# Circumference: Popping Bubbles!!

Coming back to school after spring break is always a struggle, so obviously I thought playing with bubbles was a great way to start off the week. . I started off class by separating my students into greats of 3 and 4 and handing each group a container of bubbles. The only directions they were given were to start blowing bubbles.  The students were so excited that they could blow bubbles in school! After a few minutes, I asked them to come up with questions they could ask about bubbles. Students were asking all types of questions!

“How far will the bubble move?” “How big is the bubble?” “How fast does it move?”

“What’s the circumference?”  “What technique helps you create the biggest bubble?”

By students asking the questions, they become more invested in the activities in class.

Next, I poured a little bit of the bubble solution on aluminum foil a dipped a straw into the solution. At an angle, I blew into the straw  a half sphere bubble appear on the foil. I showed the students that when the bubble popped you could briefly see a circle in the foil.

I gave each group 1 straw, a large piece of tin foil, bubbles, string and ruler. Using ONLY those items, students had blow 7 bubbles and record the diameter and circumference of the bubble once it popped. They then needed to record their finding and then record the ratio of the  circumference over the diameter. The ratio should be close to Pi everytime!

My students already knew the formula for circumference but this activity really helped them visualize it and was a great, fun introduction to our circle unit! It was awesome watching groups cominig up with different ways to measure their bubbles.

This activity took around 25 minutes and then we spent the rest of the time practicing more complex circumference problems.