Dissolving colour - Resene

Notes

Dissolving colourIf you have ever left a note in your pocket when yourclothes have been washed you will know that colourscan dissolve making it impossible to read the note. Eachcolour pigment is made up using a mixture of colours.The human eye can’t see the individual colours unless thecolour is split. You can split colour using chromatography,which dissolves colours to see what they contain.Everywhere colour - Dissolving colour 1Notes

Now try it yourself...1Cut a narrow piece of paper towel and draw a line usinga black felt pen about 4 centimetres from the bottom.2Fill a glass half fullwith water.3Place the paper towel in it so the line youhave drawn is about 1 centimetre higherthan the water in the glass. Make sureyour line is above the water. Hold thepaper steady.4The water will be absorbed into the papertowel and through a capillary action will startclimbing up the paper. Once it reaches yourblack line the colour will start to dissolve.The dissolving colours will travel upwards atdifferent rates as the water moves upwards.2 Everywhere colour - Dissolving colourNotes

Hold the paper steady andwatch as the water travels uptoward the black line. Whathappens to the black line?Everywhere colour - Dissolving colour 3Notes

Once the colour moving upwards has slowed, take the paper towel out of the water and leave to dry. Ifyou look at your paper you can see the original line and see the colours that have dissolved.The inks in felt pens are made up of more than one colour. The water spreading separates the colours,which is why you can see many colours rather than just the one colour you started with. The colours thatdissolve the best will travel the highest.Try the experiment again this time using other felt tip pens4 Everywhere colour - Dissolving colourNotes

NotesEverywhere colour - Dissolving colour 5

If you were given a note written in felt pen with no name on it, you coulduse chromatography to learn which pen was used to write it. You couldtest the note by placing the bottom in the water and watching thecolour dissolve. You could then test various pensuntil you found one where the colour dissolvesthe same way as the note.6 Everywhere colour - Dissolving colourNotes

Scientists use chromatography to test fordiseases. They compare healthy samplesto samples taken from patients. If thepattern of the patient’s sample is differentto the pattern of the healthy sample thismay suggest the patient has a disease thatneeds curing.Everywhere colour - Dissolving colour 7Notes

Learn more about colour with the Resene Everywherecolour series. Modules include:Changing colourColour wheelsColour and natureColour in artColour of lightDecorating colourDissolving colourDotted colourEverywhere colourEyes and rainbowsFiltering colourIllusion and tricks with colourMaking colour - DyeMixing colourReflecting colourSafety colourSeeing colour - AnimalsSeeing colour - HumansIn Australia:PO Box 785, Ashmore City, Queensland 4214Call 1800 738 383, visit www.resene.com.auor email us at advice@resene.com.auColours printed as close as printing process allows.In New Zealand:PO Box 38242, Wellington Mail Centre, Lower Hutt 5045Call 0800 RESENE (737 363), visit www.resene.co.nzor email us at advice@resene.co.nzNotes