Can you solve the mystery of the balloons?


Yesterday @jbrownridge brought my attention to this mystery….

These guys were taking photos of air pellets bursting balloons (as you do) and when they looked at some of the photos they noticed something very strange……

“So we were shooting waterballoons with an air gun and taking pictures of it at 60 FPS using the Casio EX-F1. When I looked at the shots afterwards, I WTF’d when I saw the shadow blowing up before the balloon. Does anyone know if there is a reasonable explanation for this, or should I just settle for witchcraft?”

Can you solve the mystery of the balloons?  Try to do it WITHOUT looking at the comments!


95 comments on “Can you solve the mystery of the balloons?

  1. z says:

    Was this the same reason that photos of aircraft propellers taken with iPhone cameras look all funky?

  2. my guess is the camera scans top->bottom doesnt take the image in one shot so you had amazing timing to get the unburst ballon but burts shadow.

  3. Keetje says:

    You can’t see the water on the bright background?

  4. Keetje says:

    I go with comment @2.

  5. fluffy says:

    Rolling shutter.

  6. PreysQuall says:

    due to pressure surrounding of the balloon myb =D

  7. Karen says:

    It had burst, they were small holes?

  8. Fergal Brophy says:

    Nice one,
    My guess is it’s the shadow of a different balloon? The one on the gun-ward side of the one we can see. Let’s see a looser frame which shows more of the scene.

  9. PreysQuall says:

    agreed ! maybe its the balloon is align together so that the shadow can be seen as one. then shoot the balloon at the back and you will see the mystery

    • Berhard says:

      P.S. Alignment won’t wor, as otherwis the visible ballon would be in the shadow of the invisible one… However possibly a back-projection

  10. OutdoorsNerd says:

    I too suspect tech failure in the camera’s sensor scanning top to bottom. Even in a sports shutter setting a bullet is much faster.

    The reflection on the balloon shows that the light soirce is in the right place for the shadow.

  11. Lee says:

    Proof that a camera can never be trusted.

  12. richard says:

    its obvious really, either the pellets were travelling at light speed, or the pellets hit the shadow before the balloon

  13. Mb says:

    Is it alcohol in the balloon? Like if you pour whisky/vodka etc from a jug and you see a shadow of the vapour?

    • Berhard says:

      Remind me of this song: “I shot the shadow, but i did not shoot the baloon… “.. or so …

  14. Peter Kyriacou says:

    Easy. They only shot the shadow.

  15. David Mathew says:

    I don’t have an explanation to offer. But I like this. Thanks!

  16. anaglyph says:

    Digital cameras don’t expose a frame the same way as a film camera – they scan the image (fairly rapidly) or use a combination of mechanical shutter and scan. iPhones don’t have a mechanical shutter at all so they are really good at demonstrating this effect: take an iPhone and make an exposure as you whip the camera quickly across the scene you’re exposing. Instead of a blurry shot (which you’d get with a film camera) you get a distorted ‘stretched’ image. As commenter Z says above, this is noticeable in aircraft propellers and other fast moving things. There’s a really great shot here:

    What I think has happened in the ballon image is that the chip is scanning downward (as Patrick says above) and registers the image of the unburst balloon a tiny fraction of a second before it gets to the shadow. Very lucky timing.

    • Gordon says:

      Actually most film cameras using a rolling shutter as well (a mechanical one), but it goes from side to side.

  17. mightyzim says:

    Its to do with the method the camera scans the light. At 60 fps the scan has done the ballon but not the shadow, in the meantime the ballon has burst and hence the shadow changes instantly, the scan continues and records the burst shadow.

  18. Adrian says:

    You can predict the future by looking at shadows?

  19. Phil says:

    I don’t think its the rolling shutter idea as the water wouldn’t move that fast for that to happen. Only know that to happen due to a flash, but the rest of the screen would be dark.
    I would put bets on something else causing the shadow.

