Welcome back to the blog for another iteration in our Summer Reading series: Reading is Elemental. This week we are looking at a really broad subject: Salt. You'll never look at your French fries the same way again.
A Few Grains of History
We humans have an interesting relationship with salt. This mineral, primarily consisting of Sodium (Na) and Chloride (Cl) atoms sharing a weak covalent bond, is often combined with other elements such as Calcium and Potassium. Salts are the resulting product of a neutralization reaction of a strong base and weak acid, like your traditional baking soda (sodium bicarbonate, base) and vinegar (acetic acid) volcanoes from elementary school. Though I wouldn't eat the result if I were you!
Humans require sodium as a nutrient, but we cannot manufacture it within our bodies, which means that in order to get it, we have to eat it. In the body, sodium regulates our water balance, helps manage our body's pH, and is active in the absorption of other nutrients in the small intestine.
The reason that salty foods like French fries and chips taste so good to us is, because we have evolved to seek out salty foods to stay alive. This is problematic now, because just about all of our prepared foods have salt added to them for seasoning and as a preservative. The key for humans to stay healthy now is to have the appropriate balance of salt.
Salt has also been important in the development of human civilization in a variety of ways (See the above clip from the History Channel). Most notably, as a key component to food preservation, salt helps to kill disease-causing bacteria in our food. It does so by drawing enough water from bacterial cells to stop cell reproduction.
There are a few different ways that salt can be produced for human consumption--mainly through evaporation from saline or seawater and by mining mineral deposits. Like any other commodity, nations close to the resource have an economic advantage. As a valuable spice, salt has been a traded commodity, a form of currency, and even caused war between nations.
Salt is currently receiving a bit of attention because of growing fresh water scarcity. According to the USGS, less than 3% of the Earth's water is fresh, the only water that can be used for hydration. A decreasing amount of fresh water is available due to a current recession in glacial waters and icecaps and over irrigation in agriculture, which reduces groundwater aquifers. Scientists are now turning toward advances in technology that allow us to yield fresh water from salt water.
Sounds easy enough, right? Just take out the salt. The process is actually fairly complex and takes a tremendous amount of energy.
Low-Tech Home Experiment
Here is a simple low-tech science experiment that will allow you to use passive solar energy to distill your own water (this video is brought to you by the St. Louis Science Center). Give it a shot. Readers and fans of the hit 2012 film adaptation of Yann Martel's Li of Pi will notice that this process was used by young Pi to get fresh water on the lifeboat.
Keeping with the theme of this week's earlier post on nonfiction, here is a great read that looks at the natural history of salt and the important role that it plays in the development of human civilization. Check it out from your library: available as hardcopy and as an eBook.
Welcome back to the blog for the next installment of our summer series on the elements! This week we will tackle an important element that is crucial to the growth of virtually all plants and animals on Earth--Nitrogen (N).
Plants and animals alike depend on Nitrogen to promote growth. Plants use Nitrogen in chlorophyll molecules, which are a primary component in photosynthesis. All amino acids contain Nitrogen, and animals need amino acids to synthesize proteins and convert energy for growth and function.
Our atmosphere is approximately 78% Nitrogen, which sounds like there is an abundance of N available for plant and animal productivity, but atmospheric Nitrogen (N2) is unusable by plants and animals, because the N atoms are bound together in a triple bond. For uptake by plants and animals, N2 has to go through a series of conversions.
Nitrogen Fixation - N2 is converted to NH3 (ammonia) by lightning strikes and soil-dwelling, symbiotic bacteria living on leguminous plants.
Assimilation - nitrate (NO3-) and ammonium (NH4+) uptake from plant root hairs in soil
Ammonification - plant and animal waste (detritus) is converted from organic matter into ammonium
Nitrification - conversion of ammonia to nitrites (NO2-) which is then oxidized to nitrates by soil living bacteria
Denitrification - reduction process of nitrates back into atmospheric gas (N2) by bacteria in anaerobic conditions. This last portion of the process is important, because it keeps the cycle in balance.
