Sunday, April 7, 2013

LMAYQ: Scales

The word "scale" can mean many things, and The Internet can't yet use context to tell the difference. So for this issue of Let Me Answer Your Questions, here are questions about scales that The Internet thinks The Cellular Scale can answer. As always these are real true search terms, and all the posts in the LMAYQ series can be found here

A Question of Scale (source)

1. "Can you give a rat scales?"

 I have never thought to ask this question, but it is an interesting one. If you can grow weird things on mice, like ears, then why not scales? Well here's the thing, the 'ear mouse' is growing skin like it normally does, the skin is just growing over an ear-shaped mold. It would actually be harder to make a rat grow scales. If it is possible, it would take some mastery in genetic manipulation...

Bee-Rat, the ultimate achievement in genetic manipulation (source)

Some sniffing around on wikipedia taught me that scales have evolved several times (fish, reptiles, arthropods, etc). It might be possible to make a rat (or mouse) grow scales by isolating the scale gene from these other animals and inserting it into the rat genome. However, since rats already grow fur, teeth, and nails, which are related to scales, it might be possible to manipulate those features already in the rat to become more scale-like.

But to answer your question, no. I am pretty sure we can't give a rat scales yet.

2. "Does the giant squid have scales?"

Another interesting question. The quick answer is no, giant squid and colossal squid (like their normal squid counterparts) have smooth skin that does not contain scales. This isn't too surprising because squid aren't fish, they are cephalopods (like octopus and cuttlefish). Cephalopods sometimes have shells, but not scales. 

Zoomed in view of Squid Skin (source)
Instead of protective scales, cephalopods use pigment in their skin to camouflage themselves or confuse predators.

Blue Octopus, Eilat Israel (I took this picture)
This octopus turning blue sure confused me.

3. "How to turn your cell phone into a scale."

There are a couple of ways that you might think a cell phone could be used as a scale. One is by the touch screen sensor. However, most smart phones now have capacitive touch screens which respond to the electric change your finger induces on the screen. That means that the amount of pressure applied doesn't matter. So you couldn't use a smart phone as a scale in that way.

Another way is through the accelerometer. Smart phones also have accelerometers, which you could possibly use to measure the force of something moving. But this wouldn't tell you the mass of the object unless you already knew the acceleration. (force = mass * acceleration). 

But really the only way that seems to actually work (albeit slowly and with questionable accuracy) is using the 'tilt sensor' of the smart phone.

But really you just as well make your own if you are weighing out small amounts of something.

Most importantly it's helpful to know what some typical objects around the house weigh, so you can use them to calibrate a phone or homemade scale.  Here are some useful weights:

1. US penny 2.5g
2. US nickel 5 g
3. 1ml water 1g
4. Euro 7.5g
5. British pound 9.5 g

4. "What is the scale on the cellular level?" 

Finally a relevant question! Most cells are measured in microns, with a blood cell being about 6-8 microns in diameter.

blood (source)
Neurons on the other hand can have somas (cell bodies) ranging from tiny (5 micron diameter) to large (50 micron diameter). But even for neurons with small somas, the dendritic or axonal arbors can be gigantic. 

Some neurons in the aplysia (snail) can get up to 1mm (1,000 microns) in diameter. Which is ridiculously huge for a neuron. For perspective, C. Elegans, a nematode frequently used for neuroscience research, is about 1mm in length. The whole animal! Including its 302 neurons! 

© TheCellularScale

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