PacSci Perspectives

Paws-On Science + CO2 = Cool Third-Grade Science Project

by | Jun 30, 2016

With about a week until her school science fair, nine-year-old Penelope was stumped. She wracked her brain, but couldn’t think of a good project to enter in the science fair. Then, she and her mom attended Paws-On Science: Husky Weekend, an annual event featuring three days of interactive activities highlighting cutting-edge research at University of Washington. There were beading activities that illustrated gene sequencing, demos about “elephant toothpaste”, a hands-on game to hunt viruses, a build-a-buoy challenge using PVC pipes and lots more!

“Would you like to learn about ocean acidification?” a smiling scientist from University of Washington asked the third grader.

“I had no idea what ocean acidification was, but it’s fun to learn about things you don’t know about,” Penelope said. Already a nature enthusiast, Penelope was eager to learn about the ocean.

The hands-on experiment was simple, but spectacular. Participants blew through a drinking straw into a cup filled with distilled water, sodium hydroxide and three drops of bromothymol blue (a pH indicator). After about 10 seconds of blowing, the liquid dramatically changes color, from blue to yellow.

UW researchers explained: when people exhale, their breath contains carbon dioxide (CO2). While CO2 is not acidic by itself, when combined with water it creates a weak acid. Of course, the CO2 we’re breathing out is part of a natural cycle, so our breath does not add any extra CO2. In contrast, fossil fuel combustion releases CO2 that has been locked up for millions of years, producing a net contribution to planetary CO2 levels.

Penelope was blown away. “Just like when wind mixes carbon dioxide from the air into the ocean, the experiment shows how C02 can make the water so acidic that it dissolves limestone and sea shells.” The UW demonstration spurred her to enter her school’s science fair.

Penelope put together a poster explaining fossil fuels and the effect of CO2 on the ocean. Her mom contacted Professor David Sommerfeld, a senior lecturer at University of Washington, Bothell, who gladly shared his recipe for the drinking-straw experiment along with some leftover ingredients. To further illustrate the dramatic effects of acid on sea life, Penelope soaked a seashell in vinegar; by the next day, part of it had completely dissolved. Her science fair project was a hit. “All the teachers liked it a lot and asked a lot of questions which made it challenging, but it was more fun because it wasn’t easy.”

The hardest question: “How can we stop it?”

Penelope’s answer: “It seems like we could really do something if more people were educated about this issue. They could become more mindful about what they’re putting into the air and the ocean when they are driving their cars and be inspired to ride bikes and walk to school more often.”

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