On Friday 8th February on Google, we noticed there was an eye-catching Google Doodle. When we clicked on it, we realised it was celebrating the life of Friedlieb Ferdinand Runge, the German chemist who discovered caffeine. We learned about his wonderful discoveries and were even more amazed to learn that he pioneered the use of paper chromatography. We took our learning further and experimented with coloured felt tips – we placed a coloured dot on filter paper and watched what happened when water was added. The filter paper absorbed the liquid and the colour molecules got dissolved. Because some of the colour molecules are smaller and lighter than others, they move at different speeds; that’s why the colours look separate!