Blog Archives

Candy Chromatography

6/21/2015

Author: Maddie Van Beek

http://8ehebetang.weebly.com/uploads/1/0/8/2/10829980/487098.png

Watch the video below. Where are the colors in the black jelly bean coming from? Make a prediction!

Have you ever wondered how candy is made in so many different colors? Candy companies use a number of different dyes to create the colors you see in M&Ms or Skittles, for example. If you look on the nutrition label, you might see colors such as Red 40 or Yellow 6. These dyes are combined to make all the colors you see on your favorite candies. By using a process called chromatography, you can actually separate the dyes in your candy to find out which colors were used, and that’s what we are going to do today!

Candy dye isn’t the only thing you can separate using chromatography. If you did our fall leaves chromatography, you are already an expert! If you missed it before, check out our previous chromatography experiment. This is a fun activity to keep in mind for the end of the summer: http://discoveryexpress.weebly.com/homeblog/is-a-black-marker-really-just-black-is-a-green-leaf-really-only-green-these-are-the-questions-well-answer-today-using-chromatography

Before we try our activity, let’s learn about what chromatography means.

Chromatography is a process in which a material is separated into its individual components. The word chromatography comes from two Greek words:

Chroma, “color,” and graphein, “to write.”

In the picture below, you can see that the original colors at the bottom of the paper have been separated into several different colors.

http://www.thamesandkosmos.com/products/images/ch/c1000_8.jpg

Here’s another example of markers that have been separated into different colors. As you can see, black ink isn’t just black! You are going to use this same process to separate the dyes in candy.

https://www.manylabs.org/file/lessonMedia/80/markerResults.jpg

To learn more about the process of chromatography, read the background section of our last post on chromatography: http://discoveryexpress.weebly.com/homeblog/is-a-black-marker-really-just-black-is-a-green-leaf-really-only-green-these-are-the-questions-well-answer-today-using-chromatography

YOU WILL NEED:

M&Ms or Skittles candies (1 of each color)
Coffee filter paper
A tall glass
Water
Table salt
Pencil
Scissors
Ruler
6 toothpicks
Aluminum foil
2 liter bottle with cap

Here’s what to do!

Use the ruler to measure a 3 inch by 3 inch square of coffee filter paper and use the scissors to cut it out.
Measure 1/2 inch up from the bottom edge of the paper and draw a horizontal line across the whole piece of paper.
Starting from 1/4 inch in, make six dots equally spaced along the line. You should leave about 1/4 inch between the last dot and the edge of the paper.
Below the horizontal line, label each dot with a color of candy that you have.
Now you need to dissolve the dye off of the candy. Cut out an 8 inch by 4 inch piece of aluminum foil and lay it on a flat surface. Place one color of each candy on the foil. Make sure there is plenty of space between each piece.
Carefully drop a bit of water on each piece of candy and wait for the color to dissolve into the water.
Once the color is dissolved, carefully remove the candies and throw them away.
Now you are going to transfer the dye onto the filter paper. Dip a toothpick into the red candy color and transfer it to the dot labeled red on the filter paper.
Use a second toothpick to transfer the next color to its corresponding dot. Repeat until you have transferred each color to its dot on the filter paper.
Wait until the dots have dried, and then repeat this process two more times to make sure you have transferred enough color for the experiment to work.
Once the dots on the filter paper have dried, fold the paper in half so the fold is on the top and the dots are on the bottom.
Next, you will make a developing solution out of water and salt. Add 1/8 teaspoon of salt and three cups of water to a clean 2 liter bottle. Screw the cap on and shake the bottle until the salt is completely dissolved.
Pour 1/4 inch of the salt solution into a clear glass.
Place the filter paper over the edge of the glass so that the very bottom of the paper touches the water but the dots stay above the water.
Once you place the filter paper in the glass, you should see the water slowly climb up the filter paper. As the solution climbs, the color dots start to separate and move up the paper.
When the salt solution has climbed to the top of the filter paper, remove the paper from the glass and lay it on a flat surface to dry.
Once the filter paper has dried, analyze the results. Which dyes separated into more than one color? Did some stay the same? Which ones traveled the furthest?