Agriculture is heavily dependent on the productivity of soil for plant growth. Starting in the first decade of the 20th Century, scientists started synthesizing ammonia by combining atmospheric N2 with Hydrogen gas (H2)--usually derived from methane (CH4). For more on this process, see Haber-Bosch.
While this process creates a readily accessible form of Nitrogen fertilizer for farmers, it can potentially impact the environment in a harmful way. Excess fertilization with Nitrogen and Phosphorus can wash out of farm fields and end in up in water systems.
An overabundance of these fertilizers can lead to a rapid genesis of potentially harmful algal blooms in waterways. Phytoplankton varieties of algae are plant species and react similarly to fertilizers as terrestrial plants would. This rapid growth can cause an over-use of dissolved oxygen in the water creating a hypoxic aquatic ecosystem, forcing out other organisms.
The take home message when it comes to synthetic Nitrogen fertilization is: balance.
Getting to Know the Nitrogen Cycle
One great way to experience the Nitrogen Cycle for yourself is to start a compost heap. The key to a successful compost operation is balancing the relationship of elemental components, or stoichiometry. Creating a Nitrogen-rich compost heap will allow you to safely fertilize a garden while participating in the Nitrogen Cycle.
For more on composting, be sure to check out Let it Rot!, a capstone volume on composting, and other eBooks at your library.
Welcome Back to the blog for the next round in our Summer Reading series: Reading is Elemental. This week we will be looking at photosynthesis, an extremely important chemical reaction to all life on Earth.
(source: Wikimedia Commons)
Last week in our discussion on energy, we briefly mentioned that plants are able to convert the sun's energy into plant mass, now let's look at that process, called photosynthesis, in better detail.
Photosynthesis: a Chemical Reaction
The illustration above shows a simplification of what is happening in the natural world involving photosynthesis. We see that the energy from the sun's light (photons) creates a chemical reaction that combines (synthesizes) Carbon dioxide (CO2) and water (H20) to create some form of carbohydrate sugar (CH2O)n and leftover Oxygen (O2).
We list the equation out below, so that you can see the overall process. In our balanced reaction, we see that glucose (C6H12O6) is our representative of a carbohydrate. The important thing here is that the byproducts of this process are extremely important for life on Earth. We have to ingest carbohydrates and oxygen to have energy to live. When our bodies metabolize carbohydrates like glucose, we oxidize sugars to release energy for physiological movement (putting our bodies in motion). The byproduct of this process is CO2 which can then be stored again during photosynthesis.
For a more in depth look at the various types of chemical reactions, check out the Khan Academy video series.
Bringing It All Back Home
Again, what does this have to do with technology? Last time, we saw that when fossilized carbohydrates (hyrdocarbons--CnH(2n+2)) are burned, stored energy is released in the form of heat. That energy is converted into electricity that powers our electrical devices. The photosynthesis of hydrocarbons is the foundation for our electrical power.
For plants to continue to grow, they need balanced access to the key components of photosynthesis: water, sunlight, and Carbon dioxide (other elements like Nitrogen, Phosphorus and Potassium are crucial as well as you shall see later this summer). That balance is the basis of all gardening and agriculture. There are quite a few resources out there to help people find that balance and make their garden the most productive.
Check out these tech resources to balance light and watering in a garden and experience photosynthesis with a deeper understanding:
Welcome back to the Tech Tips blog! As you may have noticed, we are really excited about the library's Teen Summer Reading program. Our theme this summer is 'Reading is Elemental,' and here at the blog we are going to be giving you a weekly dose of posts relating periodic elements and technology all summer long. Join us this week as we look at our first topic: Hydrogen and Helium and the genesis of all the Earth's energy.
The Genesis of Energy on the Sun
Constant complex atomic reactions (nuclear fusion reactions, for extra credit ) are taking place on our sun called Proton-Proton chain reactions. During these reactions, Hydrogen (H) atoms are combined together to create isotopes of Helium (He). See the image below (note: MeV denotes megaelectron volts, a measure of electric energy). The result generates electricity that radiates all the way to Earth. The resulting He isotopes undergo more atomic reactions that involve Beryllium and Lithium, further resulting in a release of energy. The sun's energy is radiated to Earth in the form of electro-magnetism.
