beanz Magazine August 2017

Kids, Code, and Computer Science

n a s ’ t I ! a m g i n E The World of Secret Codes, and How You Can Create Your Own Learning Robotics with Lego EV3 Who Knew Turtles Could Draw?

August 2017

$6.00 USD

Don’t Feed the Trolls!

beanz magazine August 2017 : Volume 5 Issue 1 Issue 31 (online) & 16 (print) ISSN: 2573-3966 (online) ISSN: 2573-3958 (print) beanz Magazine© is published bimonthly, six times a year, online at https://beanzmag.com and in print.

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Published by Owl Hill Media, LLC 378 Eastwood Rd, Woodmere, NY 11598 Email: hello@beanzmag.com Phone: (646) 553-3390

Welcome!

You’re reading a magazine both old and new. We’ve published since August 2013 (online) and February 2015 (print) but this issue marks a really important milestone for the magazine.

And, no, it’s not going from the world’s longest magazine title— Kids, Code, and Computer Science Magazine—to maybe the world’s shortest—beanz.

The real milestone? We have enough readers to hire a real-life magazine designer to magically turn the fun stuff we write into an amazing experience to read and hold in your hands.

When the magazine started, I wanted an excuse to research and write about computer science and programming. Writing for younger humans is a bonus, a great way to force myself to write clearly and focus on the amusing and amazing bits. We’ve since added writers and now a designer, Kelley.

Like me, Kelley is amused by small things like birds that pop up different places. And fonts. And colors. She also likes to learn, as I do and assume you do.

And, if you’re wondering, what do beanz have to do with tech?

In software programming, beans are small units of code mixed together to create applications, the way words and images are mixed together to create articles and a magazine.

Hopefully, the new magazine design will become an experience you enjoy, a neat way to explore often hidden fun parts of the world.

POSTMASTER: Send address changes to Owl Hill Media, LLC, 378 Eastwood Rd, Woodmere, NY 11598.

Periodicals postage paid at Woodmere, NY and other mailing offices Copyright Owl Hill Media, LLC with all rights reserved except as noted. Flickr images are copyright their creators, as noted with each story both online and in print.

Publisher/Editor/Webmaster: Tim Slavin Staff Writers: Simon Batt, Patricia Foster, Charles Hanks, Clarissa Littler, Jennifer Newell, Les Pounder, Paul Seal, Erin Winnick, Tim Slavin Contributors: David Dodge, Jay Silver, Jeremy Kubica, Colleen Graves, Daniel Fenjves, Ali Hagen, Jordan Holmdahl, Emeline Swanson, Jenn Choi, Jean-Francois Nguyen, Madeleine Slavin Copy Editor: Madeleine Slavin Art Director: Kelley Lanuto COVER IMAGE: MIKE, FLICKR

Tim Slavin Publisher beanz Magazine beanz magazine (as Kids, Code, and Computer Science magazine, our earlier title) is a winner of Parents’ Choice, Tillywig,

Our Mission

and Academics’ Choice awards: https://beanzmag.com/awards

beanz magazine is a bi-monthly online and print magazine about learning to code, computer science, and how we use technology in our daily lives.

The magazine includes hard-to-find information, for example, a list of 40+ programming languages for education, coding schools, summer tech camps, and more.

While the magazine is written to help kids ages 8 and older learn about programming and computer science, many readers and subscribers are parents, teachers, and librarians who use the articles to learn alongside their young kids, students, or library patrons. The magazine strives to provide easy to understand how-to information, with a bit of quirky fun. Subscribers support the magazine. There is no advertising to distract readers.

The magazine explores these topics: Basics of programming and where to learn more, Problem solving and collaboration, Mathematical foundations of computing and computer science, Computational thinking, Recognizing and selecting computer devices, Community, global, and ethical impacts of technology.

contents

advanced

beginner

intermediate

August 2017 Cover Story

2

Secret Codes Create a Basic Cipher

4 Concepts: On Sorting 6 10 11 12 14

Robotics Cover Story Lego EV3 Make It Your First Machine Coding Cover Story Who Knew Turtles Could Draw?

Puzzles The Birthday Paradox Scratch Getting Started

tidbitz 22 23 23 23 24 24 25 25

15 16 18 20 21

You Can’t Hear This Say What?

New Coders Speak Out Think Your Way Out of a Paper Bag Wonder Women No Bones About It Watch This Space Plastic Rocket Men

Minecraft Getting Started Coding: Chain of Command, Command of Language Circuits What’s a micro:bit? b safe online Cover Story Don’t Feed the Trolls!

Show and Tell Schattenbilder

26

Offbeat

The Fascinating History of…

Barbed Wire?

28

Parent-Teacher Corner Girls and Computers

BY SIMON BATT

Secret Codes

2

o

a e t a e r r e C h p i C c i s a B PHOTOS: THIS PAGE BY MIKE, FLICKR, NEXT PAGE (TOP)

BY PARAMETER_BOND, FLICKR, NEXT PAGE (BOTTOM) BY ANDY ARMSTRONG, FLICKR

An Enigma Cipher Machine

Have you always wanted to create your own secret code? Ciphers (secret codes) are fun to learn about and create.

A lot of computing’s early successes were in the field of codebreaking.

During World War II, the Allies had to find a way to crack the German cipher to understand what they were planning to do.

A lot of mathematicians tried, including Alan Turing, who would go on to become a founder of modern computing. Powerful computers such as the Bombe were built solely for the purpose of trying to crack the code.

Let’s take a look at a very simple cipher you can create in a few minutes; a Simple Substitution code. The entire code is built around substituting letters for other letters. Begin by creating an alternate alphabet. This is done by creating a table two cells high and 26 cells wide. In the top row, write out the alphabet from A to Z. Then, in the bottom row, you ‘assign’ each letter of the alphabet with a different, unique letter. For example, if you write down A, B, C and D in the top row, you can then write S, E, Z, and R underneath each of those letters in the bottom row. Make sure none of the letters share a substitution.

A S

B E

C Z

D R

When you complete this from A-Z, you’ll have a normal alphabet above a scrambled one. This is your cipher! Spell words using your scrambled alphabet instead of the normal one. Give the solution table you created to anyone you want to understand the code.

So, let’s give simple substitution a shot! Let’s say you and a friend want to meet in secret somewhere, so you decide to use a cipher.

