I did a 'Mr. Wizard' kind of lecture at our local middle school, I found out after I volunteered for a science demo the school put us in a large classroom with ALL the 5th graders, over 100 of them in one room! It was quite a large bunch. I did a thing about using things around the home for science demo's, like taking those styrofoam cups you get at Burger King and gluing a sonolert piezo pickup/transducer in the bottom and using RG174 (very small diameter coax cable), did some stuff with it, like showing it can be a microphone, I used a guitar amp which worked quite well, it made an acceptable mic. I also hooked it up to a Tektronix Oscilloscope, which I was able to project onto a movie screen by using a large double lens from an old rear projection TV, you could see the O-scope display quite clearly and I used it to project what the kids heartbeat looked like on the Oscope display, the output from the cup/mic was enough without amplification to sync the display onto the frequency of the heartbeat. That was some of the stuff I showed that day. I had quite a list of stuff, some of it I didn't have time to show. To pique their interest I had made a little stainless steel ball bouncer, I had some help from kids in the area making it, they loved helping. It used only stuff around the house, I used a soda can cut with scissors to make a contact when the SS ball (about 5 MM diameter) fell into the metal tabs, which closed a relay and switched 110 volt AC which was lowered quite a bit with a Variac, it turned out the magnet assembly I made, when I used 110VAC directly, shot the SS bearing into the ceiling! So I lowered the voltage to about 12 volts and the magnet was made with paper plates as the end pieces and a couple of Cm of toilet paper roll as the winding form, and quite a bit of magnet wire, I made an electromagnet very flat with lots of pancake shaped windings and a vertical orientied transparent plastic tube about 50 mm wide to confine the ball bearing and the bearing would bounce up and down with no apparent means of transport. I tried to get the kids to figure out what was going on.
I used a double sewing hoop, you know, the kind that women use to tighten the fabric for sewing, I instead used Saran Wrap in the loop and glued another one of those piezo pickups to it and said, see, this is a microphone... one of the teachers goes, "WHAT? How can that be a microphone?", which was well amplified because it was plugged into the guitar amp at the time, to much merriment🙂
A nice thing happened later, the teachers had each kid make me a little thank you note, saying which demo they liked the best, that was a blast getting all those nice notes from the kids later! I am planning my big comeback sometime this year!
Originally posted by AThousandYoungI've got an easy one for you if you are looking for ideas.
First of all, I didn't do this one because it made me uncomfortable (open flame 😕) and I only had 20 minutes. It was just one of a bag of tricks and I didn't have time for it. I did an oil and water demonstration (homemade lava lamp), a salt and soda demonstration, and vinegar and baking soda. I had more planned but I only had 20 mins and I didn't ...[text shortened]... demo for orientation, that's all. The students didn't need to take notes or anything.
This has to do with the ideal gas law PV=nRT I'm sure you all remember.
OK, take an empy coke can or some type of aluminum can. Put just a teaspoon or so of water in it. Heat it up on a burner until the water is boiling (water vapor). Quickly take it off the burner and invert it into a shallow dish of ice water.
The can instantly implodes upon itself due to the dramatic temperature change. Since the can is inverted, no gas can enter through the opening so the can has to crush itself to follow the ideal gas law.
The kids should be able to calculate the volume change based on the temperature of the water vapor (approx. 100 C) and the temperature of the water bath.
🙂
Originally posted by mlpriorThese kids aren't going to be calculating stuff with the Ideal Gas Law. That's high school I would imagine. These are 6th graders.
I've got an easy one for you if you are looking for ideas.
This has to do with the ideal gas law PV=nRT I'm sure you all remember.
OK, take an empy coke can or some type of aluminum can. Put just a teaspoon or so of water in it. Heat it up on a burner until the water is boiling (water vapor). Quickly take it off the burner and invert it into a shall ...[text shortened]... he temperature of the water vapor (approx. 100 C) and the temperature of the water bath.
🙂
I saw that demo online and it looked cool but the open flame made me uncomfortable.
Originally posted by mlpriorSome life doesn’t require oxygen to thrive (at least not free oxygen) e.g. anaerobic bacteria. The respiration of such life doesn’t rely on oxidation.
Would you consider respiration an example of oxidation?
What I'm getting at, is life itself a form of very slow oxidation?
Originally posted by Andrew HamiltonIt does. Since you need to gain energy from somewhere. But you don'tt need necessarily free oxygen to oxidise something. (That may sound a bit silly, but oxidation is not only the reaction with oxygen, but all chemical reactions in which electrons are transferred from one partenr to the other).
Some life doesn’t require oxygen to thrive (at least not free oxygen) e.g. anaerobic bacteria. The respiration of such life doesn’t rely on oxidation.
Originally posted by PonderableYes, I remember now, that is correct -I forget my chemistry courses 🙂
It does. Since you need to gain energy from somewhere. But you don'tt need necessarily free oxygen to oxidise something. (That may sound a bit silly, but oxidation is not only the reaction with oxygen, but all chemical reactions in which electrons are transferred from one partenr to the other).
Originally posted by AThousandYoungActually 8th graders. I forgot, I didn't do the demo for the 6th graders.
These kids aren't going to be calculating stuff with the Ideal Gas Law. That's high school I would imagine. These are 6th graders.
I saw that demo online and it looked cool but the open flame made me uncomfortable.