Low RPM Toy Motors for Physics Lab - Ideas Needed

[JFS321]

All, I teach physics and would like do a hands-on lab where students are using motors to investigate the concepts of angular velocity and RPM. I've searched Amazon and eBay for low RPM toy motors, preferably those that could be easily powered with a couple of 1.5V batteries. Not much luck.

Any ideas on what I could use to sustain a relatively low RPM (so students could count frequencies)?

Many thanks.

 

[kuruman]

What's your budget? Amazon will sell you a $16.95 solar-powered toy fan. Presumably you can control the speed by controlling the incident light on the solar cell.

 

[JFS321]

Good idea, and I may end up using it. I was originally hoping for toy motors because they are cheap, and I could purchase enough for about 8 groups. I'm spending my own money so I'd like to keep it $20-30 if at all possible.

 

[JFS321]

I did find these on Amazon, and I could power them with 4 AA batteries in series (another good lesson for students to figure out).

https://www.amazon.com/dp/B009AQLDSS/?tag=pfamazon01-20

To make things easier, I do have 9 V battery connectors. Other than increasing RPM, would there be any issue with using 9 V instead of 6V?

 

[kuruman]

If you read the questions, someone claims to have hooked up a 9 V battery and "it seemed to handle it well". Another good lesson might be to hook up a voltage divider to the 9 V battery.