One day, your friend sends you the following cipher alphabet: A B C D E

F G H

I

J K

L M N O P Q R S

X O Y Q M C G R U K S W A

F

T U V W X Y Z

L N T H D J

P Z

I

B E V

Later, he sends this message: “wmj’d ammj fmxh jrm djlhm oe jrm nxhs!” Can you read it?

If you wanted to respond with this: “Okay! Let’s meet there after school, don’t be late!”, how would you write it using the cipher?

Unfortunately, Simple Substitution isn’t a very strong cipher. It’s easy to figure it out. If you see a letter on its own in a substitution cipher, there’s only really two solutions it could be: an A or an I. You can then can apply that knowledge to the rest of the cipher. For instance, if you see an X by itself, that X will be either an A or an I. Then if you see ‘xn’ in the sentence, it might be ‘an’, ‘if’, ‘is’, etc.

If the person creating the cipher kept punctuation within their code, you’ll be able to deduce letters that way. If you had a cipher with “gtsg’p” in it, there’s a good chance the P might be an S (as in “that’s”). Also, watch how often letters appear. If a specific letter ends up showing rarely, you can probably deduce it’s one of the rarer letters in the alphabet, such as X or Z. When making your own cipher, how can you avoid these kinds of flaws?

Perhaps you can remove the grammar entirely and write the code so people can still understand it without the need for punctuation. Maybe you can also tackle short word length by combining them together. Have fun experimenting with ciphers! b To learn more, check out the links on the back cover of this issue.

3

as W o Wh g? n i r u T Alan The story of Alan Turing is an interesting one, as it shows that not every war hero is a soldier! Born on June 23, 1912 in London, he would go on to help crack the Enigma Code the Germans used in World War II. It’s estimated that his efforts shortened the war by two years and saved millions of lives. Turing would then go on to establish the early foundations of the modern computer. These days, the Turing Award is given to those who contribute significantly to computer science. The Turing Test was invented to see if an AI speaking via text can be distinguished from a real human being.

Closeup of a reconstructed Bombe computer

Have you ever put books in alphabetical order? What do you think the best method of alphabetizing would be? Would you leave the books on the shelf and just move them one a time?

Would you first put them in stacks of A’s, B’s, etc. and then sort the stacks? Maybe you’d start by

BY CLARISSA LITTLER

On Sorting

Concepts

4

picking a book and first dividing the shelf into all the books that would come before it and all the books that would come after it.

Alphabetizing is an example of a type of sorting. Sorting is when you take a number of things and put them in order. You could be sorting by date and time, by name, by author name, by size, or any notion of ordering that says “this should come before that”.

Sorting is a deeply explored topic in computer science.

Computer scientists care about sorting for the same reason a bookstore cares about

alphabetizing its shelves: it makes finding things much easier.

One of the simplest and most intuitive ways of sorting is called the bubble sort. You may have discovered this just by trying to put things in order!

It works like this: start from the left hand side of the list of items, until you reach the end for each element, compare it to the element to its right. If the element on the left is bigger, swap them. If the element to the right is bigger, leave them alone. Repeat with all the elements until the list is in order.

Here is a bubble sort shown as a Python algorithm that sorts a list of numbers: def bubble(lst,verbose=False): n = len(lst) - 1 isSorted = False while not isSorted:

isSorted = True

for i in range(0,n):

if lst[i] > lst[i+1]: if verbose:

print(“Swapping: “ + str(lst[i]) + “ and “ + str(lst[i+1]))

tmp = lst[i+1]

lst[i+1] = lst[i]

lst[i] = tmp

isSorted = False return lst Here’s an example of how a bubble sort works. Start with the list [5,2,3,9,9,4].

We start on the left and see that 5 is greater than 2, so we swap them and the list becomes [2,5,3,9,9,4].

In the next round we can see that 5 is greater than 3, so we swap again and get [2,3,5,9,9,4].

The third time through, 5 isn’t greater than 9, so the list stays the same [2,3,5,9,9,4].

Next pass through: since 9 isn’t greater than 9, the list stays the same again [2,3,5,9,9,4].

After that since 9 is greater than 4 we do another swap and reach the end of the list [2,3,5,9,4,9].

We’re not sorted yet, because of that 4, so

we start the process over again.

The next few steps leave the list unchanged until we compare 9 and 4 where we swap again [2,3,5,4,9,9].

Since 9 isn’t greater than 9 we again reach the end of the list and start back at the beginning. In the next round nothing changes until we swap the 5 and 4, and nothing changes again after that, leaving us with [2,3,4,5,9,9].

Once we reach the end of the list in this third round of swapping, we can make one last pass through and discover that it’s in order!

You can try running the Python code above and it’ll give you the same result. If you pass in True as a second argument to the code you’ll see what swaps are being made in the sort.

This isn’t a very good sorting algorithm, though, because sometimes you have to make many passes through the list to move things into the right position.

If you had a 0 at the end of the list instead of a 4 in our example you would have to have run through the entire list two more times to get the single 0 in the right spot. This means you’d have to make about 30 comparisons of elements just to sort a list of six elements. If you had a list of 1000 numbers and the smallest number was to the far right of the list,

you’d end up having to do almost a million comparisons to sort the list.

For a list 100,000 numbers long, you could end up doing about 10 trillion comparisons to sort the list. Even on a fast computer that means you’d be waiting at least 15 minutes just for a list to be sorted.

Imagine trying to sort a “bookshelf” as big as Amazon’s database of books, which could take at least 10000 times longer still. That’s about 100 days in the worst case!

Thankfully, computer scientists have come up with many other ways of sorting: quick sort, merge sort, bucket or radix sort. These methods divide the problem of sorting into smaller pieces than just “let’s compare every number”.

A bucket or radix sort splits the list up by something less precise first, like the starting letter for alphabetizing books, or by the digit in the 100s place if all your numbers are less than 1000. Once you’ve created these coarsegrained buckets, you can use whatever kind of sorting you want inside the small buckets. Even a bubble sort!

In a merge sort you split the list into very tiny pieces and then combine them, or merge them, so that they’re in order.

Finally, in quick sort you pick an item, then split the list into two parts: the things bigger than the item you picked and the things smaller. You then sort the two halves by doing the quick sort on each of those pieces.

