Sweet Chromatography

Introduction
Public summary: 

Using just water and bits of paper, split up the colours in pens and food colourings to see how they're made up of a mixture of differently coloured dyes.

Using chromatography to investigate the colour of food.
Useful information
Kit List: 

Cotton wool buds
Water
Sweets - M&Ms, Smarties, other sweets with suitable food colouring, water soluble felt-tip pens
Cotton wool buds
Filter Paper
Plastic containers

Packing Away: 

Lives in Misc Box

Explanation
Explanation: 

In this experiment the children will investigate the food colourings found in sweets, and dyes from felt-tip pens using chromatography. This will show that colours like brown actually consist of other colours, which we can separate using water.

Possible Activities:
Separating the food colouring components from sweets and dyes in felt-tip pens.

Tips for demonstrating:
Prepare some in advance, so if it takes a long time, or you want to show multiple dyes at once, you have some examples.
Label the dye samples so that you can remember which is which!
Test similar dyes from different sweets, e.g. brown Smarties and brown M&Ms.
The best dyes are brown colours as they tend to have the most components.

*** BASIC PROCEDURE AND EXPLANATION ***

Moisten the end of one of the cotton wool buds with water.
Use this to get some of the food colouring off the sweets.
Use water to moisten a piece of filter paper, or better still fill a plastic cup with water and use a paperclip to suspend the filter paper so it only has a small amount of paper under the water level.
Transfer this dye to the piece of filter paper near the water.
Leave for a while until the dyes separate.
Talk about the solubility of the different dyes and how this affects how far the water 'carries' the dye up the filter paper.

[Slightly more advanced explanation- Chromatography in general involves a stationary phase (in this case filter paper) and a mobile phase (in this case water). Different compounds have different levels of affinity for the stationary phase, and so are carried over it by the mobile phase at different speeds, resulting in their separation.]

*** OTHER THINGS TO TALK ABOUT ***

Different ways of separating components from a mixture.
Uses of chromatography.

*** SCIENCE BACKGROUND FOR DEMONSTRATORS ***

Simple chromatography

Risk Assessment
Date risk assesment last checked: 
Wed, 17/01/2018
Risk assesment checked by: 
grh37
Date risk assesment double checked: 
Sun, 04/02/2018
Risk assesment double-checked by: 
Giedre
Risk Assessment: 

Getting food colouring off Smarties and other sweets, and then using filter paper to do chromatography with the dyes.

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Hazard Risk Likelihood Severity Overall Mitigation Likelihood Severity Overall
Sweets Children will want to eat the sweets which will not be clean. Likelihood score Severity score Overall Explain to the children that the sweets are not clean, and that they should never eat any food used in an experiment/in the lab.
If ingested, warn parents to seek medical advice if illness develops in their child after the event.
Likelihood again Severity again New overall (hopefully better than the first)
Sweets Choking hazard with very small children if they swallow the sweets. Likelihood score Severity score Overall Watch small children, and don't let them play with the sweets.
In the event of an accident, call first aider, who may perform the Heimlich if confident and trained to do so.
Likelihood again Severity again New overall (hopefully better than the first)
Water Trip hazard from spilt water, particularly on laboratory floors. Likelihood score Severity score Overall Place plastic cup in a place where it won't be knocked over easily. Mop up any spilt water immediately.
Call a first aider if an accident occurs.
Likelihood again Severity again New overall (hopefully better than the first)
0
0
Images
Publicity photo: 
Experiment photos: