What do romance novels have in common with candy experiments? They're both full of sinking and rising hearts.
Cake Mate hearts float nicely for a few minutes when you put them in water. As they do, they dissolve, shedding bright red sugar solution. The solution, denser than pure water, sinks.
Conversation hearts sink immediately. In some hearts, however, trapped air bubbles seem to emerge, floating upwards, sometimes carrying up candy particles. (Watch the blue heart in the right side of the bowl shedding pieces which float up to the surface.)
I can feel my heart rising already, can't you?
Melted Gum
Note to self: next time I let my kids melt gum on a baking sheet, put down tinfoil! I keep forgetting this tip I've seen my readers use, and it would save me hours of work. I still haven't gotten all of the gum off.
Chromatography Methods
The theory of chromatography is simple: you dab a dot of color onto a paper, stand the paper up in water, and let the rising water separate the colors by solubility. But how do you make sure the paper stays upright?
One easy method is to crease the chromatography paper vertically, then stand it in water. This works especially well if the bottom of the paper is cut flat (an angled bottom will make the paper tip.)
If the paper doesn't stand on its own, try folding the top of the paper over the side of the glass. Note that that this method is problematic: a professional biochemist cautioned me that surface tension between the glass and the paper might interfere with the capillary action causing the water to rise. However, it works well enough for M&M color separation, or the other basic chromatography we do in our kitchen. For better results, angle the bottom of the paper out so that the paper is not stuck to the glass.
If your chromatography paper is especially difficult to work with, clip it in place with clothespins or binder clips. Lay a pencil over the top of the glass and clip on the paper, forming a T with the paper hanging down, or take a shortcut and clip it to the side of the glass, as shown (angling the paper out from the glass, as above).
When doing chromatography with large groups, I use clothespins on a wire rack to suspend the chromatography papers over a dish of water. This way I only need one water container. (Make sure your scientists label their papers in pencil if they want to know which are theirs.)
Whatever chromatography method you use, make sure that the color dot is placed above the waterline. This is easy if you're hanging the paper--just hold the bottom edge in the water with the dot above the surface, then clip the paper in place. If you fold and stand your paper, make sure the dot is high enough so that it will still be dry when you stand up your paper. Then watch the water rise, and see what colors your dot is really made of.
One easy method is to crease the chromatography paper vertically, then stand it in water. This works especially well if the bottom of the paper is cut flat (an angled bottom will make the paper tip.)
If the paper doesn't stand on its own, try folding the top of the paper over the side of the glass. Note that that this method is problematic: a professional biochemist cautioned me that surface tension between the glass and the paper might interfere with the capillary action causing the water to rise. However, it works well enough for M&M color separation, or the other basic chromatography we do in our kitchen. For better results, angle the bottom of the paper out so that the paper is not stuck to the glass.
If your chromatography paper is especially difficult to work with, clip it in place with clothespins or binder clips. Lay a pencil over the top of the glass and clip on the paper, forming a T with the paper hanging down, or take a shortcut and clip it to the side of the glass, as shown (angling the paper out from the glass, as above).
When doing chromatography with large groups, I use clothespins on a wire rack to suspend the chromatography papers over a dish of water. This way I only need one water container. (Make sure your scientists label their papers in pencil if they want to know which are theirs.)
Whatever chromatography method you use, make sure that the color dot is placed above the waterline. This is easy if you're hanging the paper--just hold the bottom edge in the water with the dot above the surface, then clip the paper in place. If you fold and stand your paper, make sure the dot is high enough so that it will still be dry when you stand up your paper. Then watch the water rise, and see what colors your dot is really made of.
CakeMate Hearts
If you're not making cupcakes, there's only so much you can do with Cake Mate Valentine's hearts. After we had eaten our fill of the hearts a kind neighbor gave us, I wondered what we'd do with the rest. "How about candy experiments?" a friend suggested. Of course.
According to the label, these red hearts actually contain three dyes: Red 3, Red 40, and Yellow 6. When we tried chromatography, the red heart dye separated into at least two different colors, a pink and an orange.
If the color table on www.red40.com is accurate, we found Red 3 ("cherry-red") and Red 40 ("orange-red"). Yellow may have been too faint for us to see (this is common), it might not separate from the other dyes in water (for instance, if it moves at the same speed in water as one of the other dyes), or it may only have been used in the pink candy which we did not test.
We also wondered if the hearts would sink or float. Turns out they do both.
These two hearts were put in water at the same time. One sank quickly, while the other floated for several minutes. The floating heart had an air bubble trapped underneath, which probably helped the buoyancy.
Overall, the hearts floated at first, then sank, then returned to the surface as a dissolving mass of bubbles.
Easter Blue M's?
Easter M&Ms come in such pretty colors that when we got some last year, we were excited to experiment with them. Sadly, the M&M colors were too faint for good chromatography--we could hardly see the colors on the paper, much less any separation. So this year, we decided to concentrate on the m's themselves.
First of all, are these m's made of the same stuff as normal white m's? Experimentation shows at least one difference: these m's seem to dissolve.
What about the speckles on the M&M eggs?
Yes, they float too.
Which leads me to my final question: how do they print the speckles on all sides of an oblong egg? Alas, experimentation can't answer that one.
First of all, are these m's made of the same stuff as normal white m's? Experimentation shows at least one difference: these m's seem to dissolve.
Blue streaks sinking down from the bottom of the m--dissolved blue dye?
That led us to the big question: do the blue m's float? What about all those little bunnies and sheep? Apparently so.
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What about the speckles on the M&M eggs?
Yes, they float too.
Which leads me to my final question: how do they print the speckles on all sides of an oblong egg? Alas, experimentation can't answer that one.
Do hearts float or don't they?
As I wrote previously, I've been wondering why Valentine's conversation hearts float if you leave them in water. My theory was that formation of air bubbles on the surface of the hearts made them float. So how could I test it?
Water has air dissolved in it. This air forms the bubbles you see when you start to heat water (as opposed to the bubbles formed by water vapor when water boils).* You can remove most of the air by boiling the water. So I boiled a pan.
After the pan had returned to room temperature (I helped it along by letting the full pan of hot water sit in a cold water sink), I filled cups with 1/2 cup each of normal tap water and boiled water. Here's what happened:
In my tap water cup, bubbles quickly developed on the hearts. In my boiled water cup, so few bubbles formed initially that I could still count them. Two of my tap water hearts were floating within an hour.
The hearts in boiled water, on the other hand, took much longer. It was an hour and a half before one of the hearts was finally covered with enough tiny bubbles to start floating.
Why did the heart in boiled water float at all? Because even though I boiled the water, the water was continually exposed to air. I couldn't remove all the air unless I tried the process with vacuum equipment--which I don't have in my kitchen!
*For more information, visit The Engineering Toolbox.
Water has air dissolved in it. This air forms the bubbles you see when you start to heat water (as opposed to the bubbles formed by water vapor when water boils).* You can remove most of the air by boiling the water. So I boiled a pan.
After the pan had returned to room temperature (I helped it along by letting the full pan of hot water sit in a cold water sink), I filled cups with 1/2 cup each of normal tap water and boiled water. Here's what happened:
In my tap water cup, bubbles quickly developed on the hearts. In my boiled water cup, so few bubbles formed initially that I could still count them. Two of my tap water hearts were floating within an hour.
Floating hearts covered with bubbles.
The hearts in boiled water, on the other hand, took much longer. It was an hour and a half before one of the hearts was finally covered with enough tiny bubbles to start floating.
Why did the heart in boiled water float at all? Because even though I boiled the water, the water was continually exposed to air. I couldn't remove all the air unless I tried the process with vacuum equipment--which I don't have in my kitchen!
*For more information, visit The Engineering Toolbox.
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