Ellen McCallie's Death Valley diary: Communication
Communication is vital to any mission. The team's challenge is to find...
Communication is vital to any mission. The team's challenge is to find alternative ways of getting the message across – Ellen and Mike try to develop a pen that can write in zero gravity.
- Duration: 10 mins
- Published on: Tuesday 18th July 2006
- Introductory Level
- Posted under: Natural History
Challenge: To make a space pen and ink. We’ll test it by lying on our backs and writing upside down for a long time.
This is actually a tougher test than writing in space, because in space there is zero gravity—no force (pushes or pulls) acting on the ink. When writing upside down on Earth, gravity pulling down on the ink works in exactly the opposite direction as we want the ink to flow, so our space pen not only has to work in space, it has to be designed to overcome Earth’s gravitational force acting on the ink.
Strategy: Mike works on the pen design. I hit the road to find plants that will give rich, permanent ink colours.
We’ve made inks and dyes in other Rough Science challenges, but never in this region, nor in the desert. Thus, it is, once again, a legitimate challenge. The issues are:
Finding appropriate plants - it is not as if there is a map with plants marked on it. I have to go to areas (habitats) where the specific plants I want are likely to grow well and then hunt around. If what I’m looking for isn’t there, I go to another location with similar environmental conditions and look there. I always keep my eyes open for species I may stumble over that I hadn’t considered but would work well.
Extracting the chemical components of the plants that have colour and will “stain” paper - this usually involves boiling plants in water for anything from 30 minutes to several hours.
Concentrating the ink - this is tougher than one would think. Yes, boiling off water is the starting point, but the plant components that work as inks are sometimes so dilute in the plant that tons of plant material is needed, so boiling takes a long, long time. Dyes don’t have to be as concentrated, nor do they have to be thickened, to work reasonably well, so many plants which give a nice colour as a dye just can’t be practically concentrated as an ink. Inks are tougher to make.
Thickening the ink without diluting the colour such that it flows onto the paper without running all over the paper or leaking out of the pen. Yet, the ink still has to flow through the pen—this is a real give and take.
The immediate plants that come to mind are seablight, also called inkweed, and sagebrush. Inkweed was used by Native Americans to dye basketry materials and hair black. I am counting on the fact that detailed basketry painting and dyeing, as well as hair dying, require concentrated colour. These uses suggest that I should be able to make a decent ink out of inkweed. Inkweed is found in dry areas with saline (salty) soils. It is edible, but tastes quite salty, thus its other common name of seablight. The part of the plant above ground is boiled to make ink. The colour is strongest when the plant is in bud or flowering.
Sagebrush is a back-up as an ink. It was used by Native Americans as a yellow-green dye for cloth. This means Mike and I will probably have a heck of a time concentrating it as an ink. Plus yellow-green isn’t very dark in the first place. There just aren’t many ink choices around here.
As I haven’t worked with inkweed before, I’m not willing to put all my eggs in one basket. We’ll try the sagebrush, too. Sagebrush is typically found between 5,000 and 9,000 feet above sea level in dry areas. Its scientific name is Artemesia Tridentata. If you look at its leaves closely you can see that they have “three teeth” (tri=three, dentate=teeth) at their tips.
Also, sagebrush is not related to sage, which makes things quite confusing. Sages are in the mint family. Sagebrush, on the other hand, is in the daisy family. This is one of the reasons common names are sometimes very misleading!
The obvious thickener is apricot mallow, also called desert mallow. I saw it all over the place last week as it was in flower, so it should be easy to spot with its bright orange flowers that are the size of US quarters.
Other options for thickeners include grinding up the seeds of plants that Native American used to make mush, which is basically oatmeal or cream of wheat out of plants that aren’t oats or wheat. An obvious candidate is any one of the local buckwheats, but I’m pretty sure they are still in flower. It will be a couple of weeks before the flowers, if they are pollinated, develop into fruits with seeds—and I only have days, not weeks, to come up with a reasonably thick ink.
