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Science News for Students

www.sciencenewsforstudents.org

Enjoy keeping up to date with the latest innovations and news stories in the STEM field? Science News for Students is the place for you!  Read articles and watch videos on almost every scientific topic you can think of. The site is full of science experiments, neat jobs you’ve probably never heard of, in-depth articles of current events, discoveries, and so much more.

What you can do: Head on over to the Science News for Students website to find a screenfull of articles and videos to explore. In the top menu, you can check out the many different sections the site has to offer by clicking on the Sections drop down menu.

  • In the Explainers page you can learn to understand some of the pivotal topics in the STEM fields, including how waves work, the pH scale, and allergies. Here you can also find information on relevant topics today like the coronavirus and global warming.
     
  • The Word of the Week page will show you this week’s chosen word of focus, with an article explaining the word and its applications in the STEM fields. The previous weeks’ words are also shown below. Some examples of words you might find here are polymer, spaghettification, and momentum.  
  • The Cool Jobs page will show you some of the most interesting STEM jobs found today, including some particularly interesting niche jobs.  
  • The Analyze This page will show articles that examine some of nature’s most intriguing characteristics and try to answer the question of why things are the way they are. For example, you may read about why beetles are certain colors or why insects migrate and much more. 

I encourage you to look over all of the sections that Science News for Students has to offer. There is so much content on this website that will help you develop your STEM knowledge. Remember, paying attention and staying informed on major science topics now will help you make smarter decisions in the future.

Privacy/For Parents: Science News for Kids is a fantastic way to keep students up-to-date on current STEM news. The articles are provided for free on their main website. There is also an email newsletter students can subscribe to that they can check to stay up to date. Science News for Kids is a subsidiary of Science News (ScienceNews.org), owned by the Society for Science. Here is a link to their cookie policy: https://www.societyforscience.org/cookie-policy/ 

Keywords: Magazine, science, science news, teachers and schools, students and parents, grades 3-5, grades 6-8, science, chemistry, earth science, life science, biology, physics, space, technology, nonprofit

 

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Before the Tesla Model 3 there was Nikola Tesla

It is funny how the history of technology often goes around full circle.  We went from centralized mainframes with terminals, to the PC which are decentralized, to the cloud computing which is centralized. With more people and businesses starting to use solar power in various forms, we are often forced to take DC voltage to convert it to AC voltage only to have our power adapters convert the power back to DC for use by our electronics.

AC/DC

The voltage from a standard wall jack is alternating current (AC), and the voltage from a battery is direct current (DC).  There are very few things that we use that are designed to use AC voltage directly without a conversion to DC.  The two main exceptions are incandescent bulbs, which can use either AC or DC power, and some electric motors. 

Electric motors can be designed to use AC directly or DC power directly, so some electric motors are AC, like the one that runs the fan in the heating and air conditioning unit in your house.  Other motors are designed to use DC current like the Tesla Model 3

So why are most power outlets AC if most things have to convert the power back to DC to use it? 

Back in the nineteenth century, when Thomas Edison invented the light bulb, his idea was to us DC power to power his light bulbs.  But there was a problem: Edison’s DC power system could not be transmitted over a few miles. This meant a power station would have to be built every few miles –a lot of power stations. 

Fortunately, an employee of Edison’s, Nikola Tesla, developed a way to use AC power to transmit

power cost effectively over many miles. Edison was against using AC power. Nikola Tesla quit after a disagreement with Edison and went on to work with George Westinghouse to provide electricity to households and businesses using AC power transmission lines and equipment. 

Tesla patented a number of inventions that had to do with AC power that are still being used today to produce and transmit electricity over longer distances. Tesla Motors, Inc. was named after Nikola Tesla.

Solar Power

Now we are starting to have a new problem. Solar panels generate DC electricity.  We often convert this to AC current only so we can plug in the power adapter of electronic devices that change it back to DC.

In a house powered entirely by solar power it would make more sense to use the DC power directly since the solar panels and the batteries that store their power in both use DC power, and converting between AC and DC or DC and AC is less efficient since you lose energy in the process.

How Solar Energy Works

Electric Today

Today, we have some long distance high voltage DC transmission lines but they are actually only cost efficient over much longer distances.

An overhead  cable run with HVDC would need to be between 600 and 800 kilometers to be cost efficient —  that is between 375 and 500 miles. 

Underwater and underground HVDC cables become cost efficient at about 30 miles or so.  So HVDC is often used  in long distance undersea cables. So even now, AC power is generally a better choice for the transmission distances we  need.

