Build your own Birdhouse Kit, Teachers, this is a great and affordable way to get your kids Design, Building while creating something practical and at the same time beneficial for the environment, Perfect size for a chickadee or finch, Comes unpainted, Assembly required
Hand Held Centripetal Force Kit, Kit Includes: Plastic Handle, Rubber Stopper, String, 20 Washers, 2 Paper Clips, Provides The Necessary Tools To Discover Properties Of Rotational Dynamics. A Rubber Stopper Swings Around On The End Of A String Counter Balanced
Metal Blocks, For Density Determinations, Set Of Twelve In Assorted Sizes, Shapes And Masses. The Set Comprises Two Each Of Brass, Iron, Aluminium, Copper, Zinc And Lead. Masses Vary From 12 - 25 G