Brain&Force
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Unconventional lab experiments for high school
I want to prepare a good list of lab experiments that I can give to my school's teachers. These can't be just demonstrations - data must be obtainable
from them. Here are a few ideas I've come up with:
Build your own battery - A coin battery is built using pieces of metal and a piece of paper soaked in an oxidizer is inserted between them. Students
are given a choice of metals and their redox potentials are determined by measuring cell voltage with a multimeter.
Indicator identification - Similar indicators (such as methyl red, methyl orange, neutral red, methyl yellow, and thymol blue) are identified using
their transition points and appearances in buffer solutions.
Iodine clock timing - Iodine clock reactions are performed with varying concentrations of either peroxide, thiosulfate, iodide, and hydronium. The
timing of the reactions are measured and compared with the initial concentration to determine a rate law. At the end the students are given a random
interval and attempt to find the concentration that matches the given time. (This may also be possible with the chemical chameleon reactions.)
Feel free to add to or criticize my ideas.
[Edited on 1.3.2014 by Brain&Force]
At the end of the day, simulating atoms doesn't beat working with the real things...
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Fenir
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I have been attempting to do a chemistry project on the relationship between temperature and amount of caffine in coffee. The beans would be
contained in an improvised, filter paper, teabag. The caffine would be extracted via a liquid-liquid extraction and weighed after the solvent
evaporated.
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blogfast25
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Quote: Originally posted by Brain&Force  | Iodine clock timing - Iodine clock reactions are performed with varying concentrations of either peroxide, thiocyanate, iodide, and hydronium. The
timing of the reactions are measured and compared with the initial concentration to determine a rate law. At the end the students are given a random
interval and attempt to find the concentration that matches the given time. (This may also be possible with the chemical chameleon reactions.)
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Thiocyanate? Did you mean starch? Also, temperature as a parameter (T from 0 to 80 C) works well for quantitative runs with the iodine clock.
Simple electrolysis demonstrates many things at once: the constant atomic ratios of pure substances and also of course yield vs. t x I (Faraday).
NaHCO3 + acid to demonstrate endothermic reactions and what drives them.
Ca(OH)2 + K2CO3 === > KOH + CaCO3 as a useful displacement reaction that demonstrates solubility/insolubility.
Displacement of copper from solutions with Al/Zn/Mg.
Burning pieces of Mg ribbon of various length and weighing the oxide, to demonstrate that the ratio MgO/Mg is always the same.
pH indicators from colourful vegetables, always good for a few laughs....
[Edited on 28-2-2014 by blogfast25]
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Brain&Force
Hazard to Lanthanides
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Registered: 13-11-2013
Location: UW-Madison
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blogfast25: I meant thiosulfate or whatever reducer is used in the reaction. I didn't think about temperature though - that has a significant effect.
The electrolysis idea is killer! This would be interesting for diatomic elements.
Fenir: I don't think we have the apparatus for a liquid-liquid extraction. One interesting thing you can try is burning the coffee beans to measure
their energy content. Burn the bean over a measured amount of water with a thermometer immersed in it and calculate the temperature difference. The
energy can be calculated from the heat capacity of water and the mass of the water.
At the end of the day, simulating atoms doesn't beat working with the real things...
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zig
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Aluminum foil bits into drano (H2SO4), with a balloon rigged to catch the evolved hydrogen. Tie off the balloon, and detonate in a flashy fashion (ie
flicking burning match heads)!
What fun!
May have to be watered down since back then..
"The chemists are a strange class of mortals, impelled by an almost insane impulse to seek their pleasures amid smoke and vapor, soot and flame,
poisons and poverty; yet among all these evils I seem to live so sweetly that I may die if I were to change places with the Persian king."
-Johann Joachim Becher
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