Magnetic Inclination Needle for Earth Field Demonstration Biology_Entomology & Zoology and triple-parallel plastic wheels at

and triple-parallel plastic wheels at 50mm diameter in low-friction ball-bearing steel frames

Thirty-atom organic chemistry model set with 24 short and long bonds

temperature-stable cylindrical magnets are needed

producing the nearly uniform field used to calibrate magnetic sensors and verify the Helmholtz geometry

and vascular cylinder for plant anatomy and absorption teaching

Magnetic Inclination Needle for Earth Field Demonstration Biology_Entomology & Zoology and triple-parallel plastic wheels atVertically pivoting magnetic needle that visualizes the dip angle of Earth's field, showing how inclination shifts from horizontal at the equator to vertical at the poles.