Page 46 - Demo

Flinn Lab Activities and Demonstrations
Atomic Structure—Demonstration Kits, continued
Indirect Observations and Inference—
Demonstration Kit
By: Jonathan McClintock
St. Albert High School, Council Bluffs, IA
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 such as 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. Every year many students faithfully study schematic diagrams of Rutherford’s “Gold Foil Experiment” without ever experiencing the thinking that led those scien- tists to their revolutionary conclusions. In this demonstration, students are asked to form a mental picture of an object hidden beneath a cardboard blind. Students must formulate hypotheses about the size, shape, and composition of the object 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 such as Rutherford “knew without seeing.”
Kit includes valuable Instructor’s Notes with helpful teaching tips, reproducible student worksheets and enough reusable materials to perform the demonstration an unlimited number of times.
Concepts: Indirect measurement, atomic structure, inference.
Time required: 20 minutes
Materials Provided: Cardboard square, blotting paper, mirrors, laser pointer, 8-foot plastic band.
Overhead Isotope Detector—
Demonstration Kit
By: Irwin Talesnik and John Eix, Retired
Queen’s University, Kingston, Ontario, Canada
Except for a very few elements, no atoms of any element have the atomic mass listed in the periodic table. This is due to the existence of isotopes. In this demonstration with an overhead projector steel spheres are magnet- ically separated by mass to simulate isotope separation. Based on the unique path of each sphere, students make calculations to determine mass ratios
of the sphere “isotopes” and the average atomic mass of the spheres. Concepts: Indirect measurement, atomic structure, inference.
Time Required: 20 minutes
Materials Provided: Picture frame and glass, neodymium magnets, launching ramp, glass marble, steel spheres, marking pen.
Paramagnetic Metal Ions—
Chemical Demonstration Kit
By: Jeff Bracken, Westerville North H.S., Westerville, OH
A great demonstration to introduce the difference between diamag- netic, paramagnetic and ferromagnetic substances. In this unique demonstration setup, four different metal salts are placed in chambers and suspended from dowel rods. A strong magnet is used to move the chambers and show the differences in the magnetic forces of the four salts. Demonstration Notes included.
Concepts: Magnetism, electron configuration, orbitals.
Time Required: 15 minutes
Materials Provided: Manganese(II) sulfate, copper(II) sulfate, zinc sulfate, calcium sulfate, salt chambers, dowel rods with hooks, neodym- ium magnet.
Note: A ring stand and two utility clamps are needed for this demon- stration but not included.
See free video at flinnsci.com.
1-800-452-1261
flinnsci.com
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Indirect Observations and Inference—Demonstration Kit AP7425
Catalog No.
Description
Price/Each
AP7425
Indirect Observations and Inference— Demonstration Kit
$50.70
Overhead Isotope Detector—Demonstration Kit AP7396
Catalog No.
Description
Price/Each
AP7396
Overhead Isotope Detector—Demonstration Kit
$40.75
Catalog No.
Description
Price/Each
AP6309
Paramagnetic Metal Ions—Chemical Demonstration Kit
$53.40
ATOMIC STRUCTURE—DEMONSTRATION KITS continued on next page.
Paramagnetic Metal Ions—Chemical Demonstration Kit AP6309