Praxis: Santa’s magic milk

By Patty Rooks on December 21, 2019.

praxis@praxismh.ca@PraxisMedHat

I can hear the excitement now! School is FINALLY out for the winter break and Christmas is only a few days away. Who wouldn’t be excited?! I know you don’t want to be bogged down with a lengthy activity this week but it involves Santa and, well, who wants to be on the naughty list this time of year? Let’s get started!

*Remember to ask an adult before doing this experiment.

Materials

– shallow baking dish

– small bowl/saucer

– red food colouring

– half-and-half

– Q-Tips

– Ultra Ivory Dawn dish soap

Procedure

1. The choice is up to you. Either you can leave the materials out with the instructions for Santa to do on Dec. 24. Personally, I prefer this option as it may get me some extra points with the “big guy,” or you can do it yourself.

2. Fill the shallow baking dish about half full of half-and-half.

3. Add four drops of food colouring. Make sure you space the drops out equally throughout the baking dish.

4. Place a few drops of the dish soap on the saucer. Dip just the tip of the Q-Tip into the soap.

5. Remove the Q-Tip from the soap and immediately place it in the centre of the baking dish.

6. Remove.

7. Observe.

8. Repeat if you wish!

What is going on?

You should have seen an explosion of colour swirling about before your eyes. The half-and-half is made up of mostly water, but it also contains a few other things that are vital to this experiment working. One is the high percentage of fat in the cream as well as the proteins. The science in this experiment tells us that the fat and proteins in the half-and-half are very sensitive to changes. When you add the dish soap to the half-and-half, the detergent lowers the surface tension of the half-and-half. This allows the food colouring to flow and swirl freely throughout the liquid half-and-half. The detergent also reacts with the protein in the milk, altering the shape of the molecules and setting them into motion. The reaction between the detergent and the fat forms what are called micelles. This is actually how dish soap helps get the greasy dirty grim off of the dishes. As the micelles form, the colours in the food colouring are pushed back and forth, around and around the half-and-half.

Happy holidays!

Patty Rooks, Senior Scientific Consultant PRAXIS, “Connecting Science To The Community”. Contact Praxis at praxis@praxismh.ca, http://www.praxismh.ca, Tweet or follow us @PraxisMedHat, or friend us on Facebook. Address: #12 826 11 Street S. E., Medicine Hat, Alberta, T1A 1T7 Phone: 403-527-5365, email: praxis@praxismh.ca.

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