Visit Your Local PBS Station PBS Home PBS Home Programs A-Z TV Schedules Watch Video Donate Shop PBS Search PBS
Rough Science
Explore the Challenges
Solve the Web Challenge
Meet the Rough Scientists
About the TV Series
Discover More
Site Map
Meet the Rough Scientists

Carriacou Diary: Ellen McCallie

Day 9 — Antibacterial Cream

This is a tough challenge; itís very interesting, too, but Iím a bit worried about a couple of things.

First, Mike L and I donít get on too well, but we both like good challenges. In the next three days, we are really going to have to focus on the work at hand, putting aside everything else. I guess this is why science is such a good cross-over sport — what I mean is people from different cultures, different religions, different languages, different perspectives can often work together if they share a common goal. Science and/or figuring out things often carries a common goal with it. Iím just going to take a deep breath, get over it and do good work. I expect that Mike L will do the same. Heck, making a microbiology lab out here will be quite a trip.

The lab equipmentIn college I laughed when we were handed agar plates. I always wanted to eat them because in high school, when I was an exchange student to Bogor, Indonesia, we would eat agar with coconut milk and other flavorings. I loved it. The texture was amazing. It was soft, but firm, I could separate the flavored layers with my tongue. It is like playing with Wisconsin string cheese!

It took me seven months to finally understand what agar was — a seaweed algae that has been cooked down. The polymer chains (carbon chains) in agar change their structure depending on their environment. Basically, when the seaweed is in calm or deep water, the polymer structure of agar is a soft gel, allowing nutrients to be absorbed into the seaweed. When the tide goes out and the seaweed is exposed (and bashed by waves hitting them and rocks), the polymer structures in agar change; they add sulfate groups which cause cross-linking. In any case, the gel becomes firmer and protective.

Our goal is to induce the hard gel properties, so we have a firm medium on which bacteria can grow. The food industry often uses agar in the soft gel form to make foods smooth and creamy.

It isnít any seaweed that forms agar, however. It is a red seaweed, that often looks brown — just my luck — and looks like it has two-fingered hands at its tips. This is nuts. Iíll just have to go diving to see if I can find some.

Dr. Fran Hanzawa, a professor of mine while I was at Grinnell College, once told me her Major Professor told her to go find seedlings of Trillium grandiflorum. He didnít know what they looked like, but she should go find some. This is how I feel, even though I have a clue as to what the seaweed looks like — I have a whole ocean to search.

Day 10 — Antibacterial Cream

I found the right seaweed (Chondrus crispus). Iíve boiled it up (and boiled it and boiled it). I never realized how much biology and chemistry depend on heat. Heat causes reactions and speeds up reactions. Weíve got gel to add bacteria to. The meat broth I made is to give the bacteria nutrients so they can multiply.

Day 11 — Antibacterial Cream

Why try garlic? Surely, you must have seen the ads that claim garlic will cure you of anything and everything. They have been advertized for at least two hundred years. Plus we know garlic is safe for human consumption, even in high quantities — my college friends are a case in point. We even ate garlic ice cream thanks to a buddy of mine, Rob White. So is garlic the miracle cure? Letís start by seeing what it does to bacteria.

The oil from wild sage is known locally as a bacteriacide — "kills germs". Why not test it!

So why yucca? (It is actually agave (Agave caribeaicola), but once you goof and say it wrong all day on television, you have to stick with your mistake. It is too hard to correct. This is reality TV after all.)

Agave, looks like a big aloe plant and it is also fairly closely related to aloe. Aloe is known to promote healing. That doesnít mean it kills bacteria, but I was curious to see what it would do. These are long lived plants that seem to have few infections and blemishes on them.

The biology labWe made three replicates. In other words, in order to have confidence in our results we tried everything three times, just in case one (or more) of our tries ended up strange. For example, what happens if I thought I dipped the pipette in the wild sage, but I actually dipped it in the yucca by accident and didnít know it? The results for that plate would be inaccurate, but I wouldnít know it. The liklihood of me doing the wrong thing three times is much less than if I only did one try of each thing. 'Minimizing the likelihood of errors' or 'improving accuracy' — thatís why we make replicates ('repeats').

Why did we use a control? What is a control anyway? I think of a control as what would happen if you didnít do anything. In other words, we grew bacteria on agar plates with beef broth for bacteria food. If we didnít put a bacteria-killer on the plates, what would we expect? (Tons of bacteria to grow.) A set of control plates with lots of bacteria lets us know that everything is going as it should. If the control plates didnít have bacteria, then weíd know something was wrong with the agar, our sampling of bacteria from Mikeís mouth, or something else. The important thing is that we wouldnít make the mistake of saying all the treatments, garlic, wild sage oil, and agave, are great at killing bacteria. Weíd know there wasnít bacteria there in the first place.

Okay, so we have control plates to make sure everything is as expected and also to see what happens if you donít add a treatment.

As it turns out, our results were pretty consistent among plates of each treatment (each thing we tried). The garlic was the best in all three of its plates, then the wild sage oil, then the agave, and then the control plates which were covered in bacteria.

Hey, this challenge worked out okay! And wasnít Kathyís microscope the coolest thing ever!

