Mystery Science, Part I: How to Set Up A Footprint Demonstration & An Experiment to Test for Starch

The footprint demonstration is the messiest part of this mystery.

If your children are participating in this mystery, depending on their age, you might want to help them to begin to understand the distinction something we can directly observe and know for certain (evidence) and the conclusions we draw or "infer" from the evidence (inferences). Each week the scientific test (which they can watch us do, or do themselves) will give them clues to indicate a few of the suspects. Have them decide which ones and put a check beside their names. Once our mystery is complete, they can then look over all the clues and they should see that one suspects stands out as being included in all or at least most of the clues. They can then conclude that this person is the most likely suspect and suggest their arrest. If you want to just follow our experiments, then you can go to this right now, or you can stay here and see how to set up the experiments in your own house. You can also do a mixture -some you do at home, some you see on this blog. It is up to you.

Now, on to this week's clues...
Footprints

Paint the bottom of the shoe.

Step firmly onto a clean sheet of white paper.

You may not capture the entire print. That is okay.

This is probably the messiest of the demonstrations for this mystery, so you may want to just follow along with ours with this one. If you choose to set this one up, you will need seven sets of shoes, long strips of paper (we used banner paper), some sheets of white paper, some washable paint and a room you don't mind getting paint on the floor. No matter how hard you try, you will end up getting paint on the floor. First, for each print, you will paint the bottom of the shoe with the washable paint and then step firmly on the white paper. It will leave a print, but it will not necessarily leave the entire print. Once you have done this for all seven sets. You can then assign them to our different suspects (Mrs. White, Miss Scarlet, Mrs. Peacock, Col. Mustard, Prof. Plum and Mr. Green, plus another mystery person....yes, these names should sound familiar to you.) If you have several people in your family, having older children help out with this will work nicely. That is what we did. To make the paint even more washable, we squirted in some dishwashing liquid in the paint.

Now you will need to make part of the crime scene for them. Spill a little puddle of your paint on one end of your paper. Now, using the shoes you assigned to Mr. Green, have this person walk through the paint puddle and on down the paper. Using the person you assigned the shoes to Miss Scarlet and our mystery person have them walk through the puddle, but have them carry something between them so that one of them is walking backwards. Lastly, using the person you have assigned Mrs. White, have her run through the paint and run back. We actually could not tell who did what when we looked at the footprints, but it did help to keep it looking authentic, and who knows? Perhaps your sleuths can tell more from the crime scene than we could!
You can clean up everything now.
Once everything is dry, show your sleuths the samples from all the suspects.  (There will not be one for the mystery man.) See if they can determine which prints are found at the crime scene. Have them check off the ones they find. Did they find the mystery man's prints? If they did reassure them that there was a set of prints not among the suspects and tell them that they may find out more about this suspect later. Did they find the right suspects? If not, do not fret. There will be plenty of clues that will point them in the right direction later.


The White Powders Test



For this test, all you will need is two cups that contain corn starch and one that contains baking soda. You will also need a container of  Iodine from the drug store.



Mark one of the corn starch cups...

and the baking soda cup with what they have in them.

Mark the second corn starch cup as the mystery powder.



For this experiment/test, you will need some iodine from the drugstore and some items from your kitchen to test.  How to conduct the Starch Testing can be found here. Once you are finished testing some items around the house, you can start the experiment for this part of the mystery. You will need two cups of about a teaspoon of cornstarch each and a third cup with about a teaspoon of baking soda. They should know just by its name that cornstarch contains starch, but have them test it anyway. They should see that the baking soda does not change the iodine's color but the cornstarch does. You student should correctly determine the identity of the mystery powder with ease. Can he figure out from the clues given in the story which suspects this points us to?