Teen Tech Tip #32: QR Marks the Spot 
Welcome back to the blog. Thanks for joining us for the Library's Teen Summer Reading and our summer series here at the blog. We had so much fun experimenting with science!

Now that summer has moved into the school year, we are going to continue with our original mission of delivering posts revolving around technology. For our first week back, we are going to look a fun project that you can do on your own for a school project or fun with your friends and family: making a QR code scavenger hunt!

You may have joined us for a hunt this summer at the Library's Teen Survivor Night and Animecon X.



A Little QR History


First developed by a subsidiary of Toyota in the mid-1990s, QR codes (short for Quick Response Code) were initially designed to track vehicle parts during manufacturing (much like a grocery scanner tracks inventory from UPC codes). Due to the high amount of data that can be stored, QR codes were adopted for other applications, most notably the advertising industry. QR codes can hold a URL address that, when scanned with a smartphone, takes the user directly to a website. This makes accessing a site much quicker that manually typing the site address and utilizing a search engine.

There are multiple free apps that you can use to scan and retrieve information from QR codes. To find one, search your App marketplace, any of the free apps will work just fine.

Since QR codes can hold large types of data (like really long URL addresses), they are the perfect tool for creating a digital scavenger hunt.

What do QR Codes have to do with Scavenger Hunts, exactly?


Since QR's can hold data types, like URL addresses, you can set up a website that holds information leading a seeker toward clues. Try scanning or clicking the code at the top of the page .

When the user scans a QR, they are taken to a web page that holds the information that will lead them to the next code. When they scan the next code, they will be taken to another webpage that has all the information for finding another clue until they reach the end.

Making Your own Scavenger Hunt


To make your own scavenger hunt, you'll first need to make your own website with as many pages as you have clues. For more information on making your own site, click here. (We used Weebly.com to quickly create our own free site)

Next, transform all the URL address for each page of your site into a QR code. We used goo.gl URL shortener. Just click details under the shortened URL after verifying the captcha. You will be able to save the QR image for the hunt.

Print and hide the QR's within the parameters of the hunt boundaries, and edit the pages to give clues to the next code. Be sure to hide the pages on the home page when editing your site, or else the player can simply click the link to the last clue and find the prize.

A Hunt of Epic Proportions


If you can't get enough of scavenger hunts, give Munzee a shot. This combines QR hunts with GPS technology to lead you to hides in 50 different countries. This does require you to have an additional device with a GPS receiver, but most smartphones have that.

Awesome Treasure Hunt Reads

If you enjoy seeking treasure or a good scavenger hunt, then be sure to check out these great books from your Library. Special thanks to Heather at the St. Matthews Library and Lindsay at Southwest for the reading recommendations!

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Homework Help 
School is back in session, and with the new year comes reading, homework, projects, and other important assignments. Regardless of your grade, whether youíre beginning sixth grade or working on graduating high school, there are numerous tools to aide with homework or help you brush up on any academic subjects.

Today we will discuss the information that you can access through the Libraryís Research Tools and Jefferson County Public School's Practice Your Skills. There are different Practice Your Skills sections for each level of education Elementary, Middle, and High once you click on the Students link from the JCPS website.

By having a library card, you can access a variety of databases and research sources from the Library's website. Anything from Arts & Entertainment to Test Preparation is readily awaiting your use.

(Donít forget High School students with ACT test coming up the study guides and practice tests)

For the JCPS site, you do not need anything but a computer with internet access. Narrow your lessons by grade and content area. Some of the homework help tools may be cut-and-dry lessons, while some may have a game to go along with a lesson, like Math Baseball.

-Micah Followay, Shively-Newman Branch

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Teen Tech Tip of the Week #30: Sodium and Chloride Make Salt Elemental 
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.


Further Reading


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.

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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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