Family Science
Candy Chromatography
June is National Candy Month. While this might sound like an excuse to eat a bunch of lollipops or chocolate bars, there are other ways to celebrate. For instance, many science experiments involve candy. Follow the directions below to find out how you can use science to determine how candies get their colors.
Materials:
Coffee filters
Clear jars or cups
Pencil
Tape
Scissors
Measuring cup or pitcher filled with water
Colored candies (M&Ms, Skittles, or Reese’s Pieces work well)
To Do:
1.) Cut the coffee filters into several strips. Each strip should be about 1” wide and just slightly longer than the height of your cup or jar.
2.) Fill one cup with a small amount of water.
3.) Choose one of the brown or purple candies.
4.) Dampen the candy by briefly dipping it in the water.
5.) Shake off any excess water and then smudge the candy on one of the filter strips, approximately 1” from the bottom.
6.) Fold the opposite end of the filter over a pencil and secure it with a piece of tape.
7.) Lay the pencil across the top of a second cup so that the strip hangs down inside the cup.
8.) Use a pitcher to carefully add enough water to the cup so that the water just touches the bottom of the filter strip. The water should not touch the candy smudge.
9.) Now watch closely as the water begins to travel up the filter paper. What do you notice? What happens when the water reaches the candy smudge? Keep watching for several minutes. Do you see any other colors on the filter?
10.) When the water reaches the top of the filter paper, remove it from the water and set it aside to dry.
11.) Repeat steps three through nine with some of the other candies.
Now Try This:
Repeat the investigation with different types of candies. Do you get the same result? What might happen if you dissolved a small amount of salt in the water? Try it and find out.
What’s Going On?
Look closely at the list of ingredients on a bag of M&Ms or Skittles. In addition to traditional ingredients, like chocolate and sugar, you may notice Red 40 or Yellow 6. These are the dyes that give the candies their colors. By using a process called chromatography, you can determine which dyes were used to make the different candies.
Chromatography is a method for separating mixtures, such as candy dyes, into individual parts. In this case, the separation is accomplished by using a coffee filter and water. As the water travels up the filter, it carries the dyes along with it. Different colors of dye travel at different rates due to their size, their solubility, and their attraction to the filter paper. The color molecules that are the most soluble in water or that have the least attraction to the paper travel up the paper the fastest. Those color molecules that have less solubility or that are more attracted to the paper travel more slowly.
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Debbie DeRoma is the Education Manager at the Reuben H. Fleet Science Center.
Egg-ceptional Science
With the Easter Bunny scheduled to make his deliveries this month, there is a good chance you have a few extra eggs in the refrigerator. If you get tired of eating all these eggs, you can save a few for science experiments. Be warned—this investigation takes a few days. You will need a little patience, but it’s definitely worth the wait.
Materials:
Raw egg
Clear jar or cup
Vinegar
Refrigerator
To Do:
1.) Place the egg in the cup and cover it with vinegar.
2.) Look closely at the surface of the egg. What do you notice? You may see bubbles forming on the outside of the shell.
3.)Place the cup with the egg in the refrigerator for 24 hours.
4.)On the second day, carefully pour the vinegar into the sink.
5.) Now, cover the egg with fresh vinegar and return the cup to the refrigerator.
6.) Leave the cup in the refrigerator for another six to seven days. You can check on the egg periodically, but don’t disturb it too much. Be sure to pay attention to the bubbles coming off of the egg.
7.) After a week, remove the cup from the refrigerator and carefully pour off the vinegar.
8.) Gently lift the egg out of the cup and rinse it with water. What do you notice? What happened to the shell?
Now Try This:
Repeat the investigation with a hardboiled egg. What do you notice about the texture of the egg after it sits in vinegar for a few days? Would you get the same result if you used another type of liquid such as lemon juice or soda? Try it and find out!
What’s Going On?
The egg’s shell is made of calcium carbonate. This is what makes the shell hard and gives it its strength. Vinegar is actually a type of acid, called acetic acid. The vinegar reacts with the eggshell, causing the shell to break down. This chemical reaction produces the carbon dioxide gas bubbles that you see on the surface of the egg. Once the shell is completely gone, the only thing that remains is the delicate membrane of the egg. Some of the vinegar actually enters this membrane, making the egg a bit bigger. If you try this investigation with a hard-boiled egg, you will notice that the egg feels very rubbery.
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Debbie DeRoma is the Education Manager at the Reuben H. Fleet Science Center.
Straw Gliders
The next time you visit the beaches near Torrey Pines or La Jolla, be sure to look up at the sky. You may notice many colorful gliders soaring high above the ground. These gliders provide the ultimate in “green” flight. Unlike airplanes and helicopters, these simple machines allow people to fly using only air currents. Try the activity below to learn more about glider design and flight.
Materials:
drinking straws
clear tape
ruler
construction paper or card stock
pencil
scissors
To Do:
1.) Use your ruler to measure and mark a strip of paper that is 1” wide and 8 - 10” long. Carefully cut out this strip.
2.) Tape the ends of the strip together to make a large loop.
3.) Now, measure and mark a second strip of paper that is 1” wide and 6” long.
4.) Carefully cut out this strip and then tape the ends together to make a smaller loop.
5.) Use tape to attach the small loop to one end of the straw.
6.) Attach the larger loop to the opposite end of the straw. Make sure both loops are on top of the straw.
7.) Find a clear space to test your glider. Hold the glider in the middle of the straw, with the small loop in front. Throw it gently. How far did your glider travel?
8.) Take a look at the different parts of your glider. What parts do you think you could change to make it soar farther?
9.) Modify your glider (or make a new one) to test your ideas.
Now Try This:
Would your glider fly differently if you changed the size of the straw or taped two straws together? What if you shaped the loops into triangles or squares instead of circles? Try it and find out!
What’s Going On?
If you throw a plain straw, it doesn’t travel very far. Yet, when you add paper loops, the straw glides through the air. This is because the loops act like wings. Just like a bird or airplane, the wings on your glider help it to stay aloft. The difference in air pressure above and below the loops creates what is called “lift.” Air flows over both the top and the bottom of the glider and meets at the edge. Since the air flowing over the top of the wing has farther to travel, it moves faster. This creates a difference in pressure. As the higher and lower pressure airflows move toward each other, the glider lifts up.
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Debbie DeRoma is the Education Manager at the Reuben H. Fleet Science Center.