Day 14 — Kite

Heck, I can make a kite — at least it will look like a kite — but I donít think Iíve ever flown one. This may be a great disadvantage — I wonít have much insight into what modification to make if it sort of flies. Also, this kite is not going to be made of homemade paper. I think Iíd have a mutiny if I even suggested it — too much work!

So up the coconut tree I went. I originally saw people climbing trees while doing botanical research in the tropics. Some of the guys who lived along tributaries to the Amazon would climb various palm trees to get the fruit. Theyíd wander into the forest, find a vine, wrap it up, and then scoot up a palm tree. Yes, some palms, like coconut palm trees, you can "walk" up, but others are too smooth. I wanted the fruit of acai and other smooth-trunked palms, so I learned the vine method of climbing by watching.

Setting up a shot of EllenI forgot to sharpen my machete before Kate and I hit the forest, so it was pretty pitiful when it came time to cutting vines. I can imagine every botanist, farmer and forest lover just laughing and shaking their heads watching me hack at vines with my dull machete. At least Kateís was better. She also learned fast.

When it came time to filming the collection of the coconut fiber, I headed up the tree. It isnít difficult, but it does take quite a bit of muscle. Iím always thankful that my parents got me involved with cross country running starting when I was eleven. Not only did it keep me out of trouble all the way through high school, it has also provided me with a fitness foundation. I am not fast, but I am strong and reliable. My lungs and legs have stamina. My arms on the other hand...

I was doing the best I could holding on, hacking with my machete to cut the fiber sheaths that surrounded the coconut flower. In rock climbing we are always told to have three points on the rock, but it just wasnít working. I needed two hands — one to hold the fiber sheath and the other to hack at it. It was safe as long as I was squeezing the palm as hard as I could with my feet and thighs. The blood kept draining from my hands and arms, though. This hurt. Sure, for some this would have been a piece of cake. For me, it was hard. Iíd actually never done it before. Iíd watched guys climb many times. Iíd never seen a woman do it, nor had I done more than one or two "steps" up a palm.

Here I was climbing and hacking with this film crew watching. When I couldnít stand it any longer and my legs were shaking I started to head down. Drew called up that he was out of film, could I wait a minute for him to change rolls or, if I had to come down, could I then go back up for a minute? That is when I really get tickled. Hey, I like to think I am making it look easy. Actually, my legs were wobbling and throbbing. There was no way Iíd make it up the tree again today — or even tomorrow. Could I hold on?

Once safely on the ground again, I quickly threw together a kite using sticks as the frame (Iíll collect bamboo tomorrow), coconut fiber as the sail and home-made thread/rope from the hulls of coconuts and agave plants. Once I proved I could make a light, but dependable, line, Kate generously gave me some. (Otherwise I would have had to put her to work making forty to sixty feet of it.)

My first attempt at a kite did not fly. I took it to Kathy and Jonathan for insight. Making a botanical kite was my challenge — and appropriately so. I just wish it were someone elseís job to make it fly.

Day 15 — Kite

The only person involved in the show that flew kites was Paul, one of the soundmen. Though I tried and tried, I never got the kite up for more than three seconds. Paul got it up for ten to fifteen seconds, but he could never pass the string along to me. He said that the wind was really gusty.

So what makes a kite fly? Heck, I donít even know how to think about this. The frame needs to be sturdy but flexible. The sail needs to be strong and smooth. How important is smooth?

Ellen workingThere was a lot of controversy about the tail — one tail or many? A long tail or a heavy tail? Is the tail for balance or not? How do I figure this stuff out? I donít think about making kites very often at the Missouri Botanical Garden. Okay, lift happens when air on one side of the sail (or wing) is moving faster than the other side. The faster side has less pressure, so the sail gets pushed up — or is it the other way around? I can tell you how levers work. I can explain the gears on a bicycle. Why didnít I spend more time in front of the airplane exhibits in museums? It sure would have helped me now!

In any case, bamboo is an amazing plant. It grows in many parts of the world. It is actually a big grass. Its leaves can be as sharp and painful as a serrated bread knife. Because the fibers of bamboo are relatively long and the stems are hollow, bamboo is strong, flexible, and light. Iíve seen it used as scaffolding all over Asia, even to build skyscrapers. Yet the young shoots of bamboo are edible, both to pandas and humans, though I donít know if we eat the same bamboo species.

Also, coconut palms are considered "life trees" because they meet so many of our needs as humans. The coconuts provide nutritious liquid when "young" (immature fruit). The mature nut has calorie-rich flesh, full of life sustaining fats. The fruits float. The coconut hulls are made into ladles and other utensils. The fronds are great for shade, making baskets and probably much more. The husk fiber can be twisted into a strong rope. It is almost as if that any need one has, coconut can help meet it.

I also poked a hole in acacia thorns to make needles to sew the sail of the kite.

Day 16 — Kite

Iím not sure how I feel. Was this a success — waving a kite on a long stick? Are gusty tropical winds dependable? Should geeky kids, like I was, be forced to gain practical life experience even if they donít want to, so they know more about all sorts of things? All I can think of is this great photo of my grandfather lying on the ground, his eyes shut and flying a kite by holding the string in his teeth.

My brain has just never worked very well when dealing with the physics of motion. Some people pick it up quickly. I had to force myself through it, no pun intended. When I get home I think Iíll get some flying toys and just play with them. The kids in the neighborhood will join me. Maybe they can teach me what makes things fly and why.