Posted on November 30, 2016 | By cbutlerwoolsery | 5 responses
Today Ashmansworthy class have been learning how chromatography can be used to solve crimes. After our success in separating solids last week, today we learnt how to separate the different coloured components of ink using the process of chromatography. Dots of ink are placed on absorbent filter paper , which is then moistened with water. The water travels across the ink dissolving it, and carries the pigments different distances. The different colours of pigment which make up the coloured ink in a pen dissolve at different rates and produce their own unique pattern. This “fingerprint” can be used to identify exactly which type of pen was used to write, for example, a ransom note or a message from the donut thief. You can then test the different suspects’ pens to find out who the culprit is. Find out more here (clip 20):
The children used chromatography to investigate different types of pens and different types of ink. They also tried using different types of paper such as kitchen roll, paper towels, writing paper and tracing paper to see what happened. They found out that the more absorbent papers were the most effective at separating the ink, and ink which was not water soluble didn’t separate at all.