The activity shows children how chromatography can be used as a separation technique – in this case as a way of separating mixtures of dyes and colours. Practical considerations Drawing conclusions and raising further questions that could be investigated, based on their data and observations. Draw a horizontal line with a pencil and ruler about 1 cm above the bottom of a piece of chromatography paper. Just like ocean waves, electromagnetic waves travel in a defined direction. While the speed of ocean waves can vary, however, the speed of electromagnetic waves – commonly referred to as the speed of light – is essentially a constant, approximately 300 million meters per second. This is true whether we are talking about gamma radiation or visible light. Obviously, there is a big difference between these two types of waves – we are surrounded by the latter for more than half of our time on earth, whereas we hopefully never become exposed to the former to any significant degree. The different properties of the various types of electromagnetic radiation are due to differences in their wavelengths, and the corresponding differences in their energies: shorter wavelengths correspond to higher energy.

Jason Chari, Creator of VRChem and the O-Chem (Re)Activity Book / Contributor to QRChem / Student, UCLA 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.

What topics will my child learn about in science?

Place a small spot of the coloured mixture you are investigating onto the pencil line and allow it to dry. 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. 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. 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.

You might like to add spots of some pure coloured pigments alongside it, so that you can see if they are present in the mixture.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. Francesca Ippoliti, Creator of RSChemistry, VRChem, and the O-Chem (Re)Activity Book / Contributor to QRChem / Student, UCLA Stand the tube on a white surface and shine the torch through the opening and look down the top of the tube. This activity can form the basis for a group discussion where children look at how dyes and colours in pens and sweets are made. Alternatively, the resource can be used to generate questions and discussions around the topics of light, or dissolving and reversible changes.

The notion that electromagnetic radiation contains a quantifiable amount of energy can perhaps be better understood if we talk about light as a stream of particles, called photons, rather than as a wave. (Recall the concept known as ‘wave-particle duality’: at the quantum level, wave behavior and particle behavior become indistinguishable, and very small particles have an observable ‘wavelength’). If we describe light as a stream of photons, the energy of a particular wavelength can be expressed as: The colour of inks and other coloured objects can be made up of a mixture of multiple colours and dyes.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. Carefully lower your paper into the water, letting the glass rod balance on the rim of the beaker. Make sure the pencil line is above the surface of the water. Put some water into your beaker just deep enough that the very end of the paper goes into the water.

Choose a stencil pattern and colour-in the dots using a selection of colours, or design your own using a series of dots. This makes revising groups and elements a fun an engaging task, as well as helping tie it into Christmas Jumper Day with a festive twist. We are going to use chromatography to separate these different food colourings into the coloured pigments they are made from.Evan Darzi, Creator of the Organic Coloring Book series and Contributor to QRChem / Post-Doctoral Researcher, UCLA Here is the key to molecular spectroscopy: a given molecule will specifically absorb only those wavelengths which have energies that correspond to the energy difference of the transition that is occurring. Thus, if the transition involves the molecule jumping from ground state A to excited state B, with an energy difference of ΔE, the molecule will specifically absorb radiation with wavelength that corresponds to ΔE, while allowing other wavelengths to pass through unabsorbed. Or for some more science word fun, you could try this Science Word Unscramble activity. Can your child work out which word has been scrambled up? This task is great for developing your kid’s problem-solving skills! What is mindfulness? Follow these steps to try out standard chromatography. You will need: a pencil, a ruler, a piece of paper, a coloured mixture such as a food dye.