We have measured the strength “k” of a mechanical spring using both static and dynamic methods. In the static method, we explored Hooke’s Law, F(x) = -kx, by recording stretch length for various masses hung on a spring and obtained ks = 1.45 ± 0.05 N/m. In the dynamic method, we measured oscillation period for the same set-up and obtained kd =1.51 ± 0.03 N/m. These two methods agree within their uncertainty, but the dynamic method is more precise. The static method revealed a built-in tension, such that the “rest length” L0 ~ 10cm was less than the physical length Lm=12cm for no mass. The dynamic method revealed that the mass of the spring itself contributes an effective mass of m0= 110 ± 20 g.