 

—Dean McIntyre, June 18, 2020

Learn More

Alternating Current (AC) vs. Direct Current

Sparkfun’s : Thunderstruck!

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Python

https://www.python.org

What is Python? Python is an interpreted object-oriented and high-level programming language. Python is a very popular and easy to use language, a favorite among many programmers. One of the greatest benefits of the Python language compared to others is that Python is open-sourced.  This means that anybody can contribute their work to the main Python libraries, packages of pre-made code that can be imported and used in Python. An example of this benefit would be a very efficient arrangement of code that sorts data faster than some other common method of sorting. 

How it works: In general, Python is manually installed onto the path of someone’s computer. One can download the latest version of Python from this website. A quick installation guide can be found here for Windows and here for Mac users. To make the most out of Python, integrated development environments (IDEs) are used to help format, troubleshoot and run Python code. Most IDEs are like more advanced versions of the command prompt/line, they are more visually intuitive and provide the user with troubleshooting and formatting tools. You can use some IDEs to build computer/web applications that run on Python code. 

For parents/privacy: Python can be installed onto your computer from the official Python website. Python is a very popular and secure programming language that’s great for beginners to learn on. Here is the Python code of conduct, and here are Python’s legal notices.

Resources: Interested in Python? Check out these resources to learn more and see some real-world applications!

 

 

Watch Reza Tasooji explain the basics of the Python language and some basic programming terms.

Watch this clip showing some of 2018’s best Python projects (some of them are crazy!)

Also watch Reza give an in depth tutorial on how to install Python onto your Windows operating system and explain why it’s important to create virtual python environments.

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Tech on Tap Online Event

 

No Camp? No Problem! 
STEM Ideas for Family Summer Fun

Thursday, June 18, 2020
4:00pm – 5:00pm

Registration

With kids at home this summer, you need a game plan. Join two Virginia Tech STEM education specialists, Jim Egenrieder and Erika Bonnett to learn about outdoor and indoor activities in which families can have so much fun they won’t realize how much they’re learning.

About Tech On Tap
Learning happens everywhere. Tech on Tap is a regular community speaker series that informs, educates, and raises questions about the impact of new technologies on society, equity, and policy. Topics include the types of issues and problems Virginia Tech’s Innovation Campus in Potomac Yard will explore.

 

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Google Colab

colab.research.google.com

Google’s Colaboratory, or “Colab” for short, is a free online resource used for sharing code, documentation, and visualized data. Google Colab runs code using Jupyter Notebook, an open-source web app used to create and share documents that can run live code and visualizations. Colab itself runs on a virtual linux operating system. The programming language that can be run live in Google Colab is Python, while Markdown code can be used to format and organize the Colab documents. Google Colab is a very engaging and interactive way to run code, examine data and share ideas on the web.

What you’ll do there:  With Colab you can write and execute Python in your browser. Students in STEM+ Data Analytics course will learn to use Colab as a part of their assignments. One of Colab’s best features is its ability to run live code, which makes teaching and learning Python a lot more engaging and intuitive. In addition to learning Python, students will also learn how to format their documents by using the Markdown language. With these two tools, students will be able to use Python to visualize and analyze data in conjunction with Markdown to clearly format and organize it. 

For parents/privacy:  Students will need a Google account to use Google Colab, as Colab is an app made by Google. Google accounts are free to create and require some basic information, such as first and last name, a username and a password. Here is Google’s privacy policy.

Additional resources: There is a lot to learn about Google Colab, Markdown, and Python – most of which is not covered in the STEM+ Data Analytics course. Here are a few safe additional resources for your convenience:

 

 

 
 

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Roanoke Higher Education Center

Main Link:  www.education.edu 

STEM+ by Commonwealth Learning Systems lab is located in Suite 813

108 North Jefferson Street
RoanokeVirginia 24016

(540) 767-6161 

DIRECTIONS & PARKING

 

The Roanoke Higher Education Center (RHEC) in historic downtown Roanoke develops partnerships and maintains a state-of-the-art facility that provides citizens of the Roanoke region access to training, certifications, and degrees. 

  • undergraduate and graduate programs from member universities
  • testing center
  • customized training
  • education fairs
  • meetings and conferences
 
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Faster Than the Speed of Sound

When I was a kid, I use to turn the light off in a room and stand as alert as possible in the dark without blinking. Then, I would turn the light switch on and see if I could actually perceive the light moving from the light bulb across the room and filling the room with light.

Spoiler alert: I could not.  If the sun were a light bulb, it would take about 8 minutes for light to reach earth if it were off and we turned it on. It takes over 4 years for the light from the next nearest star to earth to reach the earth.

