Candy Chromatography Experiment Ye Jiadong 1A129Science ACE
Candies Ever wondered why candies are different colors? Many candies contain colored dyes. Bags of M&Ms or Skittles contain candies of various colors. The labels tell us the names of the dyes used in the candies. But which dyes are used in which candies? We can answer this by dissolving the dyes out of the candies and separating them using a method called chromatography. In this PowerPoint, I will show you the Candy Chromatography experiment! But firstly, let us state the goals and some introduction first.
Goals The goal of this project is to use paper chromatography to see which dyes are used in the coatings of your favorite colored candies.
Introduction Chromatography is a technique used to separate the various components in a complex mixture or solution. It works because the components of the mixture will differ in how much they "stick" to things: to each other, and to other substances. For example, some of the components of the ink will stick more tightly to the paper fibers. They will spend less time in the water as it moves along the paper fibers, and thus they will not travel very far. Other components of the ink will stick less tightly to the paper fibers. They will spend more time in the water as it moves along the paper fibers, and thus they will travel farther through the paper. Other materials than paper and water can be used for chromatography, but in each chromatography apparatus there is generally a stationary phase and a mobile phase. In paper chromatography, the paper is the stationary phase, and water is the mobile phase. Another example of a chromatography systems is a glass column filled with tiny, inert beads (the stationary phase). The mixture to be separated is added to the column, and is then "washed out" with some type of solution (the mobile phase). In this case, the separation is based on molecular size. Smaller molecules will pass through the spaces between the beads more easily, so they will come out of the column more quickly. Larger molecules will take more time to pass between the beads, so they will come out of the column later. You can separate the smaller molecules from the larger molecules by collecting the liquid that comes off such a column in a series of separate containers.
Experiment Materials: -Candies of Different Colors M&M or Skittles work Well- Filter Paper- Tall Clear Glass or Jar- Water- Salt- Pencil (no pens or markers)- Scissors- Ruler- Toothpicks- Empty 2 liter Bottle and Cap
Process For Candy Chromatography: 1) Cut the filter paper into a 3 x 3 inch squares.2) Take the pencil and draw a line ½ inch from one edge of the paper.3) Plot six dots equally spaced along the line. Leave ¼ inch between the first and last dots and the edge of the paper.4) Under the line label each dot for the colors of candy your going to test. (Y for yellow, G for green, BU for blue, BR for brown).5) Make candy dye solutions. Cut a 10 x 6 piece of aluminum foil and lay it flat.Put six drops of water spaced evenly along the foil. Drop one of each color of candy in the water drops (one color candy per one water drop). Let the candies soak in the water for a minute or two. The color will begin to come off the candy into the water solution. Remove the candy from solution.6) Take a toothpick and dip it into one of the colored candy solutions on the foil. Get the tip of the toothpick wet. Next gently touch the toothpick to the corresponding marked place one the filter paper (blue solution on the dot you marked BU for Blue on the filter paper). Be gentle, we need the dot to be small 1/16 inch or less. Repeat the process using a different toothpick for each color until you have a small dot on each marked part of the filter paper.
Process For Candy Chromatography: 7) Let the colored dots on your filter paper dry.8) Repeat step 6 to get more color dye on each of your filter paper dots. You will need to do steps 6 and 7 a total of three times. Be patient!9) Once you have completed step 8, fold the filter paper in 1/2 so it will stand up on it's own. The dots need to be on the bottom portion.10) Lets make a developing solution next. Measure and put ⅛ teaspoon of salt and 3 cups of water into the empty (and clean) 2 liter bottle. Screw on the lid. Shake until the salt is dissolved in the water making a solution. This is called a 1% salt solution.11) Pour 1/4 inch of the salt solution into a tall glass. The level of the solution needs to be low enough so that when you put the filter paper inside the dots will initially be above the solution level. Hold the filter paper with the dots at the bottom and set it in the glass with the salt solution.12) The salt solution will start to climb up the paper using a process called capillary action.
Process For Candy Chromatography: 13) The solution climbs up the filter paper and moves through the colored dots.The colored dots begin to separate into different color bands. Notice that some candy colors were made from mixing several different dyes. These colors separate into different bands as they move up the filter paper. Dyes separate due to some dyes sticking more to the filter paper and others being more soluble in the solution. As a result the dyes climb will stop at different heights on the filter paper.14) Once the solution gets about ½ inch from the top edge of the filter paper, remove it. Lay the paper out to dry.15) Compare the spots from the different candies, noting similarities and differences. Record your results.Which candies contained mixtures of dyes?Which ones seem to have just one dye?Do similar colors from different candies travel up the paper the same distance?16) Repeat the experiment with a different kind of candy. If you did the M&M's first, then try the skittles.
The real experiment Video If this video does not load, move on to the next slide for the Youtube Version.
The real experiment Video This is the youtube version in case you cannot watch the one in the previous slide. http://www.youtube.com/watch?v=u3msgVXF2mI&feature=player_embedded
Explanation Chromatography is the collective term for a family of laboratory techniques for the separation of mixtures. It involves passing a mixture dissolved in a "mobile phase" through a stationary phase, which separates the substance to be measured from other molecules in the mixture and allows it to be isolated and viewed.
Reflection I had a lot of fun doing the experiment as I got to get a feel of the dyes inside the different candies. However, the results in the end were not very clear, maybe because of the filter paper I used. I used kitchen paper instead of chromatography paper. This experiment was very fun and I enjoyed doing it as it had a lot of significance to our syllabus. I got to hands on with dipping the dyes inside the salt water, looking at how the dyes followed the water up. It gave me an insight as to what dyes were present in the candies. I love doing experiments, especially fiddling with different chemicals as they are every interesting, teaches me more about the relevant subject, such as the dyes present in the candies, and so to say, my goals was achieved. This experiment was a success!