There's a very interesting way to find the angular velocity of a wheel that's spinning so fast that you can't measure using a stopclock. We'll be using a strobe light (a light that flashes on and off repeatedly) and a very interesting concept known as the Wagon Wheel effect under stroboscopic conditions.

##A little bit about the concept:

The Wagon Wheel effect is a phenomenon in which a spinning wheel may appear to be stationary under a strobe light. The reason why this happens is quite simple, the rotational frequency of the spinning wheel is an integral multiple of the the strobe light's on-and-off frequency. As a result, every time the strobe light flashes, the wheel comes to the same position as before. This creates the illusion that the wheel was stationary.

But how will we use this concept to find the rpm of a spinning wheel? Let's find out.

##The experiment:

You'll only need a strobe light (you can download strobe light apps for Android and probably for iOS as well) and your spinning wheel. In this answer, I'll be using a fidget spinner to demonstrate.

Keep the room as dark as possible, and set your wheel to motion. Turn on the strobe light and start with a high flash frequency and gradually lower the frequency until you see the wheel become stationary. We do this because don't want other integral multiples of the frequency to match up with the spinning wheel.

Take a note of the strobe light frequency $\nu$. In my case, the fidget spinner appears stationary at a frequency of 13.3 Hz. As we mentioned before, the wheel appears stationary only when the frequencies match. So, the frequency of the strobe light is the rotational frequency of the wheel. So, I can say that my fidget spinner makes 13.3 revolutions per second. And of course, it's rpm would be 798.

I hope you enjoyed this fun experiment. If you have any queries, please drop them at the comments. If you have a better way to find the angular velocity, don't hesitate to write an answer.

There's a very interesting way to find the angular velocity of a wheel that's spinning so fast that you can't measure using a stopclock. We'll be using a strobe light (a light that flashes on and off repeatedly) and a very interesting concept known as the Wagon Wheel effect under stroboscopic conditions.

A little bit about the concept:

The Wagon Wheel effect is a phenomenon in which a spinning wheel may appear to be stationary under a strobe light. The reason why this happens is quite simple, the rotational frequency of the spinning wheel is an integral multiple of the the strobe light's on-and-off frequency. As a result, every time the strobe light flashes, the wheel comes to the same position as before. This creates the illusion that the wheel was stationary.

But how will we use this concept to find the rpm of a spinning wheel? Let's find out.

The experiment:

You'll only need a strobe light (you can download strobe light apps for Android and probably for iOS as well) and your spinning wheel. In this answer, I'll be using a fidget spinner to demonstrate.

Keep the room as dark as possible, and set your wheel to motion. Turn on the strobe light and start with a high flash frequency and gradually lower the frequency until you see the wheel become stationary. We do this because don't want other integral multiples of the frequency to match up with the spinning wheel.

Take a note of the strobe light frequency $\nu$. In my case, the fidget spinner appears stationary at a frequency of 13.3 Hz. As we mentioned before, the wheel appears stationary only when the frequencies match. So, the frequency of the strobe light is the rotational frequency of the wheel. So, I can say that my fidget spinner makes 13.3 revolutions per second. And of course, it's rpm would be 798.

I hope you enjoyed this fun experiment. If you have any queries, please drop them at the comments. If you have a better way to find the angular velocity, don't hesitate to write an answer.

There's a very interesting way to find the angular velocity of a wheel that's spinning so fast that you can't measure using a stopclock. We'll be using a strobe light (a light that flashes on and off repeatedly) and a very interesting concept known as the Wagon Wheel effect under stroboscopic conditions.

##A little bit about the concept:

The Wagon Wheel effect is a phenomenon in which a spinning wheel may appear to be stationary under a strobe light. The reason why this happens is quite simple, the rotational frequency of the spinning wheel is an integral multiple of the the strobe light's on-and-off frequency. As a result, every time the strobe light flashes, the wheel comes to the same position as before. This creates the illusion that the wheel was stationary.

But how will we use this concept to find the rpm of a spinning wheel? Let's find out.

##The experiment:

You'll only need a strobe light (you can download strobe light apps for Android and probably for iOS as well) and your spinning wheel. In this answer, I'll be using a fidget spinner to demonstrate.

Keep the room as dark as possible, and set your wheel to motion. Turn on the strobe light and start with a low flash frequency and gradually increase the frequency until you see the wheel become stationary. We do this because don't want other integral multiples of the frequency to match up with the spinning wheel.

Take a note of the strobe light frequency $\nu$. In my case, the fidget spinner appears stationary at a frequency of 13.3 Hz. As we mentioned before, the wheel appears stationary only when the frequencies match. So, the frequency of the strobe light is the rotational frequency of the wheel. So, I can say that my fidget spinner makes 13.3 revolutions per second. And of course, it's rpm would be 798.

I hope you enjoyed this fun experiment. If you have any queries, please drop them at the comments. If you have a better way to find the angular velocity, don't hesitate to write an answer.

There's a very interesting way to find the angular velocity of a wheel that's spinning so fast that you can't measure using a stopclock. We'll be using a strobe light (a light that flashes on and off repeatedly) and a very interesting concept known as the Wagon Wheel effect under stroboscopic conditions.

##A little bit about the concept:

The Wagon Wheel effect is a phenomenon in which a spinning wheel may appear to be stationary under a strobe light. The reason why this happens is quite simple, the rotational frequency of the spinning wheel is an integral multiple of the the strobe light's on-and-off frequency. As a result, every time the strobe light flashes, the wheel comes to the same position as before. This creates the illusion that the wheel was stationary.

But how will we use this concept to find the rpm of a spinning wheel? Let's find out.

##The experiment:

You'll only need a strobe light (you can download strobe light apps for Android and probably for iOS as well) and your spinning wheel. In this answer, I'll be using a fidget spinner to demonstrate.

Keep the room as dark as possible, and set your wheel to motion. Turn on the strobe light and start with a high flash frequency and gradually lower the frequency until you see the wheel become stationary. We do this because don't want other integral multiples of the frequency to match up with the spinning wheel.

Take a note of the strobe light frequency $\nu$. In my case, the fidget spinner appears stationary at a frequency of 13.3 Hz. As we mentioned before, the wheel appears stationary only when the frequencies match. So, the frequency of the strobe light is the rotational frequency of the wheel. So, I can say that my fidget spinner makes 13.3 revolutions per second. And of course, it's rpm would be 798.

I hope you enjoyed this fun experiment. If you have any queries, please drop them at the comments. If you have a better way to find the angular velocity, don't hesitate to write an answer.