# How to measure flow rate using Toricelli's law?

For my experiment, I want to investigate the relation between height and velocity using Torricelli's law. I would like to know how I would measure the flow rate from volume in a spouting cylinder.

• A calibrated orifice? – user207455 Jun 26 at 18:15
• What is a calibrated orifice? – Alireza ghasemi Jun 26 at 18:17
• Also is there any other simpler way of measuring flow rate. Since flow rate is volume per second, is there an instrument where I can measure the volume per 5 second. – Alireza ghasemi Jun 26 at 18:18

You can measure the velocity by measuring how far the water jet gets before it strikes the ground.

Suppose the jet takes a time $$t$$ to fall the vertical distance $$h$$ to the ground. This time $$t$$ will be given by the SUVAT equation:

$$h = \tfrac{1}{2}gt^2$$

So:

$$t = \sqrt{\frac{2h}{g}}$$

Then the horizontal distance travelled is:

$$s = vt = v\sqrt{\frac{2h}{g}}$$

And we simply rearrange this to get the outflow velocity $$v$$:

$$v = s\sqrt{\frac{g}{2h}}$$