BRITS AND BEYOND: SCIENTIFIC REPORT: “HOOKE’S LAW”
Report by: Raúl López (2nd ESO E)
Lab colleagues: Guillén Aguado, Adrián Ferrer and Fernando Mur (2nd ESO E)
INTRODUCTION
A scientific law is “a statement that describes an observable occurrence in nature that appears to always be true”. That is to say, it refers to rules for how nature will behave under certain conditions. These rules will often be represented with an equation (a formula).
Today we are testing Hooke´s Law, which states that: “The force (F) needed to extend or compress an elastic body by some distance (ΔL) scales linearly with respect to that distance”. In other words, force applied and deformation produced are directly proportional (as long as we don’t exceed the elastic limit, in which case the body would be permanently deformed).
Let’s see if Hooke was telling the truth.
USED MATERIALS
For this experiment, we used:
- Two springs: each one should give us a different value for the elastic constant.
- A dynamometer: to measure the force
- Some dumbbells that we will hang on the springs to test the deformation
- A holder to hold the dumbbells
- A measuring tape to measure the lengths of the springs
PROCEDURE
First, we measure the spring to know its initial length. Then, with the dynamometer, we measure the force that the dumbbells make. After that we apply that same force to the spring and measure its final length. Subtracting the final minus the initial length, we have the elongation produced.
We repeat the process for times with different combinations of dumbbells and with two different springs to have more accurate results, because as humans we can make mistakes when measuring, and because sometimes instruments are not very precise, so it is better to have more than one measurement.
CONCLUSION
On the one hand, for each of the springs, the value of the elastic constant is more or less the same. This confirms the accuracy of Hooke’s Law.
On the other hand, each spring has a different value for the elastic constant, which is also consistent with what we wrote in the introduction.
- Spring 1: it needs 4,3 N to be stretched 1 m
- Spring 2: it needs 16,6 N to be stretched 1 m
So, we can conclude that spring 2 is harder than spring 1 (we need more force to have the same elongation) and that Hooke was right when he enunciated his law.
We learned that it is important to work in an ordered way so we don’t get confused with all the data that we recorded, and that the accuracy in the measurements is something that must guide our job as scientists.
