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Plop! Plop! Fizz, Fizz in the Lab!

Do you remember the television commercials for Alka-Seltzer- “Plop, Plop, Fizz, Fizz, oh what a relief it is!”

So, there’s a story behind this one!

I was looking for something in one of our lab cabinets and a box of effervescing tablets fell out. A third grader saw the box and said,

“Hey, my grandma has these!”

Well, that was heartbreaking- this is a stomach medicine we use at my house! Am I old enough to be a grandma? #yes

Then I had to explain why I had a box in the lab and it involves rockets and it is not an event I do with third graders, but it made me start thinking…. BAM! Brain pop time. (Plus I needed something for one class to do while we waited for the other classes to catch up!)

Plop Plop Fizz Fizz Effervescing Experiments- students experiment with several liquids and then design their own experiment.

So, here’s a little more background….

My third graders need some help with understanding the Scientific Method.

When you start talking about variables -controlled, dependent, and independent – it gets very confusing. And with eight-year-olds it is really interesting to get them to understand controlled variables and how to make the experiments fair.  

So, I have two really cool experiment activities that help us learn about variables in a fun way.

Which brings us back to ‘plop, plop, fizz, fizz’ effervescing tablets. Just saying those two words is pretty cool!

Plop Plop Fizz Fizz Effervescing Experiments- students experiment with several liquids. Your prep includes making trays of the tablets and cups.

“Oh, boy, we are doing real science today!

I prepare these trays ahead of class time. The effervescing tablets are the generic brand from Wal-Mart and I cut them into fourths.

The little cups either come from Wal-Mart of Amazon. You can use 3-ounce cups too. I prefer the clear cups so you can see the fizzing!

We use these graduated cups all the time. They are plastic and we just rinse them out when we finish an activity.

TIP: To cut the effervescing tablets into fourths I use a steak knife. I score the tablet across the center in two directions and then snap the tablets apart.

Effervescing Experiments and Design- students experiment with different liquids. They begin with a hypothesis!

Can you say Effervescing correctly?

For this Scientific Method exploration, we first had to learn the word Effervescing. It means a bubbling effect due to a chemical reaction and the result is dissolving. Think Alka Seltzer and you will totally get it!  

The question for this experiment was, “What will make the effervescing tablet dissolve faster?”   The student in the photo above wrote, 

“I predict saliva or some sort of acid will make it faster.”

Nope, sorry we will not be using saliva.

Effervescing Experiments and Design- students experiment with different liquids. They record the results of each step of the experiment.

What is going to happen?

After forming a hypothesis we set about to test the effervescing tablets. This was a very planned procedure with everyone doing it at the SAME TIME because these are third graders and they could not be turned loose with fizzing and bubbling and watching the clock at the same time.

We timed each tablet dissolving rate by using a very large stopwatch from a website I found. I have stopwatches the kids can use, but with this age group, it takes too long to get everyone to use them correctly and push the right buttons!   The kids recorded their results.

Effervescing Experiments and Design- students experiment with different liquids. Students write a conclusion for the experiment.

Time to Write a Conclusion

Ultimately the reason for the experiment is to answer the question from the beginning- which was” How can we make the tablet dissolve faster?

This activity also helps teach the connection between the question and the conclusion.

The photo above has the most popular wording of our conclusion, “Hot water is faster. But it will hurt you if you drink it!”

Plop Plop Fizz Fizz Effervescing Experiments- students experiment with several liquids. Student lab sheets include a data table for experiment results.

Overall, this was a big hit with my third graders! They learned a ton about variables being controlled. During the testing time, I repeated over and over which variable we were testing and which were controlled.  

I suspect they also just loved all that fizzing!

TIP: This is a noisy activity because of all the exclamations when the fizzing works great!

Which kind of liquid do you think will dissolve an effervescing tablet the fastest? (Hint: Hot water!) When will you try this plop, plop, fizz, fizz experiment? Click on any of the images to see it in my TpT store!

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Plop Plop Fizz Fizz Effervescing Experiments- students experiment with several liquids and then design their own experiment.