density

Chemistry in a Bottle

Tom Kuntzleman | Fri, 05/05/2017 - 07:06

Are you familiar with the dynamic density bottle experiment? This interesting experiment was invented by Lynn Higgins, and is sold by various science supply companies. Two immiscible liquids (usually salt water and isopropyl alcohol) and two different types of plastic pieces are contained within a dynamic density bottle. The plastic pieces display curious floating and sinking behavior when the bottle is shaken.

Unit Conversions: The good, the bad and the ugly

Lauren Stewart | Wed, 08/31/2016 - 18:19

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Like most chemistry teachers, one of the first things I go over in the beginning of the year is unit conversions. Students come into my class with all sorts of prior knowledge concerning unit conversions; some good, some bad and some downright ugly.

Chemical Mystery #7: Curious Cans

Tom Kuntzleman | Wed, 07/06/2016 - 14:11

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Q: Does an unopened can of soda pop float or sink in water?

A: It depends!

See if you can figure out what is happening in this twist on the classic floating-and-sinking soda can experiment.

An Unexpected Source of Inquiry-Based Lab Practicals

Erica Posthuma | Sat, 03/19/2016 - 16:54

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Each spring my Local Section of The American Chemical Society (ACS) hosts a rigorous two part exam as part of the selection process for the The International Chemistry Olympiad (IChO). The lab practicals on the exams are presented as problems. No procedure is given. Students must use their chemistry knowledge and lab experience to devise a plan and solve the problem. The best part is that the released exams come with lists of materials and equipment, helpful hints to the proctors, and solutions! This is a great source for Inquiry-Based Lab Practicals.

Rainbows in a Glass Density Demonstration

Tom Kuntzleman | Sun, 06/22/2014 - 11:34

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One day during class I presented the disappearing rainbow demonstration and explained the chemistry behind it. After doing so, I had a student ask me if a particular bartending trick called “rainbow shots” was done in a manner similar to the way the disappearing rainbow demonstration is performed.