  20. Shek says:

    I suspect that the focus was on the cameras tend to add (pardon the non technical lingo) non jitteriness to the focused areas…it’s usually on the face so if you move around the face is not hazy(less fps on the focused area) be that in this case the the camera is trying to keep the balloon pic stable but the shadow is left as normal.

  21. Phil says:

    or, the bullet skimmed the side away from the camera and the photo is so bright, that the water is over exposed and not visible with the white background.

  22. Kag says:

    Shadow of another balloon out of frame

    Light Source-> Small Balloon1 & Camera -> Balloon2
    Light Source is very close to balloon 1 to prevent enlarging and also perpendicular to balloon 1 so the shadow is block by the balloon itself
    Camera is almost in line with the light Source slightly below the balloon.

    So my guess is a very well angled shot with 2 balloons

    • Edd says:

      Look at the bright spot on the balloon – it’s clearly consistent with the shadow being from the balloon pictured, not a second one.

  23. Phil says:

    Is this shot set up by someone performing a trick though? or is Richard Wiseman seeing if someone can work out why the illusion of the shadow took place from an innocent situation?

  24. Phil says:

    one more guess… Did water burst out the top where its being held, between the balloon and the light?

  25. Shara says:

    Likely has to do with the way cameras work. The CCD is read from top to bottom and because the bursting of a balloon is a fast movement the frame shows the instance where the camera had read the moment right before the bursting of the balloon but by the time it got to the bottom of the balloon, the balloon had already exploded and so it captured the shadow cast by the burst balloon.

  26. cozdas says:

    definitely “rolling shutter”. *nod*

  27. Paul Durrant says:

    I’d say patrick neville has it right. It’s what I thought before looking at the comments. The camera doesn’t take a frame in one instant but reads it out of the CCD top to bottom.

  28. Andy C says:

    I would agree that it’s due to the chip scanning downwards. The effect has been around for many many years as the same effect could be observed with focal plane shutters on traditional cameras.

    I first came across it in an article by the golf Journalist Peter Dobereiner. He set up four Cameras set to fire in sync, Two in Portrait mode, but one with the shutter travelling upwards and one downwards, one horizontal and one with an Iris shutter. Then he took a photo at the point of impact of a pro hitting a ball . The Horizontal and Iris shutters, both showed a blurring of the club shaft due to the movement during the exposure. But the camera with the shutter travelling upwards showed a marked backwards bend in the shaft, and the one travelling downwards showed a forward bend. He explained that these illusions were till then (Late 60’s?) used to illustrate either the whippiness of “Modern” Clubs as if the club had sprung forward and imparted more force into the ball, or the famed, “Late Hit” timing of the top pros. In actual fact it was purely down to whether the cameraman turned the camera to the right or left to get into portrait position.
    It’s explained (though not as well as Peter did it IMHO) here:-

  29. Javier Aranda says:

    You took the picture with the camera shutter open. The balloon before the one in the picture burst. You put another balloon and you got two shadows. The one bursting and the new balloon one.

  30. Peter McKay says:

    Straightforward really!!

    The pellet enters the far side of the balloon, so the front appears intact.
    The water IS coming out but the sun is shining from the front and above The light reflects off the water, making it harder to see against the pale background, but the shadow proves it is there. If it was filled with a coloured liquid there would be a mystery. It would be more surprising if the balloon had burst and the water had no shadow.

    You need a lot more information to be certain of anything.

    • Gert says:

      I almost thought I had to type it out myself, but you perfectly worded my thoughts.

      I’d love to see the math on the sensor scan suggestions though.

  31. trollololol says:

    The retarded people who still comment with (seemingly serious) incorrect explanations when #2 got it right are retarded.

    • Neil says:

      Oh, I’m sorry, contestant – your score was too low to register on the trollmeter for this forum, so we can’t include you in the all-time list. Keep trying, though – everyone can improve if they try really hard.

