July 23, 2008

How the Mentos Geyser Works - Theory Confirmed!

It's probably the most asked question we get... "How exactly does that experiment with the Mentos and Diet Coke really work?" From the outset (nearly eight years ago), we hypothesized that the exploding soda was a physical reaction, and the key factor in the release of carbon dioxide was the microscopic pits on the surface

of the chewy mint. However, there was no real scientific study that anyone could point to as the definitive answer... until now. In the June issue of the American Journal of Physics, Tonya S. Coffey, an assistant professor of physics and astronomy at Appalachian State University, in Boone, N.C., and her team of fearless physics students reported on the ingredients, temperature dependence, duration, and other parameters of the suddenly famous Mentos-Diet Coke reaction.

There has been considerable debate over gum arabic (found in the coating of the mint) and the role it plays in the physical reaction. Coffey’s group was able to confirm that the surfactant gum arabic is a key component of the reaction: It reduces surface tension, thereby

… (more...)

June 26, 2008

UV Beads Help Students Understand the Importance of Sunscreen

You might have seen t-shirts or special jewelry (beads) that changes color in sunlight. UV Beads look like ordinary white beads used to make a craft project, but embedded in the plastic is a special pigment that changes color when exposed to ultraviolet light. The color change takes place in just seconds - almost like magic. Mrs. Bratteli’s Third Grade Class from Aikin Elementary School in Paris, Texas, used the beads as a way to see if sunscreen lotion really blocks out harmful ultraviolet light from the sun. We did an experiment with your UV beads and sunscreen and the types were 10, 30, and 50 SPF. We put them each on a foam plate and had a nothing plate. [control—no sunscreen] They changed colors exactly how they were supposed to, but the 50 you couldn’t see. Read the full experiment write-up. But, like all good experiments, these third graders discovered something else... We left them all over the weekend and here are our results. The SPF 50 sunscreen also ate through the Styrofoam plate! The spf 10 … (more...)

June 24, 2008

Mentos Geyser Records Keep Exploding

So, America throws it back to the Europeans... from Louisville, KY to Turiba University in Latvia there is a new Mentos and Diet Coke World record. On June 19th, 1,911 students from Business University Turiba in Latvia launched an amazing geyser eruption and landed themselves in the Guinness Book of World Records, just over a month after students at Male High School in Kentucky launched 1,800 simultaneous geysers to earn their own world record status. The Latvian University students were celebrating the school's 15th anniversary, and what better way to celebrate than with Mentos and Diet Coke. Check out the video of this monumental occasion. Now, who's next...

June 23, 2008

Experiment of the Week Travels to Germany

It’s great to get your e-mails and photos of your children and students doing the science activities featured in our Experiment of the Week. These photos are from Sheila Allen, just one of a number of great teachers in the Department of Defense Schools at Ramstein AFB in Germany. Sheila writes... “Well today was the big day and boy did the children have fun! I think my favorite was the Expanding Ivory Soap activity, and I picked just the right kid to trick with the Do Not Open Bottle. We were doing an A-Z countdown to the end of school and so for E we did experiments, and we thought your activities really hit the high point for us! There are 9 kindergarten classes at Ramstein Elementary school (K-2) , and it is a good place for science to happen.” Sheila Allen and her team of mad scientists are a great example of how early childhood teachers are having an incredible impact on the science concepts that young children are being exposed to in the early years of their education. Over the last 15 years, I’ve seen countless examples … (more...)

June 20, 2008

Kentucky Students Set New MENTOS Geyser Record

Not to be out-done by Europeans, students at Male High School in Louisville, KY, set off 300 more geysers than the previous record-breaking effort just a few months ago in Belgium. School officials thought exploding Diet Coke and MENTOS would be a great way for students to blow off a little steam before finals and celebrate a great school year. The students were recognized by the Guinness Book of World Records as the new official record holders with 1800 geysers. All proceeds from the event were donated to the Ronald McDonald House. Congrats to Male High School students... now who will be next in the race for a new geyser world record?