I would imagine a light going on a light year away and it traveling though the darkness and lighting things up along its way. There is no way to see that — it is something someone can only imagine, because to see it, you would have to slow down time a million times. Plus space is empty and you cannot see light traveling through it unless it lights something up like a wall, or a planet, or asteroids or particles of dust.

As fascinated as I was with how fast light moved, I was even more interested in the speed that sound moved, because that was something that I could perceive under certain circumstances. I was astounded to learn that the speed of sound actually changed because of atmospheric conditions and elevation. It is not a constant like the speed of light. If you are trying to break the sound barrier in a plane or a car, the speed you break the sound barrier will be slightly different depending on the atmosphere, the temperature, and the weather. 

You may have noticed during a thunderstorm that sometimes there is time between a lightning flash and the sound of thunder. This is because light travels much faster than sound.  In fact, if you see lightning and start timing until the thunder, you can estimate the distance the lightning is from you, and whether it is getting closer or moving away.  If it is getting closer, the light and sound will be closer together.  If it is getting farther away the light and the sound will be spread farther apart in time. 

It takes about 5 seconds for sound to travel one mile. Light travels a mile in about 5 microseconds.  Microseconds are a millionth of a second which means light travels about a million times faster than sound. If the time between lightning and thunder is  around one second, then the lightning is about a fifth of a mile away (352 yards or 3.5 football fields), or less than a quarter of a mile away.  If the light and sound are less than a second apart, the lightning is very close.  A few times I have been in really bad thunderstorms, and when I realized the light and sound was getting longer and longer apart, I was relieved, because I knew the storm was travelling away from me.

Sonar

When we yell across a  canyon, and we hear our echo, the delay between when we yell and our echo returns is the time it takes for our voice to carry to the rock wall on the other side of the canyon and bounce off and travel back.  Similarly, in a large empty room we will hear echoes of various delays depending on how big the room is. 

Sometimes the echo is less noticeable depending on how reflective the surfaces are and how much the sound bounces around.  In fact, in a small bathroom with tile walks you will notice a lot of echo, because the sound is bouncing around multiple times off the walls. 

This is also how bats use sonar to navigate through dark caves.  They squeak and their voice bounces off the cave wall and they can tell how close they are to the walls by the sound or the delay in the return of the echo.  No, bats are not supercomputers or digital tape measurers.  They are just tuned into the differences in sound just like you can tell the difference of the sound of a coin dropping on a hard floor a few feet from you, and one that is dropped on the same floor on the other side of the room. Bats just have more sensitive hearing and their brains are more aware of subtle differences in the sound. 

Sonar used in submarines, and in underwater research to map the floor of the ocean use the same principle, and radar and ground-penetrating radar uses a similar process except it uses radio waves instead sound to bounce off objects to either detect or map things that we cannot easily see like the bottom of the ocean or if there is something buried or a cave underground.

Sound and Temperature

If you go to weather.gov , there is a calculator that will give you the speed of sound based on temperature. Temperature is  the primary factor that affects the speed of sound in the Earth’s atmosphere.

Concerts and the Speed of Sound

In a large auditorium, the distance from the stage to a seat in the very farthest point in the building is probably less than a quarter mile. This means the time it takes for sound to travel from one end to another is going to be less than a second.  There will be a fraction of a fraction of a second delay for the sound to travel from one end of the auditorium to the other. 

 In a very large auditorium or stadium, however, there can be problems. If you have all the speakers up on the stage, the sound would have to be so loud to reach people in the back that it would be too loud for the people close to the stage.  This is because sound falls off the farther distance it has to travel.

In order to compensate, musicians put additional speakers in a large auditorium or stadium at various intervals along the sides.  This can cause a problem, too, if the venue is large enough, because the signal going through the speaker wire is going at the speed of light. The speakers in the back will sound at the same time the ones at the front, but the sound coming from the front of the house will follow to the back at the speed of sound. It will be fraction of a second later, causing a noticeable delay or echo.

To compensate for this, larger auditoriums and stadiums will put a delay on the speakers that are farther back in the house, so that they are in synch with the sound coming from the speakers on the stage and closer to the front of the house.

Echo Chambers in Music Recording

Musicians, rock groups, and singers often use what are called modulation effects such as reverb, echo, and delay to create depth or texture to a song, but these effects were originally created to emulate the sound of an echo in a large room or auditorium. In fact, in Abbey Road Studios where the Beatles, the Foo Fighters, Miley Cyrus, Queen, the Red Hot Chili Peppers, Kanye West, and many others have recorded music, they have special rooms, called echo chambers, that they sometimes use to create various echo effects using the actual accoustic properties of the room instead of an electronic filter or effect. 

