Do springs really follow Hooke's law, f = –kx? Let's find out. We took three small "tension" springs (that is, you pull on them and they pull back, as opposed to a spring you would push on) from a hardware store and stretched them, measuring the force they pulled back with using a Vernier force probe.

length is the total length of the spring in centimeters.
force_N is the force it pulled back with in Newtons.
spring just designates which of the three springs we're looking at.

Do these springs follow Hooke's law? Over what range?

If you fit a line to the data, what do the slope and intercept mean?

What do the points mean where the force is zero?

(data by Bryan Cooley, Dec 2002)