Coloured Chemistry with Smartphones: Test the Beer-Lambert Law with blue copper solution

When copper gets dissolved in an aqueous solution of nitric acid, the solution is turning blue. The more copper is added the more intensive the colour gets. But how can you figure out how much copper was used exactly by only looking at the colour?

The teaching unit ‘How deep is Your Blue? – Coloured Chemistry with Smartphones’ shows how students can use the smartphone to determine the precise amount of copper that turned the solution blue. Therefore the students collect comparative values of different copper-solutions with special apps to produce a diagram to estimate the amount of copper. Based on the Lambert-Beer Law that explains that the absorption of light, which gives the colour, is proportional to the concentration of the dissolved colorant the students receive their results.

For this teaching unit the students should be at an age between 13 and 18 years, for certain knowledge in chemistry and maths are presumed.

Authors: Daniel Bengtsson (S), Lilla Jónás (HU), Miroslaw Los (PL), Marc Montangero (CH) und Márta Gajdosné Szabó (HU) | Hg. Science on Stage Deutschland e.V. | Lizenz: Creative Commons