Monday, September 9, 2013

Thinking Like a Scientist - Diet Coke and Mentos

During the first week of school, our third grade students talked about what it means to be a scientist.  We brainstormed and came up with ideas of what a scientist does.  These included saving the environment, building technology, and discovering things.  After we made this list, we drew and colored what the students thought a scientist looked like.  Nearly every kid drew a scientist with gloves, a lab coat, and goggles.

The lessons culminated with a lesson on how a scientist discovers things.  I taught them that a scientist begins by asking a question, sometimes even lots of questions.  After coming up with the question, the scientist develops a hypothesis, what he thinks will happen.  Next, he conducts his experiment and records his data.  Finally, he analyzes the data and comes up with his conclusion and determines if his hypothesis was right or wrong.

The big event for the week was the Diet Coke and Mentos experiment. Many of our families were gracious enough to donate the needed materials. We chose Diet Coke, diet lemon lime soda, and diet root beer. We also used mint-flavored Mentos. Here are some of the results:

Needless to say, the students had a blast participating in the activity, even though I was the one having all the fun. This is a really easy and exciting activity to do and only needs a few materials. There is a website devoted to the science behind this experiment with a lot more videos. The website is called

Many of the students were asking me about the special tube I used in the experiment. I used a special tube that attached to the top of the soda bottle and allowed me to load the Mentos into the bottle and pull a string after moving safely away. That tube is called Steve Spangler's Geyser Tube. The Geyser Tube not only kept me dry, it also controlled the flow of the "eruption" from the soda, allowing it to go much higher. The Geyser Tube can be purchased at, but I have also seen them at Cracker Barrel and sometimes at toy stores in the mall.

It was a great first week teaching science and I am looking forward to the exciting things we have planned for teaching matter.

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