By carefully cutting and re-joining the clear plastic sides of an ordinary CD case into four equal trapezoids to form a pyramidal shape you can create holograms with your I-pad or smart-phone. [link]

I whipped up one of these for my daughter and I wanted to see if the effect would work even when the pyramid was submerged. It does!

By placing the pyramid base-down to the underside of the tank lid and lowering the surrounding lighting you can have glowing 3D jellyfish or butterflies or fireworks for the enjoyment of your little fish friends.
-- 2 fries shy of a happy meal, Nov 06 2015

https://www.youtube...watch?v=JqyK7CNZx2g [2 fries shy of a happy meal, Nov 06 2015]

Apparently a laser is required... https://en.wikipedia.org/wiki/Holography
[normzone, Nov 06 2015]

No laser required http://home.earthli...nblack/hologram.htm
[pocmloc, Nov 06 2015]

This is Alpha, my beta... in his delta. https://www.youtube...7g&feature=youtu.be
Skip to 2:00 to see how clear it is even in full light. [2 fries shy of a happy meal, Nov 07 2015]

Holoquarium 2 https://youtu.be/rRZ1Yt2JKME
[2 fries shy of a happy meal, Mar 05 2018]

cool! +
-- xandram, Nov 06 2015


That is completely awesome! [+]

I'm now wondering how to make the pyramid (a) big enough to work with a large screen and (b) more invisible.
-- MaxwellBuchanan, Nov 06 2015


Would it work if the fish-tank itself were pyramidal? The you wouldn't be able to see how the hologram was cast.

I've got some plexi-glass left over from building the S.S. Sea Threw and think I'm going to try it out.
Is there any strange optical property to the plastic used in CD case manufacture that would prevent plexi-glass from working?
-- 2 fries shy of a happy meal, Nov 06 2015


Yes [bigs], I wasted 1/2 an hour of my life trying to calculate ray paths from each eye to work out how the multiple projected images combined to give 3D.
-- pocmloc, Nov 06 2015


Well, the image on the iPad is flat, so it would be pretty surprising if the reflected image wasn't...
-- MaxwellBuchanan, Nov 06 2015


So... it's not a hologram? It sure makes you want to stick your fingers in there to try and touch it. Well, the poor fish just gets to see four images beneath it 'cause todays contract was a no-go and I'm just waiting for the silicone to dry on my new Tranlucentscreenaquarium.

muhahahahaha
-- 2 fries shy of a happy meal, Nov 06 2015


HA!
That worked WAY better than I thought it would.
I'm just all giddy like a little schoolgirl.

halfbakery, I'd like you all to meet Alpha. [link]
-- 2 fries shy of a happy meal, Nov 07 2015


This is four pepper's ghosts leaning against each other. Please don't call it a hologram.
-- tatterdemalion, Nov 07 2015


Well, that didn't work. Let's try another [link].

Sorry [tatteredmedalion] you are absolutely right and the name will be changed to reflect this.
: ]
-- 2 fries shy of a happy meal, Nov 07 2015


Okay, that's neat. Can the fish see the hollowgram ?
-- FlyingToaster, Nov 07 2015


The fish sees the image beneath itself.

I didn't think it would be anywhere even near that visible in full light.
-- 2 fries shy of a happy meal, Nov 07 2015


Thought you guys might like to see the second prototype.
[link] #5

Unfortunately Alpha is no longer with us but has gone on to a better place.
No he's not dead, I just had to sell him and his store-bought tank in a garage sale... but his legacy lives on.

How do you think I got him in there?
-- 2 fries shy of a happy meal, Mar 05 2018



random, halfbakery