Friday Bubbles

This activity is a lot of fun for 6th graders to discover for themselves the relationship between diameter and circumference.

Given a small container of bubble solution, the student pours a little of it onto his/her desk and use a straw to blow a bubble. When a bubble pops, it leaves enough of an imprint on the desk for the student to measure its diameter and circumference with a string. Students continue to blow different-sized bubbles and record their measurements.

Mix these three ingredients together well for a perfect bubble solution. I doubled this recipe to make enough for 34 students working in pairs.

  • 1 cup distilled water
  • 2 tbsp Karo light corn syrup
  • 4 tbsp Dawn dishwashing liquid


I put the bubble solution in small plastic cups. Paper cups do not work! I give students embroidery threads to use as “string” to measure diameter and circumference. Of course they then have to measure the string against a ruler to get a reading in centimeters.

They work in pairs — one person blows a bubble and measures, the other person records; they wipe off desk, string, and ruler after each bubble. Switch roles. I ask for at least five different-sized bubbles.


Not wanting to waste the leftover bubble solution, I let the kids go outside to blow bubbles in the Friday afternoon sun. One kid said, “Today is such a good day.” Other kids quickly chimed in to agree.


I really think they will remember that the circumference is about three times the diameter. Yeah, that 3.14159 pi thingy.

This entry was posted in Course 1 (6th Grade Math) and tagged , , , , , , . Bookmark the permalink. Post a comment or leave a trackback: Trackback URL.

One Trackback

  • By Math Teachers at Play #76 | Let's Play Math! on July 23, 2014 at 2:35 am

    […] Fawn Nguyen’s students have fun investigating the relationship between a circle’s diameter and circumference in Friday Bubbles. […]

Post a Comment

Your email is never published nor shared. Required fields are marked *

You may use these HTML tags and attributes <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>