Although we made it from A-Z in our Alphabet in Simple Science, I decided that I'd add some here and there.
Science Notebook Page (Click the picture to print).
I defined viscosity as how much a liquid resists flowing. High viscosity liquids flow slowly and low viscosity liquids flow easily. Usually thick things are high viscosity and thin things are low viscosity.
Making some Observations
To start off, I put some water in one cup and an equal amount of corn syrup in a second cup. I only filled the cups about a fourth of the way full, so that Xander could tip, swirl and play with the cups to make observations of the liquids. I asked him to describe what he was observing, then I asked which liquid had the higher viscosity and why. Water and corn starch are VERY different, so it was easy for him to come to the right conclusions.
Then I got out an art try and put 1 teaspoon of various fluids around the tray. We observed which ones spread out a lot, because they were able to flow easily (low viscosity) and which ones didn't spread out as much because the didn't flow well (high viscosity).
I had him choose which one he thought was the highest viscosity and the lowest viscosity.
Time to Test it Out
Then I had him test out his hypothesis. We picked four of the liquids, including the one he thought was the highest viscosity and the one he thought was lowest viscosity. We put a little blob of each at one end of the tray, then tipped the tray up to see which one made it to the other end first. While we just measured qualitatively to see which made it first, you could time it to bring in more math. However, if you're going to do that, maybe avoid the ketchup or mustard, they didn't flow very well at all. The mustard did more and the ketchup kind of all slid as a blob.
Xander must have really been missing out science experiments. Afterwards he asked what experiment we could do next! I'd better get thinking!