Follow-up Questions: You may need to check your background information!

Why did some colors separate while others did not?

Did some colors travel farther than others? Why do you think this is?

In this experiment, what was the mobile phase and what was the stationary phase?

Extension:

Experiment with different types of candy to see if they use the same dyes. For example, you could compare Skittles to M&Ms. Why would you do that? Some candies might contain different kinds of dye. A red M&M might have a different dye combination than a red Skittle. Try it out and record your observations.

References:

0 Comments

Floating Egg

6/14/2015

0 Comments

Author: Maddie Van Beek

Have you ever heard that muscle weighs more than fat? The truth is, a pound of muscle weighs the same as a pound of fat! It’s just that muscle is denser than fat. Check out the photo below:

http://cdn2-b.examiner.com/sites/default/files/styles/image_content_width/hash/4d/e6/4de678acd329b0766b9f2b067d49fec6.jpg?itok=x7A5pn0j

As you can see, one pound of muscle simply takes up less space than one pound of fat. This is because the material in muscle is more dense than the material in fat.

How much do you know about density? If you’ve been following us for a while, you may have tried our liquid stacking tower experiment that demonstrates the densities of different liquids. Check that out here (http://discoveryexpress.weebly.com/homeblog/rainbow-in-a-jar-learning-about-liquid-density)! Today, we are going to create an easy demonstration involving liquid density just by using an egg and salt water.

What IS density?

http://astro.unl.edu/classaction/outlines/intro/density.jpg

Even though two different items might take up the same amount of space, their densities may be different. Take a look at the photo below. All of the cubes are the same size, yet some of them weigh more than others. Why is that? Because their densities vary. For example, wood is less dense than steel.

http://www.flinnsci.com/store/catalogPhotos/AP6058cat.jpg

http://inspirationlaboratories.com/wp-content/uploads/2012/11/density-comparison.jpg

As you can see, the object on the left side has greater density than the object on the right side. Although both cubes are the same size, the matter in the left cube is packed more tightly, and thus is more dense than the cube on the right.

Here is yet another example of the varying densities of different materials.

http://www.mathswrap.co.uk/wp-content/uploads/2013/03/Density-cubes.jpg

Make sense?

Now that you understand the basics of density, here is a video that explains how to find density:

Let’s try our density demonstration!

YOU WILL NEED:

Water
Salt
An egg
A glass
Teaspoon

Here’s what to do!

First, fill a glass with one cup of plain water.
Carefully drop the egg into the glass of tap water. What happens? Make a sketch of the egg in your observation journal and record any other observations.
You should have seen the egg sink to the bottom of the glass of tap water. What do you think will happen if you drop an egg in a glass of salt water? Let’s find out!
Remove the egg from the glass, and then use a teaspoon to stir salt into your glass of water. Make sure the salt dissolves completely before you add more. Count how many teaspoons of salt it takes before no more salt will dissolve. When you reach the point where salt will no longer dissolve, your water is saturated. You cannot dissolve an unlimited amount of salt (or any solute). Liquids (a solvent) reach a certain point where they will no longer dissolve any more solute (in this case, salt).
Now that you have your salt water solution, carefully pour half a cup of tap water on top of the salt water. Make sure you do this so that you disturb the salt water as little as possible. What do you think is more dense, the salt water or the tap water? Why?
Carefully drop the egg into the glass of water. What do you see? How was this different than the first time you dropped the egg into the tap water?
You should have seen the egg sink past the tap water in the top half of the glass until it hit the salt water. It “magically” floats in the middle of the glass. Why does it do this? As you know, the salt water is more dense than the tap water, so the egg sinks right past the tap water but floats on the surface of the salt water.
Extension: How else can you determine which liquids are more dense? Use a balance to compare different liquids. Make sure you use two identical cups with equal amounts of liquids when you are making comparisons.
Look at the example below: You can see that water weighs more than an equal amount of rubbing alcohol. This means that the rubbing alcohol is less dense than water.

http://www.middleschoolchemistry.com/img/content/lessons/3.5/alcohol_vs_water.jpg

10. Find other household liquids that you can compare! Make sure to record your observations in your observation journal.

