Pour some Milk in each of Two Saucers

Pour some Milk in each of Two Saucers
And keep a group of children (or adults) busy all afternoon
by Dr-J

We all know about milk.. It's white, It has calcium. You drink it. Children will come up with more ideas about milk than grown-ups, often. So, you put out two saucers (Paper cake plates work fine.) and pour the milk. Then what? Discuss the milk, and , then?

Take some food coloring, pretending the saucer is an analog clock face, drop a drop at 12, 3, 6 and 9. Do not stir. Don't even move it. And, please don't shake the table.

Okay, so the milk sits there. And the colors sit there, though, they do spread out a tiny bit. Now, take just one drop of an effective dish detergent (I use Dawn or Palmolive) and drop it in the center. Light show... I won't tell you what happens you have to watch.

The key to staying busy is to come up with a hypothesis or educated guess as to why what happens happens. Of course, you can search the web...but my experience is that you come up with the wrong answer, even from sites describing this activity.

So, let's make it a real experiment...what hypotheses did you have? The fat content? The calcium? Diffusion? There must be magnets somewhere? Oh, great, we have hypotheses. How can we test them? How can we make an experiment. You see for our first experiment, the plain milk saucer just sat there. And, we can compare the saucer with the milk and colors and detergent to it. But, it isn't identical except for one factor because two factors are different: colors and detergent. So how can we set up a controlled experiment where we check only one factor.

You think it's fat? How can you check? I have done a series of these tests and so, I know now. But for you to know, trust me, you can't just read it on the internet. I did find one correct answer out of about 6000 I found on the topic.

The point is, you are doing science because you don't know. And, when you are doing science, that's when it's fun. Of course you have to be confident that your ideas are good...as good as anyone's, and, you have to think about what you are doing and why. You have another hypothesis? What is it? Oh, you think it is because of the acid. Hmm. What acid is in milk? Do you know other household acids? Oh, lemon juice...yes, yes. I see, vinegar. Do they have anything in common with milk?

How many saucers do you have out now?

(c)2007 J S. Shipman
See also: http://www.thisisby.us/pour_some_milk_in_each_of_two_saucers

Pour some Milk in each of Two Saucers
And keep a group of children (or adults) busy all afternoon

Enjoy!!!



(c)2007 J. S. Shipman

Update 1 Oct 2012:
Here is a link to a video that might be used by students to think about what is happening in the science activity and experiments discussed in this blogpost:
http://evl.vcsd.k12.ny.us/safevideos/Video.aspx?id=VGoJuLX3BQQ (Paper clips floating Scott Thompson, Wisconsin Public School System, and, ExpertVillage.com (Source:  http://evl.vcsd.k12.ny.us/safevideos/ Video.aspx?id=VGoJuLX3BQQ, Accessed 1 Oct 2012)).  Can you think about how it might be related?

(c)2012 J S Shipman