Science Buddies: "Ask an Expert"

I need a more cost effective suggestion to use in place of butter. Hair gel from the dollar store? I intend to do this with multiple classes of kiddos and cannot fathom the cost and waste of 50 groups worth of butter.





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Leave this to help the Experts:
The activity can be viewed at: How Do Arctic Animals Stay Warm?

Hi - a couple thoughts:

1. Will you be doing the experiment with multiple classes all at once? You should be able to re-use the bags between classes, so you might not actually need 50 groups' worth of butter.
2. I think the main point of the experiment will still get across if you just drop the butter and do empty bags vs air vs feathers. The kids will still feel a difference and you can still talk about how arctic animals stay warm, just with a focus on feathers/fur and not fat.
3. You could probably find a cheaper replacement - even just use water*, but with a class full of young students (as opposed to a parent doing this at home with a single student), I'd be hesitant to distribute ziploc bags full of gel/liquid anyway, unless you completely trust the students not to squish/accidentally (or intentionally) open the bags and squirt the stuff everywhere.

* I said water thinking that your body is mostly water anyway and therefore would have similar thermal conductivity, but upon Googling it, apparently fat tissue is only 10% water, so water wouldn't be the best option in terms of simulating butter. If you did want to get super technical about finding an equivalent replacement, you would have to look up the thermal conductivity of butter - available on pages like this https://www.engineeringtoolbox.com/food ... _2177.html - and then find a liquid/gel with a similar thermal conductivity. That page lists the thermal conductivity of butter as 0.2 watts per meter Kelvin, whereas water is 0.6, so water is ~3x more thermally conductive than butter. But again, per all the points above, it's probably easier to just not bother with the butter or a replacement.

Hope all that helps!

These are great suggestions! Thank you. I will likely just do one demo bag of butter for the whole group and skip it for small groups.

In that case, the only other suggestion/warning I can think of with a lot of students is the cool-down time between students sharing bags. A bag might feel "warm" from a previous student's touch if they're passing one around.

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