Since you have eggs already, check out these other “eggcellent” activities!

Acid Base Reactions: http://discoveryexpress.weebly.com/homeblog/experimenting-with-eggs-acid-base-reactions-and-osmosis

Nature Abhors a Vacuum: http://discoveryexpress.weebly.com/homeblog/nature-abhors-a-vacuum-how-to-put-an-egg-in-a-bottle

Sedimentation and Crystallization: http://discoveryexpress.weebly.com/homeblog/sedimentation-and-crystallization-how-to-make-egg-geodes

References:

0 Comments

How does color affect heat absorption?

6/7/2015

27 Comments

Author: Maddie Van Beek

Did you know that different colors absorb different amounts of heat? Colors are NOT all equally heat absorbent. Think of walking out on the black tar in the summer time without shoes. Yowch! Walking on the sidewalk pavement or in the dirt is much easier on your bare toes! Why is that?

Let’s find out!

Why would anyone care what color their roof was? Well, take a look at the graph below.

http://www.ips-innovations.com/bilder/exterior_coatings_2008/roof_surface_temperature.jpg

What do you notice about the different materials? Do the materials affect how hot the roof got? Why do you think this is?

When light interacts with an object, that light can be absorbed, reflected, or transmitted. Black objects absorb all wavelengths of light, while white objects reflect all visible wavelengths. They are complete opposites. Other colors absorb some wavelengths and reflect others, which is what makes them appear different to the human eye. Color is a result of the wavelength of light reflected by that object. For example, an object that absorbs selectively yellow light will not look yellow; it would be a combination of every other color besides yellow. The color you observe is a complement to the color the object absorbs. Take a look at the color wheel below.

http://2012books.lardbucket.org/books/principles-of-general-chemistry-v1.0/section_10/d4e464930933cb2a2ea7bfdd5cd23416.jpg

If red is being absorbed, then what color will you observe?

If you observe violet, what color light is being absorbed?

When an object absorbs light, it usually converted from light energy to heat energy. This is what we are focusing on in our activity today!

Activity: How does color affect heat absorption?

YOU WILL NEED:

2 glasses
Water
Black construction paper
White paper
Tape or rubber bands
Thermometer
A sunny day

Here’s what to do!

1. Find two identical glasses.

2. Cut black construction paper to the same height as one of the glasses.

3. Wrap the black construction paper around the glass so it covers the entire outside surface, as well as the top.

4. Tape the paper in place or put a rubber band around the glass to hold the paper in place.

5. Repeat steps 2-4 with the second glass with the white paper.

6. Fill both glasses with water. Make sure they have the same amount of water in them, and make sure you use the same temperature of water in both glasses.

7. Take the temperature of the water in each glass and write down the starting temperature.

8. Place both glasses outside in the sun.

9. Use the thermometer to take each glass’s temperature every 15 minutes for two hours. Carefully make a small hole in the paper at the edge of the glass to insert your thermometer.

10. Record your observations as you go. What did you notice?

11. When the two hours are up, create a line graph to track the temperature change in each glass. Temperature should be your Y-axis and time should be your X-axis. Did one glass heat up faster than the other? Did they both reach the same temperature at the end?

You should have found that the glass wrapped in black paper ended up with hotter water than the glass with white paper. This is because black absorbs more light (and thus, heat) than white. Clearly, black and white are on opposite ends of the color spectrum. Try using different colors to see how much of a difference there is between them.

References:

http://www.sciencekids.co.nz/experiments/lightcolorheat.html

http://www.sciencebuddies.org/science-fair-projects/project_ideas/Phys_p030.shtml#background

http://www.physicsclassroom.com/class/light/Lesson-2/Light-Absorption,-Reflection,-and-Transmission

http://antoine.frostburg.edu/chem/senese/101/features/color-complement.shtml

http://en.wikipedia.org/wiki/Color

27 Comments

Candy Chromatography

Floating Egg

How does color affect heat absorption?

Archives

Tell us what interests you most, and we'll send you a free PDF of a lesson in that subject!

Categories