If you’re interested in learning more about sorting algorithms, look at the back cover of this magazine for links to code and explanations. b

DENNIS JARVIS, FLICKR

5

Robotics

6

o g e L 3 V E

BY JENNIFER NEWELL

With an EV3 Robotics Set, You Can Build All Kinds of Robots What Does Robot Mean?

Most of us know what a robot is, but many people do not know what the word means. It comes from the Czech word “robota”, meaning forced labor! Therefore, a robot is a machine that we can build that will do labor, or work, for us.

Building a robot single-handedly, completely from scratch, requires learning mechanics, electronics, and programming. Luckily, Lego has given us a great place to start by creating a robotics kit called EV3. With a Lego EV3 set, we can build robots of all sorts that can do all kinds of work: lifting, throwing, flapping, rolling, and much more.

What’s in the Box?

It depends on which edition you buy. In the Home Edition, you’ll find approximately 600 building elements. Many of these are Lego pieces that you can find in a Lego technic set. They include axles, gears, beams, and connectors to name a few. Additionally, there is an EV3 Brick (the programmable “brains” of the set), two large motors, one medium motor, one touch sensor, one color sensor, one infrared sensor and an infrared remote. Lego also offers another edition called the Education Set.

DAVID LUDERS, FLICKR

7

“Fllying Lemur” EV3 Robot

8 The Education Set has fewer building elements, but there is an additional touch sensor and ultrasonic sensor, as well as a gyro sensor.

The Education Edition does not include an infrared sensor or remote. It is a good choice for those who are interested in doing science experiments and logging data, as the sensors and software are designed for such projects.

Lego Mindstorm EV3 Expandable Grabber Claws

Get Things Moving

A good way to set a robot in motion is to give it a motor, and then program the motor to rotate. So, before building a robot, let’s start by getting the motor turning. To do this, you’ll need EV3’s programming environment, LabView, which can be downloaded for free.

Once LabView is installed, connect the brick block to the computer via the included USB cable, and a large motor piece to the brick via one connector cable. Open the LabView programming software and find the large motor block in the green palette.

Connect it to the play block. The large motor block gives several programming options. We can program it for a given number of seconds, a given number of rotations, or a given number of degrees.

We can also choose the rotation speed.

Testing the EV3 Robots

Next, download the program to the brick, and the program will appear on the brick’s screen. Select it to see the motor rotate.

Next Steps

Once we have a rotating motor, all types of possibilities arise. Attach wheels to make vehicles, rods to make swinging pendulums, and other Lego elements to design robots of endless variety.

With a bit of guidance from The Lego Mindstorms EV3 Idea Book, using 19 additional Lego pieces, we converted the motion of the rotating motor into that of flapping wings. Adding a second large motor lets our bird flap and roll at the same time.

Extendibility

One fun way to stand out among EV3 users is to turn an Android phone or tablet into a remote control using MIT App Inventor. For those looking to explore electronics a bit deeper, EV3 and Arduino can be used together, allowing access to all Arduino-compatible sensors. And for folks that program using Scratch and prefer not to learn a second drag-anddrop programming language, Scratchx.org has an EV3 extension. b

9

DAVID LUDERS, FLICKR

VRENI ARBES AND EUGEN GEBHARDT, FLICKR

VRENI ARBES AND EUGEN GEBHARDT, FLICKR

BY ERIN WINNICK

t s r i F r u Yo

Young people usually do not get a lot of opportunities to use machines. But there is one machine that can often be found in the backs of closets, just waiting to be discovered: the sewing machine.

Growing up, I loved learning to sew. I was able to transform 2D fabric into a 3D creation that had a use. I credit this experience with helping me become an engineer.

A sewing machine was my first experience with larger machinery.

Learning to control the speed with the pedal, changing the settings for my needs, and working with the needle were fantastic preparation for learning to use lathes and mills.

Learning how a sewing machine works is a great introduction to how manufacturing works.

Make Your Own Pillow

e n i h c a M

Additionally, with the rise in wearable technology and high tech fabrics, working with sewing and fabric can give you the chance to experiment with some new cutting edge technology. Fabrics are now being combined with lights, sensors and circuits, transforming clothes into the newest computers.

Read on to see how you can get started. Then check back in the next few issues for fun maker projects where you can combine sewing and technology!

RALPH HOGABOOM, FLICKR

Make It

10

If you are interested in buying your own machine, there are great starter models out there. These machines are made to be very user-friendly and will allow you to get to the next level. Check out the $39.99 Singer E-Z Stitch Toy Sewing Machine and the Haitral Sewing Machine Mini for $19.99.

Also, be on the look out for local makerspaces that have sewing machines. Many have been adding art and sewing into their tools, making them great places to learn. b

(Adult supervision required)

Before you try sewing on the machine, first get used to handling a needle and thread.

Learn to thread a needle, pin fabric together, and how to cut fabric. You’ll need thread, fabric, sewing pins, a pin cushion, and stuffing for the pillow. First, pick a fun fabric from the store.

Felt is a good starter fabric. Buy 1 yard of this fabric so that you have extra in case you need it.

Steps: 1. Cut two 18in x 18in squares.

2. Place these 2 squares on top of each other with their “right sides” facing each other.

3. Pin the 2 pieces of fabric together at all of the corners and in the center of each side.

4. Cut a LONG piece of thread and thread your needle. (it’s always better to have extra thread than not enough.)

5. Push the threaded needle through both layers of fabric about 1 inch away from the side.

Pull extra thread all the way through.

6. Repeat step 5 until you have gone around the whole edge of the pillow, but leave a 4-inch gap between where you started and where you end.

7. Tie off your thread on both sides of your seam. Turn your new pillow right-side out.

8. Fill your pillow with the stuffing to the firmness you would like.

9. Sew your 4 inch gap closed. Your new pillow is done!

LIZ68022, FLICKR

★

If you’ve ever tried to draw a star, you probably realized that it’s harder than it looks. Well, luckily there’s an easier way: using Python and Turtle.

Python is a simple programming language that allows you to focus on logic instead of worrying about brackets and semi-colons. Turtle is a Python module—sort of like an extension to the main language— that makes it easy to draw things.

