Rainbow in tomato juice
Tools: 100 ml graduated cylinder, two beakers 150 ml, glass rod
Chemicals: solution of bromine water, tomato juice
Procedure: to effectively attempt is needed Bromine water and tomato juice. The attempt to prepare the standard or industrially-produced tomato juice (determining the concentration of the carotenoid lycopene in fruit juice - not thin!) and saturated solution of bromine in water. About 75 ml of tomato juice is poured into a cylinder with a capacity of 100 ml and add such amount of bromine water, which represents about 10-15% of the volume of juice used (ie, about 7.5 to 11.5 ml of bromine water). The mixture in the cylinder slightly stir rod for one minute will be a reaction in which creates a rainbow effect which lasts for several hours.
Originally red juice will gradually from the surface of blue, goes to blue, changing to green and finally to yellow. The resultant effect of generating different colors in this experiment, is dependent not only increasing the amount of bromine water (or its concentration), but also on mixing process.
The red color of tomatoes caused by lycopene pigment that absorbs maximum luminous radiation in the blue-green part of the spectrum. Where double bonds in the chain attacked by bromine, and it requires a string, changes the bond lengths, the wavelength of absorbed radiation changes, and absorption of light shifted to other parts of the spectrum. This will show the resulting change of color in the mixture, to the colloid or may become clear.
Important is the greatest concentration of tomato juice, it is advisable to thicken by evaporation.
Bromine water must be freshly prepared and concentrated.