February 21, 2012

Swirling Colors Milk (science experiment)

Who would have thought you could do such a colorful science experiment with milk?  We had fun at our Super Science Party adding a "secret substance" that would turn a tray full of milk and food coloring into a swirling symphony of colors!



Here's what you need:
  • milk (whole or half and half ~ skim won't work)
  • tray or shallow bowl
  • food coloring
  • cotton swabs
  • liquid dish soap (Dawn works well)
Here's what to do:

  1. Pour some milk into your tray.  You'll want it at least 1/4" deep.
  2. Add several drops of food coloring near the center of the tray.
  3. Dip a cotton swab into the color (don't stir it, just dip!).  Nothing really happens.
  4. Now, dip your cotton swab into your liquid dish soap and then dip back into your milk.  (again, don't stir, just dip it in and hold it in place for a few seconds!).  Watch how the colors "jump" away from the soap, and then begin swirling around on their own!

 Look at all the fun we had at the party.



Here's the science behind the swirling colors.  (From Steve Spangler Science)

"Milk is mostly water but it also contains vitamins, minerals, proteins, and tiny droplets of fat suspended in solution. Fats and proteins are sensitive to changes in the surrounding solution (the milk).

The secret of the bursting colors is the chemistry of that tiny drop of soap. Dish soap, because of its bipolar characteristics (nonpolar on one end and polar on the other), weakens the chemical bonds that hold the proteins and fats in solution. The soap's polar, or hydrophilic (water-loving), end dissolves in water, and its hydrophobic (water-fearing) end attaches to a fat globule in the milk. This is when the fun begins.

The molecules of fat bend, roll, twist, and contort in all directions as the soap molecules race around to join up with the fat molecules. During all of this fat molecule gymnastics, the food coloring molecules are bumped and shoved everywhere, providing an easy way to observe all the invisible activity. As the soap becomes evenly mixed with the milk, the action slows down and eventually stops.

Try adding another drop of soap to see if there's any more movement. If so, you discovered there are still more fat molecules that haven't found a partner at the big color dance. Add another drop of soap to start the process again."

Sharing this swirling good time at:

9 comments:

  1. This is so neat! I had to show it to my science guy husband! We don't buy regular milk, but I'm guessing this won't work with soymilk! :) I pinned it anyway! May have to buy some regular milk just for this!

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  2. It really is neat! I'm not sure about the soymilk because I know it has to do with the fat content, but it would be worth it to pick up a pint or two of regular milk to give it a try.

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  3. this party is amazing!! my son would be so into it. we love themes here too... may be borrowing your ideas! :) thanks!

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  4. I just did this with my boys! Such a cool easy experiement! Thanks for sharing!

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  5. Love the experiment! Just FYI, in Argentina this experiment doesn't work with regular milk. I once tried it at home with skim milk and it worked great, when I took it to my classroom I though: 'if it worked with skim milk it will work much better with regular milk because it has more fat...' DOH! Don't know why it didn't work at all. The teacher in charge of the science lab in my school told me she didn't know why either, but she had found the same problem some time before.

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    Replies
    1. that is against science :)
      it should work better in more fatty milk.

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  6. This is one of my favorite experiments because it is so easy yet is so captivating. We really appreciate you liking our experiments and linking back to us - Like It? Link it. Not all bloggers are as responsible. I'm pinning all of your experiments to our board - http://pinterest.com/stevespangler/steve-spangler-science-in-action/

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  7. This also works if you put tiny drops of water on wax paper...(not sure if you can add food coloring) the water instead of like spreading will stay together and form tiny little balls of water. You can roll them around and have fun with them. Then if you touch the water with a toothpick dipped in dish soap it all starts spreading. It's actually pretty fun too...it entertained a lot of seniors in my a.p bio class last year. Haha :-D

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  8. My grand daughter did this experiment a couple moths ago via YouTube . At the time we did not know the science behind the swirling of the colors in the milk. I happened upon your website this morning and read your explanation and wanted to ask for your permission...may I add the explanation to her video? I hope to receive your reply soon. Thank you so much for helping to get today's youth interested in science in a fun and engaging way!
    Sincerely, Deborah

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