanx a lot for upload
I love Optics.
😱😱😱 OMG so helpful
very good
nice video
It's amazing
We are the optical lens factory, looking forward to cooperation opportunities
i want 9th class refraction of light at plane surfaces they are showing 10th class chapter
Are you talking about the order? In this video, it's first order. There is no analysis of 2', 3', 4', etc. 9' would be impressive. I wanna see a rainbow with 8 twins.
In 9th class this chapter is not present
thank u, it cleared my concept..
...
Nyc
Amazing....thx...alot
Tq
Super
Foartee phiove degrees.
Brights
Snell's law to 3rd graders???? Good luck
0-0
says better
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thanks, but no thanks
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.
says better
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
الي جاي من حصة الفيزياء ليك
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?
WOWOW! This is amazeballs
daca va uitați doamna nu stiu sa fac
Please tell me some error in this expiremet😬