      Tip: try to vary the insults within your post – using ‘retarded’ twice, for instance, betrays a woeful lack of imagination, even when it does echo the ‘serious cat is serious’ meme…

  32. Berhard says:

    I would use a second ballon and a light arrangement sutiable to hide the shadow of the visilbe ballone and to project the shadow of a second non-visible ballon to the white wall..

  33. markcromp says:

    Maybe you missed and hit it on the rebound from the backboard and then got that shot because the shot had hit the other side of the baloon but not reached the camera side yet.

  34. PreysQuall says:

    nice infos !

  35. Noel says:


    Can you enlighten all of us with the correct answer tomorrow.

    My head hurts now reading all the comments.


  36. James says:

    my guess is your not seeing the water on the background but heat or something similar

  37. Caspar says:


  38. DM says:

    The background is fake, it is painted/printed on the white board.

  39. Mark_D says:

    Sometimes, programs in the matrix do not do what they’re supposed to do. Obviously, the shadow program is malfunctioning and must return to The Source.

    The Oracle explained this all quite succinctly in part II, and I don’t understand why you’re all avoiding the obvious. Too much blue pill?

    • Greg23 says:

      You watched it on T.V. last night too? (Matrix)

    • Mark_D says:

      Haven’t seen it in a while, but I’m one of those very rare people who liked all three installments. Even wackier, I thought the best part of the series was the Architect’s speech at the end of the second movie… beats all the special-effect kung-fu.

  40. Stephen says:

    The light and the (bursting) balloon are behind the sheet

  41. Tom says:

    Either the solution in comment #2 or fine droplets of water that the light from the sun is refracted through, deflecting the light and leaving a shadow behind the fine droplets.

  42. Ken T. says:

    Something to do with interpolation between the video fields/frames.

    And witchcraft.

  43. jtradke says:

    It has to do with wibbly-wobbly, timey-wimey… stuff. You wouldn’t understand.

  44. Paul Pearson says:

    I am pondering only the faintest, hypothetical reason for the difference. It is nothing I can easily test, but desire to see if I am right (doubt it).

  45. Rob McD says:

    Meh. It’s obvious. This was Lucky Luke’s shadow getting its own back.

  46. Santiago says:

    Hmm, too bad this is a bit late but: yes, Rolling Shutter is undoubtedly the explanation. A bit of googling let me know that this particular model of camera has a CMOS sensor. CMOS sensors almost always feature a Rolling Shutter (unlike CCD sensors, which do not) so I would say this is case closed.

  47. Daniel Robertson says:

    *I haven’t looked at the comments*

    I don’t know much about the software/mechanics of the camera in question (or any camera, for that matter!), but my guess is that the exposure ‘scans’ downwards, i.e. the image is ‘processed’ line-by-line from the top down, and the time this takes is enough for a frame taken at just the right moment to capture this image.

    Maybe if you turned the camera upside down, and were lucky enough, you could get the balloon popping before the shadow?

    *Now to see if I’m even close…*

  48. Smart_Cookie says:

    I’m thinking it might just be a rush of air being expelled from the balloon, before it bursts.

    In the shadow image, the balloon hasn’t burst yet – it’s only gas/air escaping.

  49. redcat says:

    Eh, don’t know… the water is actually escaping but you can’t tell it from the background wall color?

  50. SimonP says:

    Hot air rises, so the air in front of the balloon is less dense than the air in front of the shadow. This means the light travels faster from the balloon than from the shadow. Therefore shadow we see is slightly older than the balloon. With the bullet travelling faster than light speed (as Richard commented above) the balloon actually bursts after the photograph has been taken. It’s all very simple really.

    • SimonP says:

      PS I flipped the image vertically in Photoshop and the reverse effect is now visible: The balloon has burst, but the shadow has not.

  51. […] Can you solve the mystery of the balloons? Yesterday @jbrownridge brought my attention to this mystery…. […]

  52. Robert Pound says:

    i 99% sure i have it when can se give the answer?

