So, today 22 Grade 1's and 2's came to my lab.
So what to do? What to do? That's a lot of kids in a full on laboratory settng. I've written about this activity before, but here goes again.
Thankfully, this is where ScienceBlogs rocks, since I had happened upon an awesome post by Janet over at Adventures in Science and Ethics that was all about the simple act of "just adding water" to see what happens.
The only difference here, of course, is that we got to do it at a real lab, so it was wonderful to see the kids get a real hearty dose of science culture as it were.
As well, just to make it a little more science-y, I presented the experiments as a mystery of sorts. One where my colleagues in the building inadvertantly switched some chemicals around, and it was the kids' job to figure out which chemicals were which.
How would they do that? - well, just by adding water and noting what happens to the chemical. And what was doubly cool (at least, I thought this was cool), was that I presented the chemicals as being one of 5 possibilities:
Sodium Chloride (table salt)
Sodium Bicarbonate (baking soda)
Glutenin (Rice Flour)
Amylose (Corn Starch)
You'll note that I took a full on chemical name for the principle component of said kitchen ingredient. This way, I think I was able to convince the kids that this was real high tech science all the way.
Anyway, it was great fun, and below is a copy of the slide show I used to show the kids what the chemicals are suppose to do (note the image of sodium bicarbonate is actually only carbonate, but I couldn't find a good pic the night before). Also the picture of the Falcon tube at the end is just to show them how they can measure their water amounts.
That corn starch stunt is amazing. Score one for non-newtonian liquids, but what was even more awesome is that given the structure of things like amylose, it totally makes sense why it would behave like that.
That is awsome! Do you mind if i steal the concept for some possible future teaching event? :-)
No, of course, not. Here's some amounts of the powder and the amounts of water you'll need to see the effects.
H + 5ml water (1.0ml collagen) - this one might actually work better if you had the water and then add the collagen a little bit at a time. Vortexer was a bit hit!
A + 4ml water (2.0 - 2.5ml NaCl) - this is toughest one to get working, since the icecubes need to be pretty dry feeling (i.e. in a class scenario, it's tough to hand out very fresh icecubes in one go). If they're a little bit melted the string tends to not stick very well (maybe just try adding the salt as powder)
B + little bit of water at a time (1.0ml sodium carbonate) - bubbles can be hard to see with water. If you think you can negotiate the use of vinegar in class, then the bubbles are way more observable.
C + 4ml water (15ml glutenin) - kids like the mortar and pestle. This one works pretty well all the time.
D + 4ml water (7ml amylose) - might be best to add 3ml first and then finesse the water until consistency is just right.
Hope this helps.
I find you can't go wrong with dry ice. Plus, you can add a bit of bromophenol blue to water, drop in a little dry ice and make it change color.