In one form or another, the energy that you use comes from the sun's electro-magnetic ray. The food that you eat transforms the sun's energy during photosynthesis and uses it to create mass (e.g. glucose sugar in plants) storing energy that your body uses when you consume and digest your food. The stored energy is also passed to your body when you consume fish and animals that eat plants.
So What Does this Have to do with Technology?
The energy that you use to power devices like your phone, TV, and computer also originates in the sun. Depending upon where you live in the world, your main source of electrical power varies. The main sources of fuel that we use in KY are coal power and natural gas (to power our homes and charge battery powered devices) and petroleum-based gasoline (to power our transportation).
Coal and oil are fossilized versions of plant and animal matter that have undergone extreme heat and pressure for millions of years. Energy in the form of heat is generated when we burn those substances, and we use that to generate electrical energy (for more on this, stay tuned for the post on Copper). So when you use your computer to update your status or play a video game, the energy that is needed to power the device originates in the Hydrogen and Helium reactions on the sun.
Alternative Ways to Harness the Sun's Energy
Since there is a limited amount of fossil fuels left on Earth, scientists have been designing alternative ways to harvest energy from the sun's rays.
The most direct way is through solar-powered energy which can be divided into two categories. First, passive solar energy harnesses just the heat given off from the sun's rays and concentrates that energy to heat water or a greenhouse, etc. Second, scientists use photovoltaic panels to actively transform the energy in the sun's rays into electricity that can be used to power batteries.
Biofuels, like bio diesel are made from low-cost, mass produced sugary plant substances like sugar cane, corn and soy. The sun's energy is stored in the plant's sugars and is distilled into a purified ethanol and used to power machines and automobiles.
Onyx Photovoltaic Estimation is a cool, free app that uses your phone's screen to estimate the amount of power that a photovoltaic panel would generate at any location.
Teen Tech Tip of the Week #26: Explore the Night Sky
Monday, May 20, 2013, 10:06 AM - Tech Tips Posted by LFPL Teen Services
Welcome back to the blog after a bit of a break. We wanted to give you a little extra time for the past two topics, since they are rather difficult to digest. This week we are getting far out and are looking beyond our own planet into the sky and beyond.
Next week (June 1) marks the beginning of LFPL's summer reading for kids and teens and the themes for each are science-related: 'Build Your Brain' and 'Reading is Elemental' (respectively). For the entirety of summer reading we are going to look at a variety of science subjects on the teen blog.
For this post we are going as far out as we can possibly go: outer space! Below are several free resources to explore the entire universe:
Resources for Viewing the Night Sky
Google Earth (View>Explore>Sky, Mars, Moon) is a great place to start finding your place in our universe. Users can view pictures and find links to educational resources directly from a 3D map. Look at terrain features for Mars and take a virtual tour of the Apollo landing mission on the moon.
Stellarium will create a realistic view of the night sky in real time for any location on Earth. View constellations from all over the world including many different cultures.
Celestia is a 3D space travel simulator that allows you to travel through their extensive collection of astronomical bodies. View close ups of planets from our solar system and see the interactions of all objects at any point in the universe's history. Both NASA and the European Space Agency (ESA) utilize Celestia for outreach and public education.
WorldWide Telescope was developed by Microsoft and displays a 3D map of the universe taken from the Hubble telescope and nearly a dozen Earth-bound scopes. Download the Windows client or use the browser-based viewer.
Skychart (Cartes du Ciel) lets you turn your computer into a planetarium by mapping and labeling planets, stars and constellations. Overlap photographs to get a closer look at each object.
Aladin is a great tool for researchers that lets you browse through maps, images and dozens of databases of scientific research.
Louisville Astronomical Society - Since 1931, the LAS has been gazing and educating Louisville on our solar system and beyond. They offer monthly public star viewing at their Urban Astronomy Center located at E.P. Tom Saywer Park.