Science Buddies: "Ask an Expert"

We tried the "How Do Clouds Form? " experiment.

We used a cookie jar for the cloud chamber and the latex glove to change the pressure.
As the latex glove always breaks because of the heat in the jar, we decided to replace the latex glove by the jar lid and use the temperature as a variable.

Are we making some obvious mistake here.
Even by using the jar lid, we don't see big differences in the cloud size.
Should we use a bigger jar?

Hi etri,

I think changing the pressure is a key variable in this experiment, so you should find a way to use the glove.

Reading the procedure, it suggests that the matches are flaming when you put on the glove, so I can imagine if you used a lot of matches, this would be a real problem! I'd suggest the following, in this order: 1) Larger jar -- judging from the picture it should be about 11 inches tall or even more -- not a mayonnaise jar, but a kind of supersize jar, as suggested, "a very large pickle jar." 2) Smaller matches -- use book matches rather than wooden stick matches, which would tend to burn longer. 3) Perhaps use a more durable glove, not a flimsy see-through white glove, but the really strong, heavy type, the kind that tend to be bright yellow or blue.

Of course, don't put the glove too close to the matches --- maybe tilt the jar so the matches are on one side.

I hope this helps. Please tell us how it works out.

Bill

Using book matches was problematic as they don't burn long enough.
the smoke usually escapes the jar before we can put on the glove.

We'll try a bigger jar. On another website we've read that the jar should be 1 gallon.

Thanks for the reply.

I have tried with a bigger jar, and I really do use only 2 matches.
Only 1 time I managed to create some effect by using the glove.

Even though I realize that the glove is essential, I will be using the lid.
The experiment we are doing now is to put the jar on ice, and in boiling water.
This way you can easily see that the fog stays in the bottom when using the ice and stays on top when using the boiling water.

This is a science project for 4th grade. One of the learning parts of these kind of things is note taking.
I am encouraging my children to write down their observation, even though the experiment is not what we expected.

That is wonderful! It is so nice to see a parent taking the time to really help their children understand the scientific process. You are absolutely right about the importance of making observations. And don't worry about not using the glove. What you are doing with the ice and boiling water is a perfectly valid experiment. Depending on the amount of time you have left to work on the project, you might want to think about how this new procedure changes your children's question. You might discuss it with them if you have time and it seems appropriate.

Good work!