There are two main components in a Turtle program. There’s the ‘screen’, or the canvas on which you draw. Then there’s the turtle, who draws the shapes you request.

This virtual turtle is often it’s shaped liked a little triangle, but you can change that if you like.

1. Go to www.repl.it and type ‘Python’ in the box, but make sure you select ‘Python (with Turtle)’.

Otherwise, the code won’t work!

2. Paste the following code in the left-hand editor: from turtle import * thomas = Turtle() thomas.color(“red”) for i in range(5): thomas.forward(50) thomas.right(144)

3. Hit the run button! Your ‘turtle’ should draw a star on the righthand screen.

The Spiral Star To finish off the activity, we’re going to draw something extra cool: the spiral star. There are two small changes we must make to the code:

Change ‘range(5)’ to ‘range(20)’ (if you haven’t already). Change ‘thomas.forward(50) to thomas. forward(i * 10)’ Now hit the Run button and see what happens! We know that loops are good when we’re repeating an action. But what if it isn’t exactly the same action?

In every loop, there’s one value that changes at each run through— the variable i. On the first iteration, i=0. Next, i =1, then i=2—all the way up until i=19 (the for loop stops right before it gets to 20).

And since the value of i is always changing, we can use it to make Thomas draw lines of different sizes. At first, when i = 0, the line is length 0. Next, when i = 1, the line is of length 10. Then 20, 30…all the way to 190! As in the previous example, try playing around with the key numbers in the code 20, 10, and 144 and see what happens.

Have fun! b

from turtle import * Turtle is a module, so it’s not included in the program. This line of code fetches the module from its ‘shelf’ and brings it into the work area. thomas = Turtle() This part—Turtle()—creates a turtle object. An object is a virtual data structure with special traits and abilities; in this case, the ability to move, draw, and change shape. Altogether, this line of code creates a specific turtle and assigns him to the variable ‘thomas’. thomas.color(“red”) By default, Thomas draws with a black pen. This code changes the color to red, but just change the word ‘red’ to the color of your choice—keep the quotation marks. for i in range(5): This creates a ‘for loop.’ They’re useful in programs that have a lot of repeated steps. Instead of telling the program to ‘draw one side of the star, then the second side, then the third side, etc.’ you can use a for loop to say ‘draw a side, then do it five times.’ ’range(5)’ controls how often the code inside the loop is repeated—in this case, 5 times. What will happen if you change the ‘5’ to a ‘4’? Or increase it to ’10’? thomas.forward(50) We’re telling our turtle, Thomas, to move forward ’50’ pixels. You can put any number larger than 0 between those two brackets. The bigger the number, the bigger the star that Thomas will draw. Start this line with a tab.

Yes, thomas.right(144) In preparation for drawing the next side of the star, Thomas has to we turn a bit. In this case, we tell Thomas to turn to the right by 144 degrees. A full circle is can!

360 degrees and a half circle is 180 degrees. Therefore, 144 degrees is not quite a half circle. What do you think happens if you turned more than 360 degrees?

‘144’ is the magic number for creating a perfect star. Otherwise, Thomas will turn too much or too little, and miss the point where the lines should meet. This isn’t necessarily bad. You can create lots of neat spiral art by changing the angle, they just won’t be stars. Try 100 and 165 degrees. You might also want to increase the number of repetitions, i.e. changing ‘range(5)’ to something like ‘range(20)’.

NICOLAS LABYRITHX, FLICKR

11

Coding

s e l t r u T w e n K o h ?

W w a r D d l u o C

BY PATRICIA FOSTER

Puzzles

12

BY PATRICIA FOSTER

The Birthday Paradox

Sharing your birthday with someone can be fun, but having a day all to yourself is nice, too.

Especially since you get to pick the party’s theme (for me: always dinosaurs) and you get the largest slice of cake. Let’s say there are 23 people in your class. What are the odds that two people share a birthday? Not too good, right? After all, there are 365 days in a year.

Would you be surprised to learn that in a class of 23 people, there’s a 50% chance that two or more people share the same birthday?

And in a group of 50 people, that probability jumps to 97%?

We call this the Birthday Paradox (or the Birthday Problem) because it’s a result that doesn’t feel right.

Let’s take a look at the math.

First, a basic rule of probability: if no one has the same birthday, then everyone must have a different birthday. Let’s picture this scenario using a prop. If you own a Scrabble board, use that. If not, then a chess or checkerboard will work. Or, draw a grid on a piece of paper! Pretend that this board represents a year, and each square is a single day. Ideally, we’d want a grid with 365 squares, but we can use our imaginations to pretend we do.

Each person puts a tile on the day of their birthday. So if two people were born on the same day, then two tiles would be stacked on top of each other, but we don’t want this in our scenario.

The first person to go is an imaginary person. Let’s pretend he is named Thaddeus. Like anyone else, he has 365 possible birthdays.

Any day is as likely as any other, so for now, put the tile anywhere on the board.

Next, imagine a second person; her name will be Anna. In this scenario everyone has a different birthday so Anna has 364 possible

birthdays except the one already occupied by Thaddeus. Add Anna’s tile to the board, avoiding Thaddeus’s square.

Imaginary person number 3: Skylar. Because Skylar can’t have the same birthday as Thaddeus or Anna, that leaves 363 possibilities.

Can you see the trend? With every person we add, there’s one less possible birthday. It doesn’t matter exactly when each person’s birthday is, because we know that it’s taking up a space on the Scrabble board. As

13 you’ve probably guessed, there are hundreds of valid ways to arrange these three different tiles on the board. In math, we refer to a specific arrangement as a permutation.

Now, a fundamental rule of probability: when calculating the probability of an event, you take the number of good scenarios (each person has a different birthday), divide it by the number of general scenarios (each person has a random birthday), and multiply it by 100.

In this case, the good scenarios are boards where no two tiles overlap, and the general scenarios

are boards stacked any which way.

The tiles could be evenly spaced, or maybe they’re all stacked on top of each other. It doesn’t matter; there are no rules for the general scenario!

