Kuuliza si ujinga

I've been traveling a lot lately, mostly on work-related leave. Which means that I spent a good deal of time messing around in the lab at a friends' site. Productive? Well, some of our attempts were, and the biggest failure is a good story. Here's some of what I did.

1) Goats' blood
I've been invited to give a science presentation using local materials at a district science teachers' convention. I brainstormed with a friend and came up with what sounded like a great idea: extract DNA using soap, salt, and ethanol. Sound easy? We thought so. You just scrape the inside of your cheek, put the cheek cells in salt water, mix with detergent, and add ethanol. The DNA should precipitate beautifully at the ethanol-water interface.
We tried this first with cheek cells. No luck. We thought, maybe cheek cells don't have enough DNA. How about blood?
Now admittedly, red blood cells have no nucleus and therefore no DNA. But white blood cells should have plenty of DNA. We went to the butcher to request cow or goats' blood. The butcher was closed. We went back a second time; still closed. By this time, all the people in the area of the butchery knew we wanted goats' blood. But we figured we wouldn't be able to get it until the butchery finally opened the next day.
That night, there's a knock at the door. "I heard you wanted goats' blood." It's a guy carrying a cup of coagulated goats' blood. Er...yeah, we did want blood, let me go get a container. There was a jar of goats' blood in the refrigerator overnight, and we headed to the lab again in the morning.
As for the experiment? Still no luck. We tried it with goats' blood and pure ethanol and with Konyagi (the local hard liquor). We tried two types of detergents. Back when we were using cheek cells, we even tried a sketchy industrial alcohol we'd bought in town, which was purple and smelled like ashtrays. No luck all around. We sterilized the coagulated goats' blood with the purple alcohol, and dumped them both, with a good deal of relief, in the school trashpit.

2) Flower petals
Clearly, a different plan was needed for my science demonstration. We'd also read that you can make acid-base indicators by extracting the color from flower petals with alcohol. This one worked beautifully.
Take the petals of a local flower (I think we used bougainvillea). Combine with Konyagi or ethanol and crush with a mortar and pestle. Filter. You should have a pink liquid.
Add acid to this pink liquid. It turns slightly purple. Hmm. Not very exciting. Maybe it won't work, we thought.
But then! Add base (sodium hydroxide). Whoa! It turned yellow. A pink liquid made from flower petals, turning yellow when combined with something clear? That's cool! I think I have a science demo :-).