Nora Evelyn

As a follow-up to our liquid and solid water experiments, Nora and I decided to investigate steam. When you leave a glass of ice water out on the table why does the outside of the glass get wet? Why did the beaker in our previous experiments seem to leak without losing any mass? We explore this question by heating liquid water and then attempting to cool it quickly to see if it is possible to observe the relationship between liquid and gaseous states.

Method
We boiled a pot of water (to make lunch, this is opportunistic science) and observed (carefully, without touching the pot) that steam began to rise from the water when the temperature got above about 100º C (212º F). The senior researcher filled a heat-resistant glass with ice (figure 1) and wiped the exterior with a dry paper napkin to verify that the glass was dry. The junior researcher then held this glass above the pot of boiling water for approximately 1 minute (figure 2).

While the glass was suspended over the steam it was observed that water quickly collected on the glass and was beginning to drip off. Then the senior researcher got distracted by something happening in the living room. The glass was subsequently removed from the steam, wiped with a dry paper napkin (figure 3), and the collected water was observed directly (figure 4).

Conclusions
It seems highly likely that adding heat to liquid water can cause it to transition into steam. This was confirmed by removing heat from the steam and observing the transition back to liquid water when the heat was removed by the ice. Additionally, the ice in the glass had begun to transition from the solid ice form to liquid water, an observation consistent with our previous findings. Most importantly, this experiment was really fun (except for the boring waiting) and Nora says she wants to do it again!

Nora recently noticed that ice in one’s water or tea appears to ‘melt’ in the cup; this change is particularly noticeable when one is drinking outside on a hot day or starting with very warm tea. What is really happening? To explore this question we recently designed and executed a simple experiment to investigate 2 different states of water: liquid and solid.

Method

300 grams (approximately 500ml) of chopped ice were placed in a beaker which was then placed by the senior researcher on her monkey placemat on the kitchen table. The apparatus was left in place for a 24 hour period during which time the researchers engaged in such scholarly activities as napping, eating bunny crackers, going to school, and playing with toads.

At the end of the 24 hour period the apparatus was again consulted. It was discovered that the ice in the beaker had been entirely replaced with water. The junior researcher encouraged his daughter to feel the water and she reports that it was “not cold!” In fact, the water was 23º C (73.5ºF). The level of this water was approximately 300ml. In figure 2 we see a photograph of the senior researcher painstakingly carrying the apparatus from the table to the kitchen scale.

It was discovered that the water in the beaker (after subtracting the mass of the beaker itself) weighed 301 grams. It was observed that a large amount of water had accumulated on the monkey placemat and on the outside of the beaker itself. The senior researcher surmised that this external water was due to “it’s leaking, daddy!” but no source of leaks could be detected.

The apparatus was moved to a self-contained isolated heat removal and humidity reduction unit (colloquially, “the freezer”) for another 24 hour period and the researchers went to go play the princess game.

When the additional 24 hour period had elapsed, the vessel was found to contain a quantity of ice! A visual inspection revealed no liquid water. The temperature of the material in the beaker now registered at -9ºC (15.8º F). The ice now lacked the airy, cube-like separation of the original ice. Indeed, the top level barely reached 350ml (down from an initial 500ml).

Conclusions
It seems clear that the removal of heat from a vessel of water is highly correlated with the presence of ice in that vessel. Similarly, the addition of heat (even room temperature heat) is highly correlated with the presence of liquid water in that vessel. More rigorous studies will be required to determine the exact transition temperature at which this state change occurs but the researchers are confident in the assessment that our freezer is probably too cold. This last observation is supported by extensive longitudinal data indicating that ice cream from our freezer is “too hard” and “has to sit on the counter for a while before you can scoop it”.

Future work
The experimenters hope to return to the question of the mysterious leak. Where could that water on the monkey placemat have come from? In a possibly related question, what would happen to the water (or to the ice) if it were to be heated to a temperature much higher than room temperature using our localized conductive electrical heat application device (the stove). Much work remains to be done in this area.

Sunday, January 16th was Nora’s 3.14159265th birthday. We celebrated by going out for Buddy’s Pizza with Granny and then coming home to cuddle and watch the Muppet Movie*. Here’s a shot of me and the birthday girl watching Kermit & friends (and a shot she took of Kermit).

*Actually, this is a miserable lie. We did these things, of course, but I’d completely forgotten the occasion was coming until Danny reminded me it had passed. I’d planned to bake a pie and put a candle in it and sing but, luckily for Nora, I got busy with grad school and forgot. Oh well.

One of the things we did on our recent trip to Chicago was visit the Museum of Science and Industry. There was a LOT going on there, most of it over Nora’s head (literally!), but there were a few things she enjoyed:

There’s a risk this post will sound too much like I’m bragging. I guess maybe I am, but the real point is to put it somewhere that I (and, much more importantly, Nora) will find it again someday. Nora’s favorite question is now, “Why?”

It had to happen some time and, if her parents are any indication, we’re in for a whole lot of “why?” (much of it snarky) over the next few decades.

Many of these current “why?” questions are excruciating and unanswerable (“why is paint?”) or bizarre (“why are these my shoes?”). I thought I had her when she said, “Daddy, why are you?” and I said, “I am because I think, love.” But, without pausing, she put Descartes to shame, “why do you think?”. Drat. She’s too smart for me already. In a related question answering session she asked me, “what is the opposite of you?” and I told her, “a lawyer.”

This weekend we were at the grocery store and, in the checkout lane, she asks, “Daddy, why is there summer and winter?” I thought, “ah ha!! I know this one, I can totally do this.” So I explained that the Earth is a giant ball that spins every day. The spinning is what we call day and night, but the axis of this spinning is tilted with respect to the plane of our orbit around the Sun (demonstrates with convenient apple and stem). The result is that one part of the planet gets more sunlight, more directly, and for longer periods of time every day than other parts. Which part this is changes progressively throughout the year and this causes the seasons. I explained, for example, that this summer when it was hot and sunny here her friend Salomé was experiencing winter in Bolivia.

Now I don’t expect a nearly 3 year old to get most of this. I give full answers to questions because I like to and because I want her to feel loved and respected or some junk; she seems to eat it up and it’s crazy fun trying to explain the ecliptic to a toddler. At the end of my explanation she did the little nod that she often does, but the man in front of us in line, whom I had not noticed was listening, gave a very thoughtful and pleased “huh!” with intonation that said, “so THAT’s how that works.”

Public service accomplished. :)

Nora was eating cheese and crackers today while I made her lunch. She picked up one of the crackers, snapped it in half along the diagonal, and exclaimed, “daddy! 2 triangles!” and made me go look at them. I showed her the right angles and tried to explain a little bit about the lengths of the three sides. I appreciate that she doesn’t get a lot of this stuff, but knowledge is cumulative and has to start somewhere. It was pretty cool.

So later we’re eating our lunches and she gets this excited look again and says, “The top of the cup is a circle!” and showed me with her fingers by tracing a circle in the air parallel to the top of the cup. I was blown away. I explained that if you take the intersecting plane out of parallel with the table top then the slice it makes in the cup is an ellipse rather than a circle. She nodded and said, “and the cup has MILK!” and then she poured the milk all over herself.

The first annual Purple House Pi Day celebration was called on account of illness yesterday. Today, though, everyone is feeling better and we’re all decidedly in the mood for pi. So here’s how the new tradition works:

1. bake a delicious pie
2. measure its circumference
3. measure its diameter
4. divide the circumference by the diameter
5. see how close we can get to π
6. eat the pie!

We got 79.5cm circumference and 25.3cm diameter or a ratio of 3.142292. Not bad for our first try!