An inventor – Tim Kehoe – spent 15 years and £2,000,000 developing the world’s first non-staining bubbles – he calls them zubbles!! See http://www.zubbles.com/
The bubbles contain a special dye that fades within 15 minutes of the bubble bursting. This is a clever use of a property of dyes – fading – that is usually thought of as a bad property and which scientists strive hard to eliminate. The special dyes developed for this product fade when exposed to air, light or pressure.
This reminds me somewhat of the breakfast cereal – cocopops – where the brown colorant in the cereal leaks out into the milk turning it a muddy brown colour. Not a nice thing – you might think. However, Kelloggs turned this into a marketing success with the phrase – “So chocolately it even turns the milk brown”. I’ve always thought this was very very clever. Very clever.
But I like it when the milk goes chocolaty?!
I have a question about bubbles…
when we look at a bubble we can see both inner surface and outer surface of it…I’m not sure but I think it’s a totaly transparent object?! But how is it that we only see the colors floating round the bubble, only on the outside surface of the bubble and not on the inner surface???
Thanks for posting this question. The first issue to deal with is why we see bubbles at all if they are totally transparent? Well, the answer to this is that they are not totally transparent – they do not transmit 100% of the light at each wavelength. The main reason for this is the difference in refractive index between the bubble itself and air. This causes about 4% of the light to be reflected back from the external surface. Once light is inside the bubble there is also some internal reflection as the light again passes from a region with one refractive index to a region with another refractive index. So nothing is in truth transparent in air unless it has the same refractive index as air, in which case it probably is air.
Now, why do we see colour? Colour in many objects is caused by the presence of dyes and pigments that absorb light at certain wavelengths to a greater degree than at other wavelengths. However, there are certain colour phenomena such as the rainbox, some butterfly wings, peacock feathers, oil droplets in water etc. that are coloured for quite different reasons. Colour in bubbles is caused by something called interference and the colour in bubbles depends on the thickness of the bubble film. Rather than explain this any further I would direct you to this excellent link that describes colour formation in bubbles – http://www.webexhibits.org/causesofcolor/15E.html.
Of course, the colour in zubbles (the subject of the original post) is caused by dyes (I believe).
ps. Everybody likes the brown milk in cocopops!!