A student in Australia says math teacher Rob Tarrou is "smart, humble and helpful." • A student in Sweden tells him "you help more people than you ever imagine." • A student in India writes: "u r an absolute genius!!! Hats-off!"
Tarrou has been at St. Petersburg High School for 17 years, and says he loves teaching students algebra, trigonometry and statistics, even more than he loves algebra, trigonometry and statistics.
Last year, he landed on an additional way to teach — through YouTube. He has posted more than 300 videos on such topics as factoring, right angle trigonometry, standard deviation and — this one had more than 33,000 views — "z-score Calculations & Percentiles in a Normal Distribution."
Tarrou, 41, began posting his self-made videos in the fall of 2011, partly to help a student who couldn't attend class.
Now, people around the world have watched "Tarrou's Chalk Talk" videos more than half a million times. More than 3,000 people from more than 100 countries have subscribed to his online channel.
"I had a pen pal in Iceland for statistics," he said.
Another fan lives in Brazil. "From Brazil! That's freaking awesome," he said.
Online education is not new to Florida public schools — thousands of students get high school credit through the Florida Virtual School. But combining online educational videos with traditional classroom instruction is a hot topic in education circles.
Some educators talk about the "flipped classroom," said Gladis Kersaint, a professor of math education at the University of South Florida. Students learn the basic concepts of a subject through online lectures, reserving classroom time for working through higher-level problems or asking questions directly to the teacher.
She said online educational videos can help students, but as with any information on the Internet, it pays to be a careful consumer.
"I think the user would have to learn something about the creator,'' Kersaint said. "Do they have the credentials to be doing this?"
At St. Petersburg High, Tarrou still teaches pretty much as he always has, but the videos give his students added help. In addition to reading their own notes on skills such as graphing lines in slope-intercept form, students can go to his YouTube video on the same topic for reinforcement.
Some of his local students say it's helpful that YouTube comes with a pause button, unlike a classroom lecture. So they can replay a difficult concept over and over.
"It's almost like having one-on-one tutoring," said Justin Downey, 18, a senior in Tarrou's advanced placement statistics class. Compared to some other online resources, he said, "the quality's a lot higher."
A reporter recently asked students in that statistics class how many had other teachers post educational videos online. No one raised a hand. Next, students were asked how many wished their other teachers would post videos online. Nearly all raised their hands.
"I think it's a good thing, and I think it's probably the future," said Al Bennett, St. Petersburg High principal.
While the videos are useful for Tarrou's classroom students, their appeal spans the globe.
"My cousin in Croatia actually watches the videos," said Martin Grabovac, 16, a junior at St. Petersburg High.
A fan in British Columbia posted on Tarrou's Facebook page: "wow I'm paying 800 dollars to be taught pre calculus at school, and i must say i have learned SO much more with watching your videos than sitting in class listening to my teacher.''
Tarrou started out shooting his videos in a classroom, but now he takes steps to make sure his schoolteacher job and his YouTube hobby stay separate. He now has a chalkboard at his house, which is where he shoots all his videos now with help from his wife, Cheryl. And the hobby is becoming a side business, because YouTube sells ads connected to his videos. He declined to get into specifics, but did say he has earned more than $100 each month since March.
As a classroom teacher and as a video instructor, Tarrou has a slightly quirky style that seems to engage students. He likes to wear goofy T-shirts that say things such as "Let me drop everything and work on your problem." Which might sound sarcastic, but Tarrou is completely sincere.
But he's not always serious.
One day in class recently, he said in a matter-of-fact tone, "I put all kinds of stuff on the (upcoming) test that I've never taught you."
Students' eyes got very big, very fast. "What?" several of them said.
Tarrou smiled, to let them know they'd been punked.
In the middle of class, he might say things like, "Aaron, you can ask me a question, I'll only laugh at you a little bit."
Sincere or silly, his students like him.
Several in the statistics class said they wouldn't have dreamed of taking AP math class without Tarrou.
"I don't like math," said Melissa Kent, 17, a senior. "But it's my favorite class because of Mr. Tarrou."
Curtis Krueger can be reached at firstname.lastname@example.org.