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Fluorescence Rocks! Exploring Glowing Sodalite

Dean Campbell | Wed, 08/21/2024 - 12:41

Syenite rocks containing sodalite that fluoresce yellow have been found on Lake Superior beaches in recent years and are of interest to collectors. The fluorescence of this mineral, which can be found in other localities, can be shown in classrooms and studied spectroscopically. Its structure can also be modeled with LEGO bricks, enabling further classroom connections.

Amount and rate of heat transfer using iron spheres and liquid nitrogen

Dean Campbell | Tue, 06/04/2024 - 11:00

When iron spheres at room temperature are added to liquid nitrogen, the nitrogen boils as heat is transferred in from the iron. The amount of liquid nitrogen boiled depends on the amount of heat transferred, which depends on the mass of the iron added. However, the rate at which liquid nitrogen boils depends on the surface area of the iron in contact with the liquid nitrogen. These phenomena can be studied with experiments which measure the mass lost by the boiling liquid nitrogen.

Demonstrating the Glass Transition of Polylactic Acid with a Rattle

Dean Campbell | Wed, 03/27/2024 - 20:42

Polylactic acid (PLA) exhibits a glass transition from hard and brittle to soft and rubbery when immersed in boiling water. PLA-based structures containing a small metal object can be used as rattles when they are shaken. The sound of the rattles change when they are heated above or cooled below their glass transition, enabling them to be used as demonstrations.