Counting all these scenarios is a bit tricky, but the end result (for 23 people) is a formula that looks like this: 365 365

X

364 365

X

363 365

X

362 365

X...X

(362-22) 365

X 100

Wolfram Alpha (a computational knowledge engine) has a ‘Birthday Problem Calculator’ that crunches these numbers for you. You can use it to calculate the probability that two or more people share a

birthday in a group of any size.

http://www.wolframalpha. com/input/?i=birthday+ problem+calculator Counting things, such as figuring out all the ways that groups of tiles can be arranged, is a branch of math called combinatorics. It’s an important branch of math for computer scientists. And it teaches us something important about the way our brains work: when we sit down and do the math, we sometimes discover that a sensible result is completely wrong. Math works in weird, surprising ways; it’s important to not jump to conclusions. b

KIRAN FOSTER, FLICKR

Scratch

14

BY CLARISSA LITTLER

Getting Started with Scratch

Scratch is a kind of programming language and interactive art studio rolled into one. To get started, go to https://scratch.mit.edu/ and click on “Try it out” You should see something like this:

The little cat is a sprite. Sprites are little robots we can program. They can move around, change color, play sounds, and even respond to their “senses”. Sprites can also talk to each other to coordinate their actions. The big white space the sprite is sitting on is the stage. Under the Scripts tab are all the tools you can use to program your sprite.

• Use Motion to move the sprite.

• Looks changes its appearance.

• Sound lets it play noises.

• Pen allows the sprite to draw as it moves so you can make pictures with your code.

• Data is for storing information.

• Events tell the sprite when to do something or exchange messages with other sprites.

• Use Control to tell the sprite to repeat an action or make choices • Sensing allows the sprite to use its senses, like touch or sight • Operators are for math and logical operations

• More Blocks are for extensions to Scratch or to define your own reusable code, like functions in other programming languages Let’s do a very small program together. If you’ve done some programming before, Scratch is going to be a little different. Rather than typing, you’ll be moving and combining blocks.

Using your mouse, drag the move 10 steps bar onto the blank space, and do the same with the turn 15 degrees bar: Now, the cat sprite moves every time you click on the move block and it rotates every time you click the rotate block.

How do we sequence these steps, or, how do we make one happen

after the other? We combine them by dragging them together, so it’ll look like this. If you click of them, both things will happen.

If you want to make the sprite’s motion more dramatic, increase the numbers by clicking on them.

Add other sprites (or create your own) by clicking on the button in the pane just above the sprites.

Click Events to run this like a program. Drag the when (green flag) clicked to your little program and put it at the top of your code.

Now hit the green flag button you’ll make the cat move.

To change the backdrop of the stage, click on the buttons just under the words “New backdrop”.

You can open a new backdrop from the options provided, upload one, or create your own.

To get rid of sprites or unwanted code use the scissors symbol at the top of the screen. Click on the scissors, then on what you want to remove. Save your programs to the computer using the “File” button at the top of the screen. You can also upload saved code from your computer. Make an account to save what you make and access them from any computer.

Next time, we’ll make some small games and some actual programs in Scratch. Until then, practice what you’ve learned here and follow the tutorials available by clicking “Tip” on the gray bar at the top of the screen.

See what you find! b

15

BY SIMON BATT

No doubt you’ve heard of Minecraft. It’s a game of exploration, creativity, and adventure. Perhaps you want to start playing, or perhaps your friends have already jumped in and are begging you to join in! But what is Minecraft about?

Minecraft is what’s known as a sandbox game. There are no preset game conditions or story that the player has to follow. There is a way to ‘end’ a Minecraft game, but it’s entirely up to you if you want to chase that. Otherwise, the game simply hands you a world to explore and lets you do whatever you please.

Because a Minecraft world is made up of blocks, it allows you to build anything you like. Want to build a house you can live in? How about a castle? How about a cave fortress, complete with traps? It’s up to you!

Minecraft’s world is different for every player. It’s created by what’s called ‘procedural generation’, where the world is randomly created using set rules rather than being designed by hand. The worlds are also gigantic, so you’ll always have somewhere new to explore! Take a sword, a shovel, a pickaxe, and collect ores and items as you go.

Minecraft offers adventure too. Dark caves, abandoned mineshafts, and even alternate worlds full of danger!

You’ll find

ores with which to forge weapons and armour, enchant them using magic, then brave the depths and try to make it out!

One interesting element to Minecraft that will appeal to computing types is its redstone mechanics. You can find redstone while mining, which you can then spread on the ground as powder.

Using torches also made of redstone, you can send a charge down this line of powder, activating anything connected to it.

Minecraft also is open for modding. That’s the ability to download (or even create!) additional content for the game, absolutely free. Many Minecraft players have created and uploaded mods to websites such as Minecraft Mods and Curse.

Use these mods to enhance your favorite areas of Minecraft. If you enjoy building and designing, you can download furniture and patterns with which to decorate. If you like exploring, mods can add new worlds. If adventure is your thing, download mods that add weapons to the game. If you enjoy redstone, you can download mods to power automated machines!

For more fun, Minecraft offers with the ability to play with friends! What makes online play really fun is the combined effort of a lot of players, meaning you can find some very impressive structures MINECRAFT IMAGES BY MIKE PROSSER, FLICKR

Minecraft

Getting Started with Minecraft that would otherwise be a chore to make alone!

As with all online games, be careful when entering a server for the first time. Minecraft servers can be occupied by ‘griefers’: people who like insulting others in the text chat and destroying their creations. Try to make sure you join a server with mods installed that prevent other players from ruining your creation. A lot of Minecraft communities have their own servers, so if you find yourself in one, it’s a good idea to join it and play with likeminded people!

Sounds fun, but where to start?

First, head over to the Mojang website. Click the ‘Buy Minecraft’ button, or head to their store to see other options, including Xbox and mobile versions. You’ll make a Mojang account. Your account will connect your purchase to you and act as your login to Minecraft, so create a safe, memorable password. Minecraft is $26.95 at presstime. Download the Minecraft installer. Install it onto your PC and you’re ready to go!

Play the game and get a feel of what you enjoy. Next issue, we’ll discuss some in-game activities. b out the , check of e r o m n ver To lear ack co n the b links o ue. this iss

16

BY CLARISSA LITTLER

Coding

d n a m m o c f o n i a ch Predicting Words and Creating Random Stories with Markov Chains

Predictive text is a technology you’re probably very familiar with from things like smartphones and tablets. Every time you type or choose a word, you get a choice of other words that can come next.

How does a phone choose what text to suggest next?

In this article, you’ll learn a simple technique for making your own text predictors as well as how to generate text in the style of a particular author!

The trick for both of these is an old mathematical concept called a Markov chain. A Markov chain is basically a process that can have a number of “states” it can be in, and whose next “state” is determined randomly. Flipping a coin over and over is a Markov chain with a single state. What about a Markov chain with multiple states?

Picture a checkerboard, or grab/ draw one if you’d like, and put a coin down on it. Roll a four sided die to determine which direction to move next: up, down, left, or right.

If you can’t move a direction, then you stay where you are. This is a Markov chain where the states are the squares on the board.

SAM CARPENTER, FLICKR

How does a game like this help us generate text? Imagine a different kind of board, where the squares represent the last several words you’ve seen, and moving to another square means choosing a word that comes next.

There are a lot of words in a language, many more than just the four directions in our checkerboard example. How do we choose which comes next? If we choose any word with equal probability, on some imaginary 250,000-sided die, we’d get things that don’t sound anything like English! “The a his the the fish” would be as equally likely a sentence as “The ball rolled down the hill”.

We don’t have to be experts in languages to figure out what the probabilities should be, though.

Instead, we can cheat a little and figure it out by taking a large example of the language, like a novel, and go through the entire document counting how often we see combinations of words. What we’ll have at the end is the big table of the probabilities you need for

choosing different words based on what the previous several words you’ve seen are.

So as an example, imagine that the last three words you’ve generated are [‘I’,’am’,’so’] and the probabilities for the next word are a 20% chance of “awesome”, 40% chance of “tired”, and 40% chance of “late”. If the next word picked is “tired”, then the new “state” will be [‘am’,’so’,’tired’] and the process continues.

You can generate as big a piece of text as you want by repeating this process over and over to keep choosing words. To predict text, instead of choosing text by its probability, you offer suggestions based on how likely they are and let the user make the final choice.

We’ve said that you use “the last few words”, but how many words should you remember when generating text?

The answer is: it depends.

The more words you remember, the more the generated text is just going to look like the source material you used to build the

e g a u g n a l of Markov chain. If you remember only one word, you’ll get gibberish that isn’t grammatic. If you remember ten words, then you’ll get entire sentences and paragraphs that are straight out of the source. The sweet spot is somewhere in the middle, where you’ll get something that’s grammatically correct but isn’t just a direct quote of something that came before..

Below is most of a small Python program that reads in such a text file, and then runs the Markov chain process to generate a large number of words. The one thing to note is that numWords is the number of previous words you’re using for prediction. def groupWords(text): ourDict = {} group = [] for w in text:

if len(group) == numWords:

if ourDict. get(tuple(group)) == None: ourDict[tuple(group)] = [w]

else:

ourDict[tuple(group)].append(w)

group.append(w)

group = group[1:] else:

group.append(w) return ourDict def markovMulti(numTimes,ourDict): outwords = [] testGroup = [] for i in range(0,numTimes):

if(len(testGroup) < numWords):

testGroup = list(random. choice(ourDict.keys()))

outwords = list(testGroup) else:

w = random. choice(ourDict[tuple(testGroup)])

testGroup.append(w)

testGroup = testGroup[1:]

outwords.append(w) return “ “.join(outwords) You can adapt this code into predicting text instead of generating text. Make a program that will initially present the five most common words as options

17 and give the option to choose one of those or write your own word.

Repeat this until you have enough words to start the prediction. For example, if you chose to predict text based on the last three words then keep going until you have three words.

Once you have enough words that you can start predicting text, show the five most common next words, given what’s already been typed, and give an option to choose your own.

If the current history of words doesn’t have any matches for prediction, go back to showing the five most common words.

A Python program that does this is available. Look on the back cover of this issue for the link that corresponds with this story. Try playing around with the number of words used in prediction as well as making the text prediction more complicated. You can try making it learn over time, recording the words you choose and making them more likely to show up again! b

To learn more, check out the link on the back cover of this issue.

circuits

18

Whatâ&#x20AC;&#x2122;s a micro

BY LES POUNDER

The micro:bit was released in 2016 as a low cost micro-controller board for middle school students in the United Kingdom to learn the basics of coding. Code is written using an online editor and then copied to the micro:bit which appears as a USB flash drive. Find micro:bits at http://microbit.org/resellers/

16Kb RAM

micro:bit 101

compass

Go to https://pxt.microbit.org. Start with a blank project. The pxt editor is block based, meaning that you click on the block menu (left center of the screen). To open a menu, click on it and you will see the blocks it contains. This will show an expanded window that will briefly cover the coding area, to the right of the screen. Blocks can be moved from the menu to the coding area and connected in the same manner as with Scratch.

temperature sensor

The micro:bit pxt blocks interface looks and feels like the Scratch editor.

On the left of the screen we have an interactive micro:bit simulator that enables us to test our code before we deploy it to the real hardware. Very handy!

The basic menu expanded, showing all of the blocks in that menu.

Want more?

Look on the back cover of this issue for a link to more micro:bit projects.

:bit?

19

5X5 LED matrix memory

built-in accelerometer enabling basic gesture control

Bluetooth 16Mhz ARM processor two buttons five GPIO (General Purpose Input Output) pins

radio to send data

256Kb flash memory DOMINIC CONNOR, THEREGISTER.CO.UK

Project: Stop Shaking Me! You’ll need a computer with an internet connection, a micro:bit, headphones, 5 x Crocodile clips, a 10k potentiometer, and an LED.

1

Clear the “on start” and “forever” blocks from the coding area. Drag them one by one to the blocks menu, and drop them. Now go to the Input menu and drag the “on shake” block to the coding area.

This is our input that will trigger the code that we will write inside this block.

2 First, let’s scroll a message across the LED

What will happen when we shake the micro:bit?

matrix. Use the “Show string” block from the Basic menu. Drag this block so that

it is inside “on shake” Now change the text to say “Stop shaking me!!!” Again from the Basic menu, drag a “pause (ms) 100” block, and connect that to the previous block, but change the value to 500ms, half a second.

3 “show icon” block. Connect this to the previous Go back to the Basic menu and look for the

block. These icons are small pixel images that use the LED matrix to display an image. Change the icon by clicking on the small drop down arrow to the right of the icon. We changed ours to an angry face: our micro:bit did not like being shook!

Our last block is another “pause (ms) 100” from Basic, again we change the value to 500ms, half a second.

4 connect your micro:bit to your computer using Download the code to your computer. Then,

a micro USB to USB lead. Your micro:bit will appear as a USB flash drive. Copy the downloaded file to the flash drive and your micro:bit will reboot. Give it a shake, and watch the code come to life! b

BY TIM SLAVIN

b safe onl;ine

20

d e e F t ’ n Do s l l o r T e th !

ngry I’m hu

R. NIAL BRADSHAW, FLICKR

To learn more, check out the link on the back cover of this issue.

It’s exciting to be online with friends and family, but it can also be a bit scary. People often say things online they never would say in person. When people are rude again and again, they’re called trolls. The number one rule for being online is, “Don’t feed the trolls!” Don’t give them any reason to continue to bother you.

But what should you do if you find a troll online? First, control your privacy settings anywhere you are online. Don’t give out your last name, for example, and only connect with family and good friends. Unfriend people who are mean to you. Common sense actions to protect your privacy and limit who can contact you is a key step to avoid trolls.

Second, learn how to take screenshots. On a Mac, for example, press the Command, Shift and 4 buttons at the same time to trigger screenshot mode (Windows: Print Screen), then drag the little cross hair icon across the screen, then unclick the mouse to snap the image. Paste them into an email and mail to yourself and a parent or trusted adult like a teacher.

Saying mean things online is bullying, same as in the real world at school, home, or with friends.

It’s not acceptable. The same rules apply. Be respectful at all times. But if a troll does show up, document it. You’ll have that proof of the troll’s bad behavior. Get help, and limit your contact with the troll.

The most important advice?

Don’t blame yourself. It’s hard to figure out who you are, what you like and don’t like, and lots of other things. What a troll does is wrong.

It’s not about you or who you are.

Their bad behavior is their problem.

It’s also true parents and teachers want to help. If a troll should wander into your life online, don’t be afraid to ask for help. b

Schattenbilder

Shadow Pictures

Art, software engineering, installations based on shadow design, architecture, and casting and the images they cryptography all come togther create. This exhibit was installed in the amazing projects that the at the Swiss Science Center Zurich-based team of Drzach & Technorama.

Suchy create.

One of the three, called “TikDrzach is a Swiss and Tak” (that’s German for tick-tock, American-educated architect the sound of a clock), shows the who designs furniture pendulum of a clock and portable display Depending on What you see moving. spaces. Suchy, also its position, light hits the educated in Switzerland depends how textured surface of the and in America, is a pendulum differently, you look at it! thereby causing you to cryptographer and software engineer. see either the word tik, Their unique partnership is tak, or something in between! responsible for many projects that If you look at “Conversation,” beautifully blur the line between below, you will see either a science and art. portrait of Albert Einstein or One of their projects is called Marilyn Monroe, depending on Schattenbilder, which means the direction from which the Shadow Pictures. Many of their light is shown. For more on this exhibitions explore light and its remarkable duo, look on the back effect on form, as this one does. cover of this issue for a link to In 2011 they prepared three their work. b

“tik-tak” in position 1

“tik-tak” in position 2

“tik-tak” in position 3

IMAGES FOR THIS STORY FROM WWW.DRZACHSUCHY.CH

21

show and tell

BY KELLEY LANUTO

tidbitz

22

tidbitz You Can’t Hear This

Many phone apps now use ultrasonic tones to track consumers.

They ask permission to access your smartphone microphone, then listen for inaudible ultrasonic “beacons” that emanate from retail stores, advertisements, and websites. If you don’t pay attention to the permissions you grant your apps, you might give marketers information about your online browsing.

There are good uses of this ultrasonic tracking technology.

However, many apps include this functionality without a clear use case. There are 234 current Android

applications that incorporate a type of ultrasonic listening technology. That’s not a lot, but the infrastructure to support it is in more apps every year. These apps might have the function turned off today, but they can switch it on tomorrow.

It’s easy to accidentally to turn on ultrasonic beacon tracking. You only have to grant microphone permissions absentmindedly.

Tracking can work even when you’ve disconnected your phone from the internet.

There’s also a risk of incidental data collection. With any “always on” sensing technology, the risk of abuse is always possible.

To assess the privileges you’ve granted your apps on Android 7, navigate to Settings, then to Apps.

Tap the gear icon in the upper right, then tap App Permissions to see and edit the privileges you’ve granted each app. To do this on iOS 10 go to Settings, then Privacy, then Microphone.

Of course, for every bad thing on the internet there’s eventually a good thing. Researchers have created a Chrome browser extension and at least one software patch. However, checking your app privileges is always the safest solution. b

—Adapted from the article by Lily Hay Newman, “Hundreds of Apps Can Listen for Marketing ‘Beacons’ You Can’t Hear,” wired.com, 5/2/17

https://www.wired.com/2017/05/hundreds-apps-can-listen-beacons-cant-hear/

Say What?

Word Embedding, a set of AI learning techniques that help computers understand how humans speak, has been shown to exhibit gender and racial biases.

These techniques derive meaning from massive online databases that contain a wealth of human knowledge. The AI software compares each word with the words used around it. However, reading and understanding these texts has also caused computers to repeat back the cultural biases in the texts.

For example, the words “female” and “woman” were more closely associated with arts and humanities occupations and with the home, while “male” and “man” were closer to maths and engineering professions.

The AI system in a research report published recently in Science, also was more likely to associate European-American names with pleasant words, while African-American names were more commonly associated with unpleasant words.

Unless explicitly programmed, algorithms will be riddled with social prejudices. Sandra Wachter, a researcher in data ethics and algorithms at the University of Oxford, said in a recent Guardian article that this could present an opportunity to address bias and counteract it where appropriate.

“We can, in principle, build systems that detect biased decision-making,” said Wachter.

“This is a responsibility that we as society should not shy away from.” b —Adapted from the article by Hannah Devlin, “AI Programs Exhibit Racial and Gender Biases, Research Reveals,” The Guardian, 4/13/17 https://www.theguardian.com/ technology/2017/apr/13/ai-programs-exhibitracist-and-sexist-biases-research-reveals https://en.wikipedia.org/wiki/Word_ embedding

 New Coders Speak Out

More than 20,000 adult coders who have been coding for less than 5 years responded to 2017 New Coder Survey. Who are they?

Here are some of the findings: • • • •

•

62% of them live outside the US. Their average age is 28.

19% are women.

They’ve been coding for an average of 21 months.

25% have already landed their first developer job. b

—Adapted from the article by Quincey Larson, “We Asked 20,000 People Who They Are And How They’re Learning to Code,” medium.freecodecamp.com, 5/4/17 https://medium.freecodecamp.com/we-asked-20-000-people-who-they-are-andhow-theyre-learning-to-code-fff5d668969

Think Your Way Out of a Paper Bag

MARK SEBASTIAN, FLICKR

Did you know that a long time ago many people thought inventing was too complicated for women? But Margaret E Knight knew differently.

She left school at age 12 to work in a textile factory. After she saw a machine injure a worker, Knight invented a device that automatically stopped the machines if they malfunctioned. Her invention was adopted by factories all over the United States.

Because women at the time were discouraged from filing for patents, Knight’s device was never patented and she never made money from it.

Having a patent means that only you can manufacture and profit from your invention.

After the Civil War, she worked at a factory that made paper bags. She loved to solve problems and noticed that shoppers carried their purchases in crates or paper cones or thin envelopes. Her idea was to use a metal plate to fold paper into a sturdy square bag with a sealed bottom…the modern paper bag we still use today. Then, Knight worked with three companies to build a version of her device in iron.

When she went to file a patent, Knight found someone already had after seeing her invention. Luckily, she had lots of notes, drawings, and fought for the patent in court. It was granted to her in 1871 and she went on to file and get at least 27 more. Some say she filed as many as eighty patents in her lifetime. b —Adapted from the article by Stephanie Buck, “Thank Inventor Margaret E. Knight for the Modern Marvel That Is the Paper Bag,” timeline.com, 4/15/17 https://timeline.com/margaret-e-knight-paper-bag-f5d474c0f3d2 http://www.women-inventors.com/Margaret-Knight.asp https://en.wikipedia.org/wiki/Margaret_E._Knight

23

Wonder Women

There are many ways to help young women turn their interest in technology into careers. The Virtual Reality Foundation in Los Angeles has one great idea: pick a new technology then help young women learn the technology and grow with it. In this case, the new technology is virtual reality and augmented reality.

The Virtual Reality Foundation puts on VRLA as a trade expo and within it a Girls Make VR workshop program that teaches women ages 13-18 the potential of virtual and augmented reality technology and how to use it.

No Bones About It

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https://arstechnica.com/ science/2017/04/no-bones-neededancient-dna-in-soil-can-tell-ifhumans-were-around/

IMAGE FROM WEBSITE OF VRLA

24

Despite being a new technology, virtual and augmented reality attracts mostly young men into gaming and entertainment. Of course, young women also are into gaming and entertainment. VRLA and Girls Make VR are designed to get them excited and involved.

And of course, women can bring a different approach to technology based on their experiences, especially kids who live in big cities and maybe live in poverty.

They might come up with very different uses for VR. VRLA hopes to encourage them.

The expo workshop also is intended to evolve into weekly workshops and mentor programs to transition interest into skills and jobs.

A recent LA Weekly article about VRLA featured Jasmine Chau, an 18-year-old high school senior. She joined the Girls Make VR workshop after hearing about it from a teacher. “This experience really helped me narrow down what I want to do in the future,” Chau said. She’s interested in computer science and may end up majoring in the subject when she goes to college. “I like plugging in stuff and problem solving,” she says. “This is definitely within the realm of things I like to do.” b —Adapted from the article by Liz Ohanesian, “Teen Girls Are Closing the Gender Gap in VR,” LA Weekly, 4/17/17 http://www.laweekly.com/arts/vrlaprogram-girls-make-vr-aims-to-close-thegender-gap-in-virtual-reality-before-itwidens-8136760 http://www.virtualrealityla.com/ http://www.marketwired.com/pressrelease/virtual-reality-foundation-launchesfirst-ever-girls-make-vr-workshop-vrlasummer-expo-2147751.htm

Humans have lived in a famous cave in Siberia, the Denisova Cave, for tens of thousands of years. The items they left behind help scientists understand how humans evolved. These discoveries led scientists to call these humans Denisovans, a species related to Neanderthals.

Because human bones deteriorate over thousands of years, there has been little or no evidence of humans beyond their tools and garbage.

But new technology no longer requires bones to tell if humans, and what humans, lived in a place. The soil they lived with has traces of their DNA. And DNA testing can tell scientists what species of humans lived in caves like the Denisovan cave.

The research used soil from four different caves in Europe. They searched for mitochondrial DNA, genetic material separate from the main cell DNA, because it evolves faster and is in more copies of each cell. Only a teaspoon of dirt was needed to find traces of humans. Scientists can create a more detailed picture of who lived in these places and when.

In a recent Ars Technica article, Christian Hoggard, an archaeologist at Aarhus University not involved with the research, said, “This is a game changer for researchers studying our hominin past.” Another researcher who specializes in dating bones, Tom Higham from Oxford University, called the discovery a “new era in Paleolithic archaeology.” b —Adapted from the article by Cathleen O’Grady, “No Bones Needed,” arstechina.com, 4/29/17

Watch This Space

On Monday, August 21, 2017, all of North America will be treated to an unusual sight. Anyone within the path of totality can see one of nature’s most awe inspiring sights—a total solar eclipse.

This path, where the moon will completely cover the sun and the sun’s tenuous atmosphere—the corona—will stretch from Salem, Oregon to Charleston, South Carolina. Observers outside this path will still see a partial solar eclipse where the moon covers part of the sun’s disk.

NASA has set up an eclipse website, as well as web pages about how to make a pinhole camera, learn about moon phases, use pi to do all kinds of astronomy calculations (like eclipses!), and find out about exoplanets (planets found around other suns like ours).

The pinhole projector page includes STL files to print in the shape of your favorite state. Sites like Shapeways and 3DHubs make it easy and inexpensive to print your own. Plus they show how to use your hands as a pinhole camera. The traditional pinhole camera is made from paper, aluminum foil, scissors, and tape.

The NASA site also includes a tool to figure out the best places to watch the solar eclipse from anywhