In this Activity, students observe UV-sensitive beads that have been melted into flat disks, explore the temperature behavior of the disks, and then use the disks to investigate the effectiveness of different sunscreens. The Activity shows applications of chemistry in the real world.
Atomic Properties / Structure
In this Activity, students compare incandescent bulbs and LEDs powered by dc and ac voltage sources. They use circuits made from cut-up holiday light strands, with some of the incandescent bulbs replaced with LEDs. The diode nature of LEDs is demonstrated, as well as the energy associated with different wavelengths of light.
In this Activity, students investigate the magnetic interactions between a flexible-sheet refrigerator magnet and a probe tip cut from the same magnet to deduce the relative arrangement of the magnetic poles. These interactions are used as a macroscopic analog of scanning probe microscopies. The Activity could be used when atoms are introduced.
In this Activity, students test common household substances to see how they change the way paper burns. Strips of filter paper are soaked in saturated solutions, dried, and briefly held in a flame. The Activity demonstrates the effectiveness of flame retardants. It could be used when discussing combustion reactions or during a unit on practical or everyday chemistry.
In this Activity, students investigate static electricity. They observe that charged objects attract a narrow stream of water, and find that charged combs and glass rods have opposite charges. This Activity could be used to introduce the notion of positive and negative electric charge. It is appropriate when studying atomic theory, and when introducing electrochemistry.