If that does not blow your mind, there are manufacturers of electronic and computer generated effects that have gone to a great deal of trouble and effort to emulate the sound of the echo chambers at Abbey Road Studios. I guess art and science really do mimic each other.

—Dean McIntyre, June 5, 2020

 

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**CLS COURSES

Drones – Learn to Fly

Learn to Fly Drones is a new online, interactive class that introduces drone basics to students of all ages —– before they send drone equipment into the air.

Designed and led by Virginia Tech instructors, the course reviews drone basics, explains the steps to earning a Drone license, and allows students to practice navigating drones in simulation BEFORE taking equipment aloft.  

How it Works

Learn to Fly Drones! will be offered Summer 2020. 

Students login to a virtual classroom from the STEM+ website. The virtual classroom outlines the weekly schedule of activities, videos, and assignments. 

The schedule includes live online Zoom sessions  with the course instructor. These sessions anchor the course for students. and provide interaction and encouragement.  Live online sessions may include class demos, Q&As, or general discussions about data analytics in our current world. 

STEM+ may be allowed to offer optional in-person afternoon labs at the Roanoke Higher Education Center (pending state guidelines and restrictions). When we have more information, we will share it with the registered students.

Explore Data Analytics is offered through STEM+ by Commonwealth Systems.

Contact Us

Questions? Would you like to register? Let us know. Fill out the form and we will get back to you ASAP

Contact Us

Level

 

Dates

TBA
 live online sessions with instructor

Fee

TBA

Limited scholarships are available. 

Instructor

Dean McIntyre

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The Tone Chasers

Amp Technology: How Sometimes the New Stuff Struggles To Be As Good As the Old Stuff 

It’s always a Catch-22 situation. They hate you if you’re the same, and they hate you if you’re different.

 

— Eddie Van Halen

Great Balls of Fire

In the 1950s, when the electric guitar and rock and roll were first taking off, Jerry Lee Lewis was told he should give up the piano and play guitar.  The guitar was latest thing, guitar players move around more, and the guitar was more exciting. 

Jerry Lee Lewis showed them the piano could be exciting. When he played Great Balls of Fire on the piano, he would stand up and kick the piano bench away and start dancing and rocking as he played keyboard.

It is still hard to beat Chuck Berry’s duck walk, Jimi Hendrix setting his guitar on fire, Pete Townsend smashing his guitar on stage, or T-bone Walker playing his guitar behind his head, but Jerry Lee Lewis managed to shake things up at the time.

Eruption

By the late 1970s things had changed. Keyboards and synthesizer technology seemed to mimic any instrument, as well as produce new and different and modern sounds. The same type of people who told Jerry Lee Lewis the piano was dead now said the electric guitar was dead.

In 1978, Van Halen released an album with the short instrumental track called Eruption.

In that track, Eddie Van Halen, played the guitar and made it sound like no one else had ever played it. He tapped the strings with his fingers in parts instead of just picking, he used the whammy bar to dive bomb notes, and he used amp distortion in a way that made the notes sing and do impossible things.  Eddie Halen has said many times that he considers himself a tone chaser.  In fact, the story behind music technology is often a back and forth between the technology chasing the tone and the tone chasing the technology.

Fender & Guitar Amp Technology

In 1938 Leo Fender opened a radio repair shop. Leo Fender would go on develop a number of inventions and designs related to amplifiers and electric guitars. Two of the three most common electric guitar body designs today are based on designs by Fender.

At that time, vacuum tubes were the cutting edge of electronic technology.  Fender designed a guitar amp using vacuum tubes. It was a challenge because tube amps, particularly earlier tube amps, use a technology where hum and distortion can be a problem. The guitar pickups added noise, feedback. and hum. Fender designed an amp that worked to prevent this, creating amps that put out some of the best clean, undistorted tones on a guitar.

Now, when you want to design an amplifier, the two things you want to do is remove hum and distortion, particularly if you are using the amplifier to play back sound recordings. In general, a musician does not want the amplifier changing or distorting the sound of the recording.

Guitarists are not radio repair techs or sound engineers. Most of them just twist the dials on an amp until it sounds good, particularly back in the day.  If they were sound engineers, they would explain that a guitar amp is actually two amps: a preamp that boosts the signal of the guitar input from the pickup to an ideal level for the second amp, the power amp, to amplify the signal for the speaker of the amp. 

