Colored Threads, w.m., for teaching students to focus the microscope; a red thread lies across a blue thread, which in turn is across a yellow thread.
Oakley STEM Center Lending Library
https://www.tntech.edu/stem
155 W 7th Sthttps://www.tntech.edu/stem
Cookeville, 38505
USA
(931) 372-6573