Posts Tagged: Science You’re Super

Science, You’re Super: Fireflies!

Fireflies

By Aryn Henning Nichols • Photo by Radim Schreiber
Originally published in the Summer 2014 Inspire(d)

You know what’s super magical? Light-up bums.

I’m talking fireflies, of course! A field or dark forest flooded with those little flickering butts is some seriously super science. It’s one of my favorite things about summer. But have you ever wondered how they do it? Or why?

First off, fireflies – or lightning bugs (whichever you prefer) – are neither flies nor bugs. They’re beetles. But lightning beetle just doesn’t have the same ring, does it? (1)

These little beetles produce a chemical reaction inside their bodies called bioluminescence, which allows them to light up. Inside their light organs, oxygen combines with calcium, adenosine triphosphate (ATP), and the chemical luciferin – all while the bioluminescent enzyme luciferase is present. This produces light. (2)

And it’s not just any light. An average electric light bulb gives off 90 percent of its energy as heat, and only 10 percent as light. If fireflies produced that much heat when they lit up, they’d probably not live through it (giving new meaning to “fire”flies). Luckily, fireflies are amazingly efficient light-producers. During bioluminescence, a hundred percent of the energy goes into making light. (1)

The firefly controls the beginning and end of the chemical reaction, and thus the start and stop of its light emission, through oxygen. Insects do not have lungs, but instead transport oxygen from outside the body to the interior cells through a complex series of successively smaller tubes known as tracheoles. When the firefly wants to light up, it adds oxygen to the other chemicals needed to produce light. When there’s no oxygen available, the light goes out. (2)

They appear to light up for a variety of reasons: to communicate their distastefulness to predators, to help identify certain types of species, or, more commonly, to attract members of the opposite sex. Yes, fireflies get right to the point in their short two-to-three-week lifespan. Studies have also shown that some female fireflies like males with high flash rates and/or increased flash intensity. Ooh la la! (2)

Unfortunately for some sad folks in a few sad regions, not all fireflies flash. Fireflies that inhabit the western areas of North America don’t use light signals to communicate. Because of this, many people inaccurately believe that they don’t exist west of the Rockies, since flashing populations are rarely seen there.

But for some lucky folks in a few lucky regions, fireflies synchronize their flashes! It’s rare – in the US, you can see this phenomenon (usually during a two-week window in late spring) at Great Smoky Mountains National Park in Tennessee – but amazing to see. Thousands of fireflies will light up at the same time, over and over, in what’s called simultaneous bioluminescence! Not coincidentally, thousands of people come from all over to witness this amazing show each year. (3)

And now, final interesting firefly fact: Firefly luciferase is also useful in medical research! It can be used as markers to detect blood clots or to tag cells and genes, and to monitor hydrogen peroxide levels in living organisms (hydrogen peroxide is believed to play a role in the progression of some diseases, like cancer and diabetes). Scientists can now use a synthetic form of luciferase – fortunately – as we’d all like to keep those little bums flashing for many years to come. (1)

Sources:

1. insects.about.com/od/beetles/a/10-Cool-Facts-About-Fireflies.htm
2. www.scientificamerican.com/article/how-and-why-do-fireflies
3. www.nps.gov/grsm/naturescience/fireflies.htm

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Aryn Henning Nichols has watched, chased, or caught fireflies every summer of her life. She may also have squished and smeared a few, and feels more than a little guilty about it, especially after writing this Science, You’re Super! Sorry, fireflies. Never again!

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Radim Schreiber, born in the Czech Republic, is an artist/photographer and cinematographer. His passion for photography began while photographing insects during his college years in Iowa. After completing his BFA at Maharishi University of Management, he started working for The Sky Factory, LLC in Fairfield, Iowa, as a nature photographer, cinematographer, and digital artist. Radim has won multiple national and international photography competitions, including the Smithsonian Magazine Photography contest. Radim’s latest project is photographing the bioluminescent glow of fireflies.

 

Science, You’re Super: Sap!

sapdrip2

By Aryn Henning Nichols • Photos by Benji Nichols
Originally published in the Spring 2013 Inspire(d)

Whether the discovery of sap was a happy (sappy?) accident or not, it has definitely revolutionized breakfast forever. Pure maple syrup is a gift from…well…the maple trees (thanks, trees!).

But just what is sap, and why do we only “tap the sap” in the spring?

Let’s get science-y right away: Xylem and phloem are the transportation systems of vascular plants ­– water and nutrients in (or up) the xylem cells, and sugars – sap – out (or down and around) the phloem calls. (1)

A plant has roots to help it absorb water, but a mature tree’s leaves can be 100 feet above the ground. This is where the xylem is put into action, circulating water and dissolved minerals to the leaves. Also, fun fact: When someone cuts an old tree down, the rings you see – one for every year – are the remains of old xylem tissue (it dies and develops anew each year). (1)

But we’re really here to talk about the phloem. Most plants have green leaves, where the photosynthesis happens. Photosynthesis creates sugars – that’s the sap! – that every cell in the plant needs for energy. You can think about sap kind of like a food for the tree and its buds and leaves. The leaves produce sugar during the summer and in the spring, when the tree draws water from the ground, the water and sugar mix inside to create sap, which helps new buds grow. (2) The phloem system transports the sap throughout the plant or tree, and is what brings it to the sap tap in the spring. (1)

The sap in sugar maple contains a high concentration of sugar compared to the sap of other trees, which why so many people go to the lengthy process of collecting it and making it into that delicious syrup. But don’t the trees need the sap? Luckily, it has been estimated that tapping removes 10 percent or less of the tree’s sugar, an amount too small to hurt a healthy tree under normal environmental conditions. (3) Also, once the buds and leaves start to open in the spring, most of the sugars have already served their purpose for the trees. (2)

So is it sap season only in the spring?

