PASCO Equal Length Spring Set

Purpose: The five color-coded equal-length springs in this set have different spring constants: 25 N/m, 30 N/m, 35 N/m, 40 N/m, 50 N/m (±5%) These springs appear to be the same except for their colors. But, when equal masses are hung on them, each stretches a different amount. What's Included: 1× White storage box 5× Five (color-coded) springs 30 cm long