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==Dilution and Color== |
==Dilution and Color== |
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The detergent concentration can have a big impact on the color because of its influence on the surface tension which in turn influences the film thickness. Very dilute detergent solutions whose surfactant concentration is in the neighborhood of the CMC (Critical Micelle Concentration) have film thicknesses more heavily influenced by the amount of detergent than solutions where the detergent concentration is higher than the CMC. The dilution ratios where this occurs varies from detergent to detergent. |
The detergent concentration can have a big impact on the color because of its influence on the surface tension which in turn influences the film thickness. Very dilute detergent solutions whose surfactant concentration is in the neighborhood of the CMC (Critical Micelle Concentration) have film thicknesses more heavily influenced by the amount of detergent than solutions where the detergent concentration is higher than the CMC. The dilution ratios where this occurs varies from detergent to detergent. |
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| + | The images below are of similar-sized bubbles created with PEO-based bubble juice whose only difference was the soap dilution. |
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| + | <gallery bordersize="none" spacing="small" orientation="square" columns="2" widths="310"> |
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| + | 20120323 crop 0816 13to1.png|13:1 water:detergent ratio |
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| + | 20120323 crop 20to1 0822A.png|20:1 water:detergent ratio |
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| + | 20120328 crop 25to1 approx rayon 2plybottom.png|25:1 water:detergent ratio |
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| + | 20120328 crop 50to1 rayon 2plybottom3.png|50:1 water:detergent ratio |
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| + | </gallery> |
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| + | ===More Examples=== |
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[[File:20120323_45ishto1_1.png|thumb|left|280px|Rose and green dominate when the water:detergent ratio is high. This bubble was made with Dawn Pro at a dilution of about 45:1 (water:detergent).]][[File:20120328_50to1_rayon_2plybottom1.jpg|right|280px|thumb|Note the pink/green shades typical of very dilute solutions.]] |
[[File:20120323_45ishto1_1.png|thumb|left|280px|Rose and green dominate when the water:detergent ratio is high. This bubble was made with Dawn Pro at a dilution of about 45:1 (water:detergent).]][[File:20120328_50to1_rayon_2plybottom1.jpg|right|280px|thumb|Note the pink/green shades typical of very dilute solutions.]] |
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[[File:C_20121125_3341_HEC_24to1.png|thumb|left|580px|This bubble was created with bubble juice that has a 24:1 Water:Dawn Pro ratio]] |
[[File:C_20121125_3341_HEC_24to1.png|thumb|left|580px|This bubble was created with bubble juice that has a 24:1 Water:Dawn Pro ratio]] |
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[[Category:General]] |
[[Category:General]] |
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[[Category:Science]] |
[[Category:Science]] |
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Revision as of 00:16, 21 January 2013
Created by Bjorn of seifenblasenmann.de and used with his permission
A soap bubble's colors reveal a great deal about the soap film. Because of the way that the colors are created, the colors correspond to the thickness of the film. These colors can provide very useful information. For instance, when creating a large bubble, you can often see large portions of the bubble turn from blue to amber and then start to become transparent. These colors indicate that the film is becoming thin -- and it is probably time to close the bubble.
The colors can also help determine the optimal dilution for a water:detergent mix. When there is a lot of excess soap in the mix, the surface tension will be relatively low which allows the film to be thin. In this dilution range, bubbles will show the range of colors seen on the left portion of the chart. If enough water is added that there is little excess soap (the critical micelle concentration , or CMC, has been approached), bubbles will tend to show the muted (but quite beautiful) pinks and greens seen at the right side of the chart.
There are a few charts which map color to thickness. There is some disagreement (usually small) between the different available charts due to slightly different assumptions about the parameters such as index of refraction, viewing angle, etc.
At left, Bjorn's chart which was generated by theory. Right, a bubble dome section illustrating. Photo by Thomas Poersch.
Bubble dome picture by Thommy
Dilution and Color
The detergent concentration can have a big impact on the color because of its influence on the surface tension which in turn influences the film thickness. Very dilute detergent solutions whose surfactant concentration is in the neighborhood of the CMC (Critical Micelle Concentration) have film thicknesses more heavily influenced by the amount of detergent than solutions where the detergent concentration is higher than the CMC. The dilution ratios where this occurs varies from detergent to detergent.
The images below are of similar-sized bubbles created with PEO-based bubble juice whose only difference was the soap dilution.
More Examples
Rose and green dominate when the water:detergent ratio is high. This bubble was made with Dawn Pro at a dilution of about 45:1 (water:detergent).
Note the pink/green shades typical of very dilute solutions.
This bubble was created with bubble juice that has a 24:1 Water:Dawn Pro ratio
Thank you to Bjorn of Seifenblasenmann.defor the use of his chart.