Spring is when the temperature fluctuations are just right (in a good sap year, anyway) to create a good flow of sap (although some folks may also harvest sap in fall, it’s more of a rarity). Early in the season, when the maple trees are still dormant, temperatures rise above freezing during the day but drop back below freezing at night – this creates a pressure in the tree that causes the sap to flow out through a wound or tap hole. During cooler periods, or at night, when temperatures fall below freezing, suction develops, drawing water into the tree through the roots. This replenishes the sap in the tree, allowing it to flow when it’s warm again. Too hot or too cold temperatures during the short, six-week “sap season” reduces the amount of sap flow and makes for a “bad year” for maple syrup producers in that region. (3) A really good maple tree can produce sap for 100 years, and one healthy tree can produce up to 15 gallons of sap a year. (2)

The most common use of maple sap is to process it into maple syrup. To make maple syrup, the excess water is boiled from the sap. It takes 40 parts maple sap to make 1 part maple syrup (10 gallons sap to make 1 quart syrup)! (4)

Although Vermont produces most of the nation’s maple syrup, you can check out the process locally at Green’s Sugar Bush (1126 Maple Valley Road, Castalia, Iowa) or see if there’s a sugar bush near you that allows visits!

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Aryn Henning Nichols enjoys heading out to her old stomping grounds for pancakes at Greens Sugar Bush in the spring. The line is often long – stretching all the way down the driveway – but that’s often the fun! You stand out in the spring air and chat with the person next to you about nothing or everything. Or the weather – it is the Midwest!

1. www.biology4kids.com/files/plants_xylemphloem.html
2. minnesota.cbslocal.com/2012/03/27/good-question-whats-in-tree-sap/
3. maple.dnr.cornell.edu/produc/sapflow.htm
4. www.tapmytrees.com/coprsap.html

Science, You’re Super: Carbonation!

Carbonation

By Benji Nichols

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In honor of Wisco Pop making its recent debut in bottles, we thought we’d bring you a little Super Science about carbonation!
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Fizz – it’s the stuff of magic. Just think where our refreshments would be without all those bubbles! Whether it’s a craft brewed soda, sparkling water, refreshing beer, or even champagne, carbonation is something we probably take for granted. Maybe that’s because man-made forced carbonation, as we know it, has been around for about 250 years. In 1767, British chemist (and theologian/inventor) Joseph Priestly was credited with discovering a method of pressurizing water with carbon dioxide. By suspending a bowl of water above a brewery vat of beer, the offshoot ‘fixed air’ (full of CO2) infused the water with carbon dioxide bubbles. Of course, naturally fermenting substances have been fizzing since well before written records – giving off their own carbon dioxide as yeasts metabolize sugars, and if kept under pressure, naturally producing carbonation as well.

But most sparkling beverages that we are familiar with in today’s world are supplemented with man-made carbonation. Gasses can dissolve in liquid, and carbonation is created when carbon dioxide (CO2) does just that. The process of dissolving carbon dioxide in water is done under pressure, in which the CO2 gas will dissolve until the amount of CO2 in the air and in the water are equal. Excess CO2 can be added when under pressure – which is why when we open a canned or bottled beverage we hear a small ‘whoosh’ of pressurized CO2 exiting the vessel. As long as the container is sealed again, the CO2 will not entirely leave the liquid, but as everyone knows, if you leave a carbonated beverage sitting out for too long, it goes flat. (Sad panda…) Large industrial bottlers have the ability to add much more pressure in the process, thus providing an even more intensely carbonated beverage than, say, an ‘at-home’ carbonation kit or soda fountain, but technology and commercialization have made even small scale countertop units quite inexpensive.

So why do we like the bubbles? First, the bubbles are pressurized bits of carbon dioxide surrounded by water molecules – and when the pressure of a bottle or can is released, the bubbles seek to create an equal force between the liquid and the air that is around it – thus, rising to the surface in beautiful little pearls and fizz! It has also been found that CO2 bubbles actually hit the ‘sour’ sensory area of the human tongue, making them have some sense of ‘taste’ that we generally enjoy. If you’ve ever taken a drink of flat soda water or similar, then you know that the taste is not particularly pleasant. There are different types and sizes of CO2 bubble as well, and the taste and mouth feel of something that is naturally carbonated (fermented), versus that of something that is pressurized can be noticeable. For instance, some sparkling wine and champagnes have extremely fine bubbles that continue rising to the surface for some time, while soda generally has larger bubbles that don’t last as long. Another amazing figure is that a glass of soda basically holds roughly one glass of water, but that would equate to five glasses of CO2 as bubbles! Any way you experience it, carbonation adds a joy to beverages that is truly delightful – and a little magical! Cheers!

Sources:

  1. mattson.creighton.edu/SodaWater/SodaWater.html
  2. en.wikipedia.org/wiki/Carbonation
  3. www.grit.com/food/kitchen/carbonation-science.aspx
  4. www.nytimes.com/2009/10/20/science/20obfizz.html?_r=0