Frind relationship between angular velocity and angle of a conical pendulum

In the lab, our purpose is finding the relationship between the angle of conical pendulum and angular velocity.And this is the picture showing about lab:

And then, we use the ruler to measure l ans L.
l: 0.6 m L: 0.67 m H(total height) : 2.3 m
However, what should we do for measure the angular velocity? And what can we measure the angle during the object is rotating? We will get not accurate number if we only use angle measure tool and angular velocity measure tool. Thus,we can use equation to instead it to  measure the angle and angular velocity.

Angular velocity = 2*Pi/period

Thus, after measuring data, we got those number:

1. T1=3.968s h1=0.5m
2. T2=3.288s h2=0.628m
3. T3=2.953s h3=0.762m
4. T4=2.698s h4=0.955m
5. T5=2.514s h5=1.066m
6. T6=2.205s h6=1.14m
7. T7=1.99s  h7=1.425m
8. T8=1.85s  h8=1.487m

From those number, we use equations to get the graph:

Now, the goal of this lab is finding the relationship, so we made some equations:

divide both side with m:

Because the r is changing with the angle, so we wrote the equation between r and angle:

we apply those two equations, and we can got:

So we use Excel to get the angular velocity by the angle:

From this graph, we can figure out that theory w and real w are similar, so the equation about angle and angular velocity is correct.