I don’t think I’ll be doing those. Besides being dangerous, they’re also too noisy.
Yes, and yet no. The experimental method is extremely important, and much more important than any science demo. That said, a science demo can be really cool, and inspire a kid to want to know more. If you’re doing it right, you can gently nudge the kid down the path that leads to the demo you know will work, and they’ll feel like they’ve gotten a big bang for their buck, and investigated a question they developed - and they did, with guidance.
When you try to teach the scientific method to kids in a short period of time, they usually come up with untestable hypotheses, and you spend most of your time trying to narrow it down to something do-able.
I use a combination of the two approaches with Attacklass and Attacklad: demos that I know will be cool, that I can pose as interesting questions, and help them develop the ideas, as well as actual hypotheses where I don’t know the answers, and we do small experiments, or else gedankenexperiments to sort out (why are the cigarette butts in the dog water bowl outside the bakery aligned in parallel? is it random? is it due to the water dripping in the bowl? what will happen if we perturb them? Dad, I’m wet, can we go in now? )
Originally posted by Attack from the 3rd dimension: “why are the cigarette butts in the dog water bowl outside the bakery aligned in parallel?”
This suggests a series of excellent experiments: How the hell do Canadian Dogs light their cigarettes ? Do they have thumbs so they can use those little Bic lighters ? Why do they put their cigarettes out in their own water bowl ? Are they just about to leave for Chicago and are thinking: “I’ll never drink here again, screw them other dogs.” Do other dogs come by later and think: “Yuck, cigarette butts in the water bowl . . . maybe if I push them all so they are aligned in parallel I will be able to drink around them.”
Originally posted by Sage Rat: " I protest !"
The OP didn’t ask for a science project, but for “ideas on science experiments/demonstrations” We’re just a little heavy on demonstrations and a little light on experiments.
And I perhaps didn’t make it clear earlier that I was maybe a bit obsessed with tiny electric motors. . . so you could ask me for make-up tips that you could give your eight-year-old niece and I would probably answer: “I don’t really know anything about make-up, but here are some websites for tiny electric motors that she might find interesting.”
You can isolate DNA from wheat germ using easily available materials. Here’s the protocol (note: the measures aren’t exact and don’t need to be).
Add about 1 Tbsp of wheat germ to about 1/2 cup of water. Add one pump of liquid hand soap (or a squirt of dishwashing detergent) and a few shakes of meat tenderizer. Stir to mix (try not to create bubbles) and allow to sit at room temp for 5 min or so. The wheat germ should settle to the bottom. Transfer the liquid to a new, clear container with a lid. Try not to carry over any of the wheat germ. Add an equal volume of isopropanol and mix by inverting. You should begin to see white strings forming. That is the DNA. The more you mix, the more DNA will precipitate.
The science: The soap disrupts the cell membrane of the wheat germ. The meat tenderizer is an enzyme (papain) that cuts up proteins. With disrupted membranes and cleaved proteins, the cell can no longer stay together and it breaks up, releasing the DNA into the solution. The isopropanol then causes the DNA to precipitate out of solution. It is a very long, sticky molecule, so the precipitate looks like a string that clumps together.
You can also use this demonstration as an opener to talk about DNA and genes and heredity, etc.
They use Zippos, when they aren’t deflagrating* grain elevator models.
That’s cats. Dog’s are pack animals, and care for other dogs. A cat is just an empty vessel for demons to inhabit.
I don’t think they’re that discriminating, I don’t think cigarette butts would bother them at all.
There is a dog bakery in town here - it doesn’t bake dogs, but rather makes gorgeous looking goodies like cupcakes with bone meal and other dog-appropriate ingredients - this for a species whose members routinely sniff each others asses in greeting, and drink from the toilet.
- “exploding” for those not in the know. Doesn’t it sound like the admiral is being demoted?
Take a fluorescent tube in your hand and rub it with fur or silk and it will light up. (Please, no remarks about your tube lighting up Santo).
You need this website. Okay, you don’t need it, but it’s really cool and has lots of stuff like this on it.
Or take a soda or beer in a clear glass bottle and sub-cool it in a salt/ice bath. While it’s still in the liquid state pop the top and observe the spontaneous crystallization of the fluid. If you pop it too soon, you can stick something into the bottle or just take a sip, which will introduce nucleation sites and the crystallization will start at those points.
Finally you can do what my former neighbors did at their kid’s 5th birthday party. Let the kids make super-conductors, bake them in the oven, put them in liquid nitrogen and float magnets over them. I am not joking. The actual hit of the party though was freezing bananas in LN and hammering nails into trees with frozen banana hammers.
Ink volcanoes! (it is a lot less messy than it sounds)
Just warm up a bit of water with china ink (or food coloring, really), put it in a small bottle with a small opening, and dunk this inside a larger container with cold water. The colored water goes to the top as it is warmer. Then you try it with all different combinations of temperatures and explain convection.
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I don’t know your location, but this might be a bad time of the year for seeds or tadpoles, which are mandatory 8-yo science teaching.
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Making inks separate is also fun. Just make a fat blot with a black/brown marker in an end of a paper towel and dip that end in water or alcohol (depending on the type of ink). The ink will run, but it different colors will separate at different speeds, so you will see the components. It is cool seeing how different brands of marker separate differently.
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Layering liquids of different densities is also fun. Water, alcohol, juice, oil, etc. Color them for better contrast.
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ETA: Oh, and filling a regular rubber balloon with water and taking a lit match to it. The rubber shouldn’t burn as the water absorbs the energy.
Skinner box?
How about dyeing flowers with food coloring. It lets you explain capillary action and transpiration and it’s pretty!
When my mom taught 4th grade science, she used a book called Science Experiments You Can Eat (can be found on Amazon for less than $10). It had some fun stuff in it, with basic explanations.