NathanUT

Sweet! I think that will settle it. Thanks for the response.

OK, I feel confident I know the answer to this, but my colleague refuses to accept my explanation. It's silly since the answer to this is not all that relevant, but as a teacher, I want to be sure I am not teaching concepts that are technically incorrect... That being said, I believe water vapor & steam (steam is a common type of vapor, right?) are totally invisible. The argument/common misconception is that you can see steam in the form of the little white cloud rising above a tea kettle or steam vacuum. It is my understanding though, that the little white cloud is just that... a cloud. And a cloud is water in liquid form that is coming together & condensing, but not yet dense enough to fall. It is my understanding that when you boil water in a tea kettle, the vapor is invisible. However, as it moves farther away from the source of heat, the vapor starts to cool and condense into liquid drops. Those liquid drops are what you see, NOT water vapor. Can anyone confirm? This makes perfect sense to me, but I can totally see why there is such a misconception on this topic. Steam cleaners put out a white cloud of steam, and steam is water vapor... so water vapor must be visible

That's pretty much what I was thinking, I just wanted to get at least some confirmation before I taught it to my kids. Thanks so much for responding!

I am teaching density in my 5th grade science class and came across an intriguing question. We made a density column and noticed something interesting. The top layer of our density column is isopropyl alcohol colored blue. The layer just beneath it is some vegetable oil. What we noticed is all the layers separated in a flat line... except the blue alcohol. It dipped down into the oil layer as though filling a bowl. I speculated to myself that this might be the result of the oil bonding easier with the graduated cylinder than itself, causing a meniscus, and the less dense alcohol just filled in the space. Is this what's happening? Can there be a submerged meniscus? Actually, I know there can be (ocean layers separated by density differences in temperature and salinity are certainly not always flat), I'm just wondering if that's what's happening in this case. One of my students noticed the same thing, so we discussed & I asked the class for ideas. I was really impressed that one student also wondered if it was a meniscus. Whether we're right or not, I complimented her on thinking like a scientist. So cool! But I promised the class I would research it & try to give them a definitive answer. Little help?!