Explain the task to each other again in your own words.

State what you understood the task to be and what is still unclear to you.

We’re supposed to find an explanation for why sparkling mineral water fizzes after being shaken, or when we sprinkle salt, sugar, or sand into a glass of sparkling mineral water.

Recall what you know about sparkling mineral water. What gas does it contain that makes it bubble?

Sparkling mineral water contains a lot of carbon dioxide. If you shake a bottle and then open it, the carbon dioxide forms so many bubbles that the water sprays out.

In order to clarify how the bubbles form, it’s best for you to start with one of the two experiments: sprinkling a solid in sparkling mineral water.

What can you observe?

Tip: If you conduct the experiment again, toss just a few grains of the solid into the sparkling mineral water.

We observe that gas bubbles form on the grains of the solid.

The more grains we toss in, the more vigorously the bubbles form.

Now conduct the experiment in which you shake the closed bottle. Where do the gas bubbles form in this case?

Tip: If you conduct this experiment again, place the closed bottle on the table after you shake it and observe it for half a minute before you open it. Then open the seal and look closely to see what happens in the liquid.

We see that after the bottle is shaken, many small bubbles are in the liquid.

When we open the seal, we observe that large bubbles form where before there were small bubbles.

Now try to generalize your observations from the two experiments.

After the bottle is shaken and opened, gas bubbles form from the small gas bubbles in an explosive manner.

When a solid is sprinkled in, gas bubbles form on the solid grains.

In both cases, something has been added to the water that triggers the formation of gas bubbles.

Now you have all the information you need to answer the question.

By the way, the solid added to the water and the small gas bubbles are called “nucleation sites” for the formation of the large gas bubbles.

Shaking the bottle or sprinkling in a solid creates nucleation sites for the formation of gas bubbles. Ultimately, these nucleation sites cause the sparkling mineral water to “fizz” – if external pressure doesn’t prevent this.