You could talk about the surface tension of water and the activity would be:
1. Give everyone a pipette and a small glass of water.
Place a penny on a napkin and guess how many drops of water they can get on top the penny before the drop burst.
After they make their guess have them do the experiment.
2. You could also give everyone one of the fortune telling fish and talk about why it curls or does not curl.
It curls up because of the moisture(water) in your hand. Some will guess heat, or electricity. You can order the fish from oriental trading for little cost.
Ruth Woodall, Director Tennessee Scholars
611 Commerce St. Suite 3030
Nashville, TN 37203
Have a blessed New Year.
Two thoughts off the top of my head:
1. Educational Innovations sells a large variety of materials and equipment for science demonstrations, and I've bought a lot from them in the past (their prices seem quite reasonable). See: http://www.teachersource.com/
2. Since almost everyone carries a cell phone with a camera, how about a social activity involving photography and chemistry? I haven't thought this through, completely, but ideas might be a competition to photograph chemistry in action, or to give people a bunch of clues that they then have to find the evidence for (documenting their find with a photo). E.g., "Find 5 things that contain cellulose" or the like. Winners' photographs could be downloaded at the end of the event and projected on a screen.
Hi Ruth! You and Bryan have some fun ideas. I like the drops of water on a penny. It’s not too hard to add an extension--drops of salt-water on a penny. You actually get more drops of a saturated saltwater solution on a penny than drops of tap water. And comparing the amounts is fun, too. I’ve noticed that there are many variables going on here, if the penny is heads or tails, whether it’s dirty or clean, etc…but it does lead to a nice discussion of why sodium and chloride ions in the mix causes Lincoln’s head to look so big.
I also like the fortune telling fish mainly because it is so easy to pull off in a large group setting. Also, it’s really inexpensive! You could easily give each attendee their very own red cellophane fish. Would you really trust the “opinion” of a piece of red cellophane? There’s no way a scientist would for a second, so they’ll want to find out what’s going on. I’ve seen this work so well at a public event—you were probably at that very same event in Atlanta, Ruth. I may be able to find a write-up of the investigation and explanation somewhere.
If you’re looking for inexpensive chemistry-related stuff that people love, I have to say that those self-inflating mylar balloons <http://www.joissu.com/prodinfo.asp?number=43-712> from Joissu.com (like Oriental Trading) have been more popular than I ever envisioned. I knew that kids would love them, but I had a group of grad students a few months ago who each had to have their very own! There’s a packet of citric acid and a tablet of baking soda inside each. You rupture the little packet of water by slapping or stepping on the balloon and it starts to inflate. The balloon gets cold, too. Nothing like an endothermic gas-producing chemical reaction to make people smile--especially when it’s all contained inside a shiny happy balloon.
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Thanks for the great suggestions. I will have to look into the sites you suggest for ordering materials. I have also considered a scavenger hunt (example clues: find something containing oxygen; find something with density less than 1 g/mL, etc). Answers can be submitted via photographs or in writing. We could give prizes for most creative answers and most clues completed.