Many educators across the country are teaching their students about π today in celebration of international π day tomorrow. We did too!

My goal for this lesson was not only to teach that π = 3.14159265359…, but what exactly is π?

BLE has loads of math manipulatives and project materials at our disposal. I laid out a bunch of these items in the room. Thea came to me knowing what diameter, radius, circumference, and area of a circle are. In fact, earlier in the week she made a plate illustrating diameter and radius and listing the formulas to calculate radius, circumference, and area.

I asked her to find five circular objects and find the diameter and circumference of each.

“What is the diameter?” Thea asked.

“I don’t know”, I replied, “How could we figure that out?”

She grabbed the ruler and made a measurement followed by digging out her plate so that she could calculate the circumference. I told her that she was not allowed to use the formulas on her plate. I received a puzzled look and then a smile.

“What is circumference?” I asked. She described and showed me that it is the distance around a circle. “Great. Without knowing the formula for circumference, how could you go about finding the circumference?”

“I could measure it,” Thea stated with a puzzled look “but the ruler is straight. That will make it too hard”.

“Are there other things you could use to make a measurement?” I inquired. Thea began looking around the room and came across a spool of string.

“I could use the string!” she exclaimed. She immediately began tracing the outer edge of her circular objects and measured the length of the string using a meter stick. When she was done I asked her to compare the circumference to the diameter by dividing one by the other (C/d). I called this the “Mystery Ratio”. Thea has not learned about ratios yet. I told her that a ratio is a comparison between two numbers and that the concept of ratios is a lesson for another day. 🙂

Exploring π

She noticed that her “Mystery Ratios” were very close to π leading us to a discussion about sources of error and how π is not just a number, but it is the circumference of a circle divided by its diameter.

One might ask “Why go through all this trouble when you could just tell the students what it is, which would take just a mere couple of minutes?” That is a fair question. This activity took us about an hour to complete. It spurred excitement, curiosity, and self-pride. Thea went home wondering how π  was discovered in the first place. I have also observed over the last 15 years that when providing students the opportunity for experiential learning they go home excited to share their discoveries with others and thus, making an imprint in their mind that will stick. This is the best self-assigned homework assignment I could ask for. Had I simply resorted to just spoon feeding the information to students, which I admit does happen, come this time next year they would probably forget the formula they were asked to memorize.

An added bonus to all this is truly enjoying being a part of helping the brain bulbs light up. This in turn inspires me to continue my work as an educator with gusto! I wake up in the morning excited to go to “work”.


– Brigitte Steinmetz (Owner/Education Director)