manipulatives

Laser-Cutting CDs into Snowflakes

Dean Campbell | Wed, 03/08/2023 - 15:57

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Laser cutters can be used to cut and engrave a variety of thin materials. Compact discs, composed of layers of polycarbonate plastic and aluminum metal, were explored for their ability to be shaped with a laser cutter. The laser can successfully cut and engrave the compact discs into the shape of snowflake. However, each disc must first be coated with a material like glue in order to protect the plastic from discoloration and the byproducts from cutting the plastic that can accumulate on the disc surface.

Hatching Ideas to use Egg Cartons to Represent Electron Arrangements

Dean Campbell | Mon, 01/23/2023 - 14:11

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Egg cartons and small objects such as milk jug caps or plastic eggs can be used to illustrate chemical concepts. The egg cartons can be cut into trays to represent atoms or to represent energy levels associated with atomic orbitals. The plastic caps or eggs distributed among the dimples of the trays can be used to represent electrons or pairs of electrons.

A Demo A Day II: Demonstrations and Props Used in My Environmental Chemistry Class

Dean Campbell | Sat, 12/03/2022 - 21:08

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Short descriptions of demonstrations and props that Dean Campbell has used while teaching his collegiate Environmental Chemistry course. Many of these examples are also suitable for use in high school and collegiate General Chemistry courses.

Finding Flash Rocks

Dean Campbell | Sat, 08/13/2022 - 10:20

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Flash rocks were discussed in a previous post as stones made of quartz that produce light by triboluminescence when struck together. This post provides some description of their origins and tips on how to find them, making connections to some of their properties.

Flash Rocks from Green Chemistry and LEGO Brick Perspectives

Dean Campbell | Fri, 07/15/2022 - 23:56

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Flash rocks, typically pieces of quartz that produce light when struck together, are an example of the complex phenomenon of triboluminescence. The green chemistry aspects for the flash rock demonstration are considered, and LEGO models illustrating quartz crystals, piezoelectric materials, and nonpiezoelectric materials are presented.

Paper Snowflakes to Model Flat Symmetrical Molecules

Dean Campbell | Wed, 04/06/2022 - 13:39

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Flat, symmetrical molecules can be modeled by folding a sheet of paper, cutting patterns into the folded structure, and unfolding to produce the flat paper models. The finished models resemble paper snowflakes, but have a variety of rotational symmetries. Template patterns for several molecules are available for download in the Supporting Information.

A Demo A Day: Demonstrations and Props Used in My General Chemistry Class

Dean Campbell | Mon, 01/17/2022 - 17:43

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This blog post includes short descriptions of demonstrations and props that Dean Campbell has used while teaching his collegiate General Chemistry I course.

A Polystyrene Model of Polystyrene Tacticity

Dean Campbell | Sun, 11/21/2021 - 10:55

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Thin sheets of polystyrene can be patterned with permanent markers to represent repeating units of the polymer and then shrunk down in size using heat. The shrunken models of the repeating units can be connected with a string and then flipped into positions to demonstrate different types of polymer tacticity.

Microplastics, Liquid Nitrogen, and Iodine: Polystyrene vs. Starch Foam Packing Peanuts

Dean Campbell | Wed, 07/28/2021 - 13:03

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The differing electrostatic and solubility properties of starch and polystyrene foam packing peanuts are used in various demonstrations to describe aspects of microplastics and their interactions with the environment. Their differing responses to exposure to liquid nitrogen and iodine solutions are also described.

A Manipulative Paper Tool for Teaching Organic Nomenclature: Part 3- Common Names of Major Classes of Organic Compounds

Melanie Harvey | Tue, 06/15/2021 - 18:25

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This is the third in a series of classroom activities using paper tools to teach organic nomenclature. This post covers the two common naming systems used for carboxylic acids and derivatives, and second for alcohols, thiols, ethers, amines, and ketones.