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Product 12529

By: Jonathan McClintock, St. Albert H.S., Council Bluffs, IA

In the Indirect Observations and Inference Demonstration Kit, students form a mental image of an object hidden under a blind and form hypotheses about its size, shape and composition while it is probed with a laser beam.

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Many of the experiments that led 20th century scientists to discover the nature of the atom involved indirect observation and inference. During the early 1900s, scientists like J. J. Thomson and Ernest Rutherford were faced with the challenge to develop an accurate mental picture of the atom—an object much too small to be directly observed. In this demonstration, students are asked to form a mental picture of an object hidden beneath a cardboard blind and formulate hypotheses about its size, shape and composition while watching you probe the object with a laser beam. Students are actively engaged throughout this demonstration exercise about indirect observation as they develop a deeper understanding of how scientists “knew without seeing.” Includes valuable Teacher Notes with helpful teaching teaching tips and reproducible student worksheets. All materials are reusable.

Concepts: Indirect measurement, atomic structure, inference.
Time required: 20 minutes
Materials Provided: Cardboard square, blotting paper, mirrors, laser pointer, 8-foot plastic band.