  53. Robert Pound says:

    dont think its the camera

  54. Dave Rickey says:

    I’m going with the “rolling shutter” theory, especially since the shadows of the splash seem “smeared” downwards, exactly as if some of the water drops were keeping up with the advancing line of the scan. In game development you could see a similar effect called “tearing” where the video render wasn’t locked to complete a frame before changing the scene (doesn’t happen with newer cards unless both the programmer and end-user set things up to allow it).

    I remember seeing something almost identical to this when our particle generator wasn’t frame-locked but our main renderer was, if you took a screenshot at exactly the right time you saw the bottom of an explosion emanating from an object that appeared intact.


  55. PreysQuall says:

    agreed with the Rolling Shutter Theory =D
    seem to have the answer LOL

  56. Andrew scuffam says:

    My guess would be that the camera’s sensor doesn’t capture the image all at once. It very quickly scans the image from the top of the sensor to the bottom maybe it takes 1000 ths of a second, so when it got to the bottom of the balloon it hadn’t burst yet, but when it got to the shadow it had

    If the shadow was lower it may have captured the balloon whole, but the shadow may have shown the balloon burst more than the picture provided

  57. Steve Jones says:

    It’s a artefact of the way the image is read off the sensor which is clearly bottom-to-top. “Rolling Shutter” artefacts are well known in videography.

  58. Daniel Boone says:

    This is the “redshift” phenomenon familiar to astronomers. Only it works in reverse, because the balloon is green, which is the opposite of red, which is why the *shadow* shows up first, not the balloon…

  59. SteveG says:

    I think it’s 2 balloons.

    The shadow of the water looks like is already beginning to fall down, not the symmetrical burst you’d expect if it was caught at the exact instant of contact. A split second later the water is beginning to fall and the hidden balloon is already shrinking so it is well behind the first balloon.

    That being said, it looks like there’s a dark line below the first balloon which could almost be the bottom of the hidden one.

  60. Jon d says:

    I’m almost convinced by the vertical scan explanation. But I’d expect the shadow of the exploding water to be horizontally narrower at the top than the bottom which it isn’t.
    Also the baloon shadow doesn’t look quite right to me, like it’s being cast from a different angle to that implied by the reflected light on the balloon.
    Dunno if you can do a double exposure with that sort of camera, I’m thinking perhaps a double exposure of
    1 a flash photo of the balloon against a dark background
    2 the balloon infront of a back projection of the shadow from behind the white screen.

  61. Ricardo says:

    I don’t think it’s as technical as suggested. It’s a bright sunny day. The photograph was made outdoors as grass is evident at the bottom of the wall. The brightness of the sun implies that it is almost overhead and yes that would produce the reflections seen on the balloon. The balloons shadow would fall on the ground. I now angle the wall backwards so that I can cast a balloon like shadow on the wall with a cut opaque elliptical shape held outside of the frame above the wall. Note the shadow does not match the balloon shape. Close but not perfect. Also there is no hint of color in the shadow that might occur from a green translucent balloon. Take first shot. Then pull up some grass and add it to the out of frame false form so that it looks like water. Take the second shot. Note the water shadow is opaque, not transparent, and occupies a clearly defined area. Looks like grass. Also, the skin of the balloon does not appear to be ruptured.

  62. Paritus says:

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  63. BigSoph says:

    I am guessing it is the ghost of the balloon!

  64. kevin says:

    comment number 2.,good explanation.,

  65. Elliptical…

    […]Can you solve the mystery of the balloons? « Richard Wiseman[…]…

  66. oyun says:

    Was this working for me too, thanks

  67. Anonymous says:

    Maybe it’s like in Peter Pan.

  68. Lynsey says:

    My dream retirement is living on a 45ft center cockpit Hunter sailboat with my man and dog sailing the inter coastal waterways, the Caribbean, and any port I choose.

  69. Anonymous says:

    This is easy it is rolling shutter effect

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