Shadowing Practice: This Video Is 2D And 3D Simultaneously: the Pulfrich Effect - Learn English Speaking with Video
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40 sentences
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1
This video is in 3D.
2
Really, it is.
3
If you get a pair of sunglasses and you just cover your right eye, you should see a 3D effect.
4
I mean, assuming both your eyes work, obviously.
5
Sorry, if they don't.
6
The effect will work best on a big, bright screen, in a bright room, wearing dark sunglasses, and if your device is playing this at a high frame rate.
7
If you're just kind of lying in bed, squinting and holding your phone out, it probably won't work.
8
Also, you'd look ridiculous.
9
Normal 3D video works by sending a different picture to each eye.
10
Those two simultaneous images, one for the left eye, one for the right, are called a stereo pair, and they simulate what you would see with two eyes.
11
So, you display two images on the same screen at the same time, and then you use filters to show only one to each eye.
12
And that might be using a red and blue image in coloured filters, or weird tech glasses where each lens goes opaque 60 times a second, or, in a modern cinema,
13
glasses that filter using polarized light.
14
But because there have to be two separate images on the same screen at the same time, for anyone not wearing those glasses, it's a confusing mess.
15
But this video here works as a normal 2D video as well, at the same time, and the reason is something called the Pulfric effect,
16
named after Karl Pulfric, the German optometrist who first documented it in the early 20th century.
17
Your eyes and brain take a little bit longer to process dark images than light ones.
18
Now exactly how long depends on the relative brightness of the images, but usually roughly around the length of one frame of video,
19
which is pretty useful for something first noted nearly a century ago.
20
If you put dark sunglasses over your right eye, then the image from that eye will get delayed by about one frame on its way through your brain.
21
So you end up seeing two different images, one frame apart, in time.
22
But that's not enough to create a stereo pair on its own.
23
The other ingredient is the bizarre, nausea -inducing, moving camera.
24
Because that camera has constantly been in motion, your right eye has been lagging behind by about one frame, just as if there was a second camera just to the right of that one,
25
giving you a separate stereo image to your right eye.
26
Now, that's a stereo pair, so if we stop the camera rotating, the effect disappears and everyone can take a breath.
27
That also works by moving the objects in the frame.
28
That's why, earlier, the cutaways I used had constantly moving backgrounds.
29
And sure, it's not perfect 3D, but your brain fills in the gaps.
30
The Pulp Rik effect works well enough that it's been used for TV shows occasionally and for a couple of video games.
31
In the 90s, the BBC had a special series of 3D shows for a charity telethon, including one of the worst Doctor Who productions ever made.
32
Who's that terrible woman?
33
But if you look at it, in every shot, something in the foreground moves left to right, and something in the background moves right to left, constantly.
34
So because every camera shot has to be carefully planned, and in constant motion, you won't see Pulp Frick Effect videos in the cinema any time soon,
35
it isn't practical for anything more than quick, short gimmicks.
36
Gimmicks like this video.
37
You can take the sunglasses off.
38
One take!
39
One take!
40
Wait, did I go the right way there?
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Vocabulary and speaking notes for this lesson
This B2 speaking lesson is built on the video “This Video Is 2D And 3D Simultaneously: the Pulfrich Effect”. The speaker keeps coming back to these words: eye, image, frame, effect, camera. This video has 40 sentences and 611 words to shadow. The speech runs for 3:29. The speaker talks at a natural 175 words per minute, close to everyday conversation. 85% of the words are among the 3,000 most common in English; the rest is worth studying before you start.
Key vocabulary in this video
The 15 most advanced words in the video, with pronunciation and meaning:
| Word | Pronunciation | Meaning |
|---|---|---|
| sunglasses noun | Tinted glasses worn to protect the eyes from the sun or other bright light, and may also be worn as a fashion accessory. | |
| stereo noun | /ˈstɛəɹ.i.oʊ/ | A system of recording or reproducing sound that uses two or more channels, each playing a portion of the original sound at different locations in order to… |
| gimmick noun | /ˈɡɪm.ɪk/ | A trick or device used to attain some end. |
| cinema noun | /ˈsɪn.ə.mə/ | A movie theatre, a movie house. |
| cutaway noun | /ˈkʌtəweɪ/ | A men's coat with the front cut back away from the waist, as worn on formal occasions. |
| foreground noun | /ˈfɔː(ɹ)ˌɡɹaʊnd/ | The elements of an image which lie closest to the picture plane. |
| opaque adjective | /əʊˈpeɪk/ | Neither reflecting nor emitting light. |
| optometrist noun | /ɑpˈtɑmətɹɪst/ | A person trained and skilled in examining and testing the eyes for defects, in order to prescribe corrective lenses or treatment. |
| polarize verb | /ˈpəʊ.lə.ɹaɪz/ | To cause to have a polarization. |
| simulate verb | /ˈsɪm.jə.lət/ | To model, replicate, duplicate the behavior, appearance or properties of. |
| squint verb | /skwɪnt/ | To look with the eyes partly closed, as in bright sunlight, or as a threatening expression. |
| telethon noun | /ˈtɛl.əˌθɒn/ | A televised fundraising event encouraging viewers to make donations via telephone. |
| simultaneous adjective | /ˌsaɪ̯.məlˈteɪ̯.ni.əs/ | Happening at the same moment. |
| nausea noun | /ˈnɔzi.ə/ | A feeling of illness or discomfort in the digestive system, usually characterized by a strong urge to vomit. |
| induce verb | /ɪnˈduːs/ | To lead by persuasion or influence; incite or prevail upon. |
Phrasal verbs you will hear
| Word | Meaning |
|---|---|
| end up verb | To bring to a conclusion. |
Grammar in this video
The structures the speaker uses most, with the exact words from the video:
| Structure | In the video |
|---|---|
| Passive voice be + past participle — the focus is on what happens, not who does it | are called · been used · be carefully planned |
| Present perfect have/has + past participle — a past action that still matters now | has constantly been · it's been |
Pronunciation to watch
The speaker uses 6 contractions and reduced forms, such as won't, don't, isn't. Say them the short way, as you hear them.
- Long words — get the stress right: optometrist /ɑpˈtɑmətɹɪst/, simultaneous /ˌsaɪ̯.məlˈteɪ̯.ni.əs/, ingredient /ɪnˈɡɹiːdi.ənt/
How to practise with this video
- Listen to the whole video once without speaking and note the words you do not know.
- Start at 0.75× speed, shadow it sentence by sentence, then go back to normal speed once it feels easy.
- Record yourself and compare with the original, paying attention to words like sunglasses, stereo, gimmick.
What is the Shadowing Technique?
Shadowing is a science-backed language learning technique originally developed for professional interpreter training and popularized by polyglot Dr. Alexander Arguelles. The method is simple but powerful: you listen to native English audio and immediately repeat it out loud — like a shadow following the speaker with just a 1–2 second delay. Unlike passive listening or grammar drills, shadowing forces your brain and mouth muscles to simultaneously process and reproduce real speech patterns. Research shows it significantly improves pronunciation accuracy, intonation, rhythm, connected speech, listening comprehension, and speaking fluency — making it one of the most effective methods for IELTS Speaking preparation and real-world English communication.