Bifilar Pendulum: Need help with formulas now... 1. The problem statement, all variables and given/known data So I have an assignment where I have to determine the relationships between the period of a Bifilar Pendulum. I performed an experiment where the angle was set to 20 degrees, the ruler tied to the strings is twisted, and then it is let go and after 3 periods, the timer is stopped. The independent variables are the length of the strings and the distance between the strings. The above photo should help you understand what a bifilar pendulum looks like. The experiment my group performed was very similar to the set up shown in the picture. We also had to create a hypothesis, justify it and then justify the results. I would really like to do well for this assignment, but the problem is I can't create a good hypothesis because the information on the internet seems limited. The reason I didn't create a hypothesis before the actual experiment is because there wasn't enough theory found to create one. 2. Relevant equations This is what I am trying to find. Justifying the hypothesis is really as easy as saying "an expert on the matter said this would happen." So what if he was wrong/the experiment says he is wrong? At least I have my experiment results to compare it to, and see whether similar results were obtained, and then I can restate a hypothesis. However, I would like it if someone could help me link my hypothesis to physics theories (so why is the period proportional to the inverse of the length?) so I can do the best I can. 3. The attempt at a solution So far I have my results, and found the relationships between the period with my independent variables. T=k x 1/d where T is period, k is the constant and d is the distance between the strings. In addition, T=o x √l where o is the second constant and l is the length of the strings vertically. However, when one of the 2 constants is found (because the constants are different for each variable), they are used again in the same formula with the same variables, and the answer comes out wrong. Is this because of human error? I'm fairly sure the constant is equal to the gradient of a graph where the two variables (time and 1/d) are plotted. Is this correct? So to wrap it all up, can someone help me create a justifiable hypothesis (that is not based on my results obviously) and help me analyze me results? You would help me a lot!