Results so far
As expected, inkweed was readily available in this dry, salty region. For sagebrush, I’ll have to go up higher in the hills. Apricot mallow is proving elusive. It has stopped flowering, and based on the one puny plant I found, it loses most of its leaves once its flowered. I’ll have to hunt for this plant based on its stem architecture and see how I do. It’s basically like looking for lost keys based on their shape.
Mike, in the meantime, has made two brilliant prototypes of pens. Both are way to big to be practical, but the science behind them is fab. One is a capillary pen that won’t even require thickened ink. The other is a version of the ball point pen. Who would have ever thought we’d make a ball point pen on Rough Science. Cool!
The boiled inkweed was a dark grey-green, not black as I expected. I’ve stirred it quite a bit, hoping that it will oxidize and turn black.
Mike is testing new versions of his pens.
I headed out to the hills in a four-wheel drive vehicle and really needed the four-wheel drive. The sound man with us (yes, we always have a camera and sound crew, plus a director with us) covered his eyes as we wound our way up a steep, narrow road complete with rocky outcrops on one side and a precipitous drop on the other. It really wasn’t so bad, but my driving was honed when I worked in the Amazon regions of Ecuador and Brazil. Slick Amazon clay with 100 ft drops on either side of the road and bridges made of two single logs barely wide enough for each tire were par for the course. They made for nerves of steel.
In any case, we made it into the hills, collected sagebrush, and were about to head out when I spotted cochineal. Granted, cochineal isn’t a plant—it is an insect that lives on certain species of cactus—but cochineal dye has been known for centuries. It was once only second to gold in terms of value. Peru exported 640 tons of cochineal last year as a natural food and cosmetic colouring, as well as for other things requiring a brilliant scarlet red. Female cochineal insects are pretty sedentary on cactus pads. Males have wings, fly around and mate with females, and die after a few days. Females live by sucking the juice out of the cactus with their mouth parts. They are covered in a white, waxy substance that helps hold in humidity, while reflecting sunlight, so they are well adapted to arid, sunny areas.
I collected as many as I could in the short time I had, before I had to get back to the mine. It wasn’t much, but cochineal is quite concentrated. I also collected one cactus pad infested with cochineal to show Kate how they live, though I don’t think I will tell anyone about them until I find out how the inkweed works out. It is good to have a surprise up my sleeve if needed.
I also found a sufficient supply of apricot mallow leaves. It was crazy, going around looking for thin stems with few leaves, but I did find one hardy plant with lots of leaves. I’ve got them boiling in water for several hours. The liquid should thicken when cooled.
I also ran across tansy mustard in fruit, so I collected its teeny-weeny seeds to grind up and use as a starch-based thickener. We’ll see which one works better in Mike’s ball point pen.
I also collected several Joshua tree leaves as possible nibs for the capillary action. The Joshua tree “forest” (it is actually more savannah than forest) is so striking, the quintessential silhouette of this area.
The sagebrush is useless as an ink.
Mike is brilliant. Because finding these plants has taken longer than expected, I haven’t helped with the pen design at all. But Mike really hasn’t needed my help.
Both the desert mallow and the tansy mustard seed thickened the inkweed sufficiently well, but the mini-version of the ball point pen just wasn’t as reliable as the capillary action zero-gravity pen, so we ditched the thickeners and worked on improving the ink color for the capillary pen.
Kate was less than impressed with the inkweed color. She said something about it being a dirty, but functional, grey. I brought out the cochineal, and she smiled. As it turned out, Mike’s capillary pens needed quite a bit of ink and I didn’t have enough cochineal to be strong enough on its own. For the final test, we mixed unthickened inkweed with cochineal. It worked beautifully—a deep purple to write “Rough Science mission accomplished!” which came through clearly on Kathy and Jonathan’s light/sound communication machine. Too bad Iain’s not a artist as well as a geologist. The plaque of Kate’s face is… well, Kate’s a good sport.
Copyright & revisions
Originally published: Tuesday, 18th July 2006
Last updated on: Tuesday, 29th August 2006
- Body text - Copyright: The Open University
- Image 'Ellen McCallie' - Copyrighted: Production team
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