Teen Tech Tip of the Week #29: Nitrogen Makes Growth Elemental  
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 Conversion

  • 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.

Human Contribution


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.

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Teen Tech Tip of the Week #28: Carbon, Hydrogen, and Oxygen make Photosynthesis Elemental  
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:
Join us next week as we look a little closer how Nitrogen plays an essential role in plant growth.

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Teen Tech Tip of the Week #27: Hydrogen and Helium make Energy Elemental 
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.

Earth's Energy


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.

There is a diverse world of alternative energy that is constantly changing due to technological improvements. Here's a cool app to keep you up to date from Renewable Energy World:

(Montage of alternative sources of energy: wind, hydropower, and photovoltaic cells)

Here's an extra credit question for your Teen Summer Reading activity point: how are wind-powered and geothermal electricity also forms of the Sun's energy?

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Teen Tech Tip of the Week #26: Explore the Night Sky  
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.

(Source: NASA)

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.

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Teen Tech Tip of the Week #25: Computer Programming (Pt. II): Computer and Mobile App Development 
Last week we started to break the surface of computer coding a bit, and we introduced you to some free sites that allow you to learn the basics.

Some of you may be wondering, 'so how do the pros do it?' This week we will explore that question and give you the tools that you need to make and distribute your own apps.

Workflow Basics


Now that you have had a bit of time to key around with different programming languages, let's talk about what to do with the skills that you have begun to develop. We will discuss putting your skills to work through computer and mobile app development, but keep in mind that your skills are not limited only to building apps.

Apps are typically self-contained programs that perform a series of tasks related to the same overall function. Apps all have some sort of graphical user interface (GUI)--which is a fancy way of saying the buttons on the screen that the user pushes and the content being displayed.

Operating systems for devices have evolved to include easy access to a marketplace (Apple App Store, Google Play, and the growing Windows Store) rich with free and low-cost apps.

There is currently quite a bit of free software available designed to create apps for a variety of marketplaces, and the software is aimed at professional developers and hobbyists alike.

Though development varies across platforms, the basic concepts are all the same. Each platform has a specific set of tools called a software development kit (SDK) for creating apps. Those tools usually include the following: code editor, interface builder, frameworks (prefab code libraries), code debugger, a simulator that gives you a live test of your app, and some way of measuring how your app performs on a specific device.

To integrate all the tools, programmers utilize an integrated development environment (IDE). It may be helpful to think of the SDK as the tools necessary for building an app, and the IDE functions like the workbench keeping all the tools together and at close reach.

Many apps also require an application programming interface (API) to communicate to an operating system, a database, or some other piece(s) of software.

Below is a list of resources broken down into three popular development platforms Android, iOS, and Windows. Getting started can be a bit tricky, so I have included getting started resources and tutorials. The image above features an infographic detailing the general workflow for building an app. In the tutorials below, you will find similar charts more specific to your needs.

Android


MIT App Inventor - this browser-based IDE runs on Java and is a great to start. Tutorials found here.
Eclipse IDE and Android SDK (Bundle) - a more robust IDE from Eclipse
Building Your First App Tutorial - get started with installing and developing with this tutorial
Resources

iOS


iOS Developer Center - sign up and start making iPad, iPod and Mac apps
XCode - Apple's IDE and programs are written in Objective-C
Getting Started
ManiacDev - a one-stop for new and professional developers alike with libraries and tutorials

Windows


Visual Basic Express - Microsoft's IDE and apps are typically written in C# or C++
SQL Server Express - Microsoft provides you with a free database engine to power your apps
C# Tutorials - to get you started making apps with VS
MDSN - Microsoft's developer network with all the resources you need


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