Dip your finger in the cup of cold tap water to get a drop on the end and let it fall onto one of the coloured dots. You will notice that the paper absorbs the water and it rises up the chromatography paper past the spots of food colouring. When the water reaches the spots, the pigments will dissolve in the water and move up the paper. Jason Chari, Creator of VRChem and the O-Chem (Re)Activity Book / Contributor to QRChem / Student, UCLA Because electromagnetic radiation travels at a constant speed, each wavelength corresponds to a given frequency, which is the number of times per second that a crest passes a given point. Longer waves have lower frequencies, and shorter waves have higher frequencies. Frequency is commonly reported in hertz (Hz), meaning ‘cycles per second’, or ‘waves per second’. The standard unit for frequency is s -1. Evan Darzi, Creator of the Organic Coloring Book series and Contributor to QRChem / Post-Doctoral Researcher, UCLA

This happens because some pigments are more soluble than others. The more soluble the pigment is, the longer it stays dissolved in the water and the further it travels up the paper.Put some water into your beaker just deep enough that the very end of the paper goes into the water. Students are tasked with using the periodic table to find out which group each element is in, which acts as a key for the colours.

High-energy radiation (such as gamma- and x-rays) is composed of very short waves – as short as 10 -16 meter from crest to crest. Longer waves are far less energetic, and thus are less dangerous to living things. Visible light waves are in the range of 400 – 700 nm (nanometers, or 10 -9 m), while radio waves can be several hundred meters in length. where ν(the Greek letter ‘ nu’) is frequency in s -1. Visible red light with a wavelength of 700 nm, for example, has a frequency of 4.29 x 10 14 Hz, and an energy of 40.9 kcal per mole of photons. The full range of electromagnetic radiation wavelengths is referred to as the electromagnetic spectrum. Chromatography is a technique used to separate soluble substances that have been mixed together. It’s normally used to separate coloured mixtures, like food colourings. Francesca Ippoliti, Creator of RSChemistry, VRChem, and the O-Chem (Re)Activity Book / Contributor to QRChem / Student, UCLA

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In a spectroscopy experiment, electromagnetic radiation of a specified range of wavelengths is allowed to pass through a sample containing a compound of interest. The sample molecules absorb energy from some of the wavelengths, and as a result jump from a low energy ‘ground state’ to some higher energy ‘excited state’. Other wavelengths are not absorbed by the sample molecule, so they pass on through. A detector on the other side of the sample records which wavelengths were absorbed, and to what extent they were absorbed. Use this Colour by Symbols: Elements activity with your science classes on Christmas Jumper Day to help them revise groups on the periodic table while creating a colourful Christmas jumper.