Guinea and Feather Apparatus, 20" Glass Tube Gifts_Bar Acrylic bell-in-vacuum jar with an

Acrylic bell-in-vacuum jar with an internal 4-6V DC electric bell that fades and falls silent as the enclosed air is removed

supporting dental hygiene and pathology teaching

Ninety-five-piece molecular model set with 53 atoms and 42 links spanning organic and inorganic chemistry

anchoring side-by-side magnet-strength comparisons for the classroom

controllable flame shape during laboratory heating

Guinea and Feather Apparatus, 20" Glass Tube Gifts_Bar Acrylic bell-in-vacuum jar with anDrops a dense object and a feather together inside a 20 inch evacuated glass tube, showing that air resistance not mass accounts for differences in fall time under gravity.