Field of Science

Astronaut Training

The Midstate California Fair is on in town. Last year we went to see friends ride in a roping competition and the bull riding. This year, we did the rides. Crash Kid's undoing was the Gravitron, which runs at 4 G. The ride was developed based on the centrifuge used by NASA for astronaut training. According to Crash and his sib, there is no sense of movement inside, just a feeling of weight and the ability to climb the walls or hang upside down. They also report that while once is fun, twice risks the stability of dinner.

The Real Thing

Astronaut Walter M. Schirra Jr. prepares to enter gondola of centrifuge which is used to test gravitational stress on astronauts training for space flight. Schirra became the pilot of the Mercury-Atlas 8 six-orbit space mission. Photo is public domain from NASA.

Sink or swim?

It's been hot in the coastal foothills of California (afternoon highs ranging from 102 to 107F), and we've been cooling off in the pool and with a steady supply of cold drinks. But the search for truth marches on, even on vacation, and in that spirit we did a little experimentation this afternoon. Does Diet Coke ™ really float, while the high calorie stuff sinks? Not having any on hand, we substituted Diet 7-Up and Sierra Mist (non-diet) and dropped away. Sure enough the diet stuff floats.

Why? The cans are the same size, but the non-diet soda weighs more. Why? Do calories have mass? One of my brothers suggested it was because sugar is a heavier molecule than aspartame (NutraSweet ™). This is true - sucrose weighs in at 342.3 daltons while aspartame comes in just under 300 (294.3 daltons), but not the solution to the mystery. The relative sweetness of the two molecules is the key. You need less than 100 mg of aspartame to equal the sweetness of the roughly 40 g of sugar in the regular soda. Both have the same volume of solution, the sugar one is denser than water and sinks. But wait...why isn't the diet stuff denser than water, too? It should be just a little heavier than just plain water not? True, but the air bubble in the top of the can is just enough to offset it.

A holiday at the intersection of biology and chemisty

I'm on vacation in California taking care of my dad's 10 acre farm while he is out of town. The resident fauna include 2 watch llamas and a small flock of Barbados sheep (self-shearing). When I arrived the flock had 11 sheep - now there are 16. If you're counting (and I am, every morning), that means that 5 new sheep have appeared. Four of them were born in the space of 2 hours a week ago last Saturday in the 107 degree heat of the afternoon. Birth is a messy business, and in the end I sacrified not one, but 2 white t-shirts to the process.

After the biology had settled down and was nursing happily, I turned to chemistry to get the stains out of my shirt. My dad (experienced in these matters) advised no bleach, and soaking in a strong salt solution. Why no bleach? Bleach is an oxidant, and "removes" (or at least decolorizes) many stains by oxidizing the carbon-carbon double-bonds which are responsible for the color. The red color of blood comes from the oxyhemoglobin. Oxidizing the iron in the hemoglobin produces iron oxide - aka rust - not necessarily an improvement on the front of your t-shirt.

One of the new arrivals.

Organic Synthetic Mystery

My dad is a retired organic chemist, who suggested we try this reaction. So what does it make?

To a 2-L jacketed round reactor vessel (reactor #1) with an overall heat-transfer coefficient of about 100 Btu/F-ft2-hr add 530 cm3 gluten, 5 cm3 NaHCO3, and 5 cm3 NaHCO3 with constant agitation.

In a second 2-L reactor vessel with a radial flow impeller operating at 100 rpm add 235 cm3 partially hydrogenated tallow triglyceride,
175 cm3 crystalline C12H22O11,
175 cm3 unrefined C12H22O11, and 5 cm3 methyl ether of protocatechuic aldehyde until the mixture is homogeneous.

To reactor #2 add two calcium carbonate-encapsulated avian albumen-coated protein followed by three equal portions of the homogeneous mixture in reactor #1. Additionally, add 475 cm3 theobroma cacao and 235 cm3 de-encapsulated legume meats (sieve size #10) slowly with constant agitation. Care must be taken at this point in the reaction to control any temperature rise that may be the result of an exothermic reaction.

Using a screw extrude attached to a #4 nodulizer place the mixture piece-meal on a 316SS sheet (300 x 600 mm). Heat in a 460K oven for a period of time that is in agreement with Frank & Johnston's first order rate expression (see JACOS, 21, 55), or until golden brown.

Once the reaction is complete, place the sheet on a 25 deg. C heat-transfer table allowing the product to come to equilibrium.

Synthetic method reported in Chemical & Engineering News (C&EN, Jun 19, 1995, p. 100) and attributed to Jeannene Ackerman of Witco Corp.

Oxygen is a blue crystalline solid at room temperature

Twenty-five years ago I went to a seminar with this intriguing title. The photographs of a deep blue substance trapped in a diamond vise were stunning, particularly in a time when black and white slides dominated the colloquium scene. Things get even more colorful if you explore the phase diagram of oxygen at higher pressures and temperatures (beyond 650 K and 16.7 GPa). A recent paper in Physical Review Letters (PRL 93, 265710, [2004], "New Phase Diagram of Oxygen at High Pressures and Temperatures", M. Santoro, E. Gregoryanz, Ho. Mao, and R. J. Hemley) revealed new solid forms of oxygen. The ε solid phase is a red crystalline form.

What's a GPa? A gigapascal...or about 10,000 atmospheres.

Read early entrys about phase diagrams and literature.

The Boys of Summer Wear Titanium

A recent article (first published in the NY Times) notes the popularity of titanium coated necklaces with baseball players. Why? Supposedly it helps them have more energy. The necklaces are made by Phiten, and according to one of their sales representatives:

Everybody has electricity running through their bodies," said Scott McDonald, a Seattle-based sales and marketing representative for Phiten. "This product stabilizes that flow of electricity if you're stressed or tired."

Phiten says their process produces an " aqueous solution of titanium that is considered insoluble in water."

I think what they mean is that titanium metal is not terribly soluble in water (indeed true), their process "carbonizes it" (so now it's no longer the metal and it's conductivity, if you believe that is what is 'stablizing the flow of electricity', changes). If you want to wear non-metallic titanium, try sunblock containing titanium dioxide. It's cheaper, both blocks and scatters UV radiation, and the lotion base will improve dry skin!

The only flow this product is helping is the cash flow of the company selling it!

Would Ben Franklin have Blogged?

Read Carnivalesque #6 at History News Network to see Cliopatria's take on Would Ben Franklin have Blogged?, which cites a Culture of Chemistry piece on Robert Boyle's Invisible College

TV Science: I Love Lucy #36

I'm teaching a one day workshop on chemical kinetics to high school students tomorrow (part of Bryn Mawr's Science for College program). The relationship of the rate of a reaction to it's mechanism (the individual steps that produce the overall molecular transformation) is a key principle underlying the study of chemical kinetics. To explain this, one text refers to the episode of "I Love Lucy" where Lucy and Ethel work in a candy factory (while Ricky and Fred try their hands at keeping house - but that's another post. The candy boxes appear only as fast as the slowest step in the process (Lucy and Ethel wrapping) - reactions go no faster than the slowest step, called the rate determing step (or RDS).

See the clip here.