25 Mar STEM Challenge: Soda Can Challenge
Do soda cans sink or float? The answer may seem simple, but not so fast! There is some really cool science behind the answer and all may not be as it seems. Try this STEM challenge to find out!
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- Experiment worksheet
- A large container filled with water
- Variety of new, unopened soda cans. Make sure at least one is regular and one is diet soda. You can test as many brands and varieties as you would like, but you really only need one regular soda can and one diet soda can to do this experiment.
- Print out this experiment sheet to record your results. Pick your variety of soda cans, but make sure to include a diet soda can.
- Record if you think the soda can will float or sink based on the different types of soda and brands in the hypothesis section.
- Then test your hypothesis by placing the soda can in a large container filled with water. As you place the can in the container, check to see if air bubbles escaped from under the can. If they did the can most likely sunk. Try to see how you can change the way you put the can in the water so that there are no air bubbles and it floats Hint: Place the can very carefully straight up and down into the water and it should float! As long as you keep that air bubble in the concave bottom of the can, it will float.
- Repeat this process with different soda cans, for example, try pepsi or coke vs. ginger ale or sprite. Record your answers and see if your hypothesis was correct.
- Now try with a diet beverage! Use your sheet to write down your hypothesis and place the soda can in a large container filled with water.
- Record your results. Think about what happened to the cans, why do you think the regular soda sank and the diet soda floated?
Why did this happen?
Our cans were all the same size and volume. So what could possibly account for the difference? Sugar. That’s right. The regular sodas have sugar, and lots of it. Diet soda uses artificial sweeteners that are much stronger or sweeter than sugar, so only a small amount of sweetener is needed. The difference between the amount of sugar used in regular soda and sweetener used in diet causes a significant difference in the density of the liquids. Regular soda is more dense than water, therefore it sinks. This is called displacement. Diet soda is less dense than water and weighs less than the water it displaces, this causes it to float.
To further prove this theory regarding mass and density you can weigh the cans and find that the diet pop will weigh an average of 20 grams less than the regular pop. This is despite the cans having the exact same volume and being in every other way identical.