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Why is it that when you pour koolaid into water, it sinks, but if you stir it up it mixes and never sinks again?
Question Date: 1998-01-23
Answer 1:

When you pour the kool-aid into water, the little crystals go straight to the bottom because they are heavier than the water. If you left them there without stirring, and came back a few days later, you wouldn't see any crystals on the bottom. That's because the stuff in kool-aid can DISSOLVE in water, which means that each little molecule of kool-aid gets suspended between the molecules of water. When that happens, you can't see the kool-aid anymore...it's trapped between the water molecules. When you stir kool-aid, you help DISSOLVE the kool-aid in water by keeping all of the crystals off the bottom and in the water. So you see, stirring kool-aid speeds up the dissolving,

Answer 2:

Are you referring to Koolaid in the granular form?If so the koolaid grains sink in water because the grains have a greater density than that of water. Once your stir the grains dissolve and go into solution where they remain because the dissolved koolaid is miscible with water unlike oil (floats) or gasoline (sinks). How long did you let the koolaid remain in the water before you stirred it? I would think that if you left it undisturbed for a long time (days) it would eventually mix on its own.

Answer 3:

I'm not a chemist, but I think I can answer your question about Kool-Aid. Kool-Aid is mostly sugar, which is heavier than water, so when you pour it in it sinks to the bottom. When you stir it up the sugar (and flavoring) dissolves so that you don't have any solid particles any more. Stuff that is dissolved in water will not sink because it is no longer a physically separate thing. It becomes part of the water (or water-sugar-flavor solution). What happens if you pour the Kool-Aid in but don't stir it? Will it eventually dissolve? You may have to wait a long time, like over night. Try it and let me know what you find!

Answer 4:

It all has to do with the rate at which kool-aid crystals (basically its SUGAR!!) dissolves in water relative to the rate at which the sugar crystals sink. If you just dump the stuff in, it sinks because it is denser than the water. As it sinks it dissolves. But when you stir the water, the rate of dissolution becomes greater than the rate of sinking and so the crystals dissolve before they reach the bottom. So it all has to do with the comparison between the rate of sinking versus the rate of dissolution.

Now I have an experiment for you. What happens if you mix up some Jello and instead of letting it sit still, you keep stirring it??? WILL THE JELLO EVER SET??
You may have to borrow your mom's mixing machine because you will get tired of stirring after 10 minutes!!!!

If you do the experiment let me know how it turns out. Actually, you should set up a control. Make two batches of Jello...with one, put it in the refrigerator and dont stir; with the other, keep stirring it (in the refrigerator), if you can figure how to arrange that without your mom or dad getting mad!!!

Answer 5:

Materials sink in water if their displacement is lower than an equivalent amount of water. i.e. a ship floats because the total volume of water that must be moved aside to sink the ship actually weighs more that the ship. Another way of looking at it-- when the ship is afloat on the water, if it moves down then more water is displaced-- and this water pushes back on the ship-- keeping it afloat. If, however, the ship is pushed into the water so that it can fill -- it will sink quickly since it now weighs far more -- and more than the water outside.

In you question, Kool-aid is a mixture of several compounds -- among them sugar, citric acid, and food coloring. Each of these components is denser than water -- so they will sink when added. However, when stirred, many of the components dissolve in water -- i.e. they either form compounds with the water or they are broken into very small molecules of the substance. These new molecules are so small that to them the water is more like a bag of ping-ponk balls which is being shaken. In such a bag, a slightly heavy ping-ponk ball will tend toward the bottom -- but only a very heavy one will stay on the bottom. (The ping-pong balls represent individual water molecules). Most of the Kool-aid compounds are small enough to remain suspended.

However, given a long time, the heavy components will fall to the bottom of some mistures -- for example, the bright green plant dye chlorophyl will make a green solution -- but will sink to the bottom of some solutions in a period of a couple of days.

The issue is complicated by surface tension-- if you look closely at the Kool-aid powder as it is added to the water -- some small pieces will stay on the top of the water even though they are denser than water. This is easy to see if you drop a tiny amount of corn-starch on water -- it will sit there on the top. In this case, the water won't easily wet the surface of the material, and the surface will not bend in a very sharp angle -- so the material is bouyed. Of course, if the material dissolves, it will eventually sink... See if you can see this.

Answer 6:

The koolaid powder are little crytals which are bound to each other. When you stir them up, you encourage the bonds between the molecules to break and the molecules go into the water. If you don't stir, but wait long enough (assume the water doesn't evaporate) what will happen then?

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