If the input level is too low, the power amp needs to be turned up louder to get the same level of amplification. The louder the input level the less hard the power amplifier has to work.  The reason it is so important for an amplifier not to have to work so hard is that the amplifier not only amplifies the sound, it amplifies the noise and hum of an input as well.  Also, the louder the amplifier, the more distorted it tends to get, particularly with tube amps.

Different guitar pickups have different signal levels. By adjusting the preamp you can adjust the input level to the optimal level.  Both guitar pickups and microphones use preamps to adjust their input level or their level of sensitivity.  There is a knob on a guitar amp called “gain” which controls the preamp volume and then a knob marked “volume” that controls the power amp level. Gain is equivalent to the recording level on a sound recorder.

You might think that that was a lot of explanation when you could just turn the knobs around on an amp until it sounded ok.  This is what most guitar players of the 1950s did. Crank up the gain on an amp too high, you get distortion. The power amp amplifies that distortion so as you turn up the power amp more, it amplifies the distortion more and adds it own distortion to the distortion. This means by fiddling with the two knobs you can go from a very clean signal to a very distorted signal.  

Transistors & Solid-state Electronics

While all this was going on, the transistor was invented at Bell Labs in 1947.  The transistor was invented as a replacement for the vacuum tube, and is considered to the beginning of solid-state electronics. When we use the terms semiconductor or chip, we are talking about solid-state electronics. Because almost all electronics are solid-state now, we do not use the term as much.  We might refer to something as having tubes in it now, but back when vacuum tubes where the main technology, people referred to electronics without tubes as solid-state, because that was the new and unusual thing.

Solid-state guitar amps are great at creating clean, undistorted tones. The problem is that the “disadvantages” of the vacuum tubes produce the great distorted tones that cannot be fully reproduced with solid-state or digital technology. The distortion on tube amps is quirky and responds to how a guitarist plays the guitar in ways that are hard to or impossible to entirely reproduce in a solid-state amp.

Leo Fender and others spent the first part of amplifier history chasing the perfect clean tone for an amplifier with technology that wanted to distort the sound. Meanwhile, guitar players started experimenting with distorted sound from the amplifiers, because they liked what they heard. They realized that some of the best tones on an electric guitar are distorted to some degree even if it is just slightly. 

Eddie Van Halen

During the 1960s and 1970s, vacuum tube technology was being replaced by solid-state technology. While Eddie Van Halen is often credited with saving the electric guitar in rock music, no one seems to mention that he also may have had a part in saving tube technology from the junk heap as well.  You see, the main place where vacuum tubes are still used today is in guitar amps.

Fast forward back to 1978 and Eddie Van Halen was using a whammy bar of a design created by Leo Fender along with the distortion from a tube amp and finger tapping that was being used by Emmett Chapman, inventor of the Chapman Stick, in the late 1960s.  Eddie Van Halen’s big moment when he saved the electric guitar was forty years in the making and partially based on what was once considered a weakness in the technology.

What is the Difference?

To get an idea of the difference between tube and solid-state guitar amps, you can go to a flooring store and look at the different types of wood and artificial wood flooring. At one end you have real wood flooring — solid wood that has all the benefits and drawbacks of real wood. Next you have various engineered wood flooring which might be real wood on the top, but underneath is made of composite material or a cheaper type of wood, etc.  Finally, you have laminate flooring made of manufactured materials. 

The best laminate flooring is often hard to tell from real wood, so many people would not notice the difference at first. However, if you stand and look at a laminate floor for a while, you will start to notice that some planks have the exact same wood grain. This is because manufacturers make only a half dozen plank variations. 

In a real wood floor, each plank is unique. The same is true of tube amps and solid-state amps and digital modelling amps. Digital modelling amps may use computer technology to try to reproduce tube distortion, but you tend to end up with the tonal equivalent of a laminate wood floor.

The digital world is clean and precise, but it is also pixelated and predictable.  The analog world is warm, fuzzy, less predictable and has smooth slopes instead of stair stepped ones and zeros.  This is one reason that you might hear of some electronic device that uses an analog solid-state circuit instead of a purely digital one.

Sometimes we discover an old technology is better for a particular application and other times we get ideas from old technologies on how to implement new technologies.

Korg, the synthesizer company, developed an electronic component they call a NuTube.  A NuTube is basically a solid-state tube, a semiconductor that is designed to behave like a vacuum tube.

The jury is still out on whether a NuTube is as good as a vacuum tube for a guitar amp, but the results the NuTube have gotten so far look promising and seems to be one of the better attempts at a way to emulate a vacuum tube amp with solid-state technology.

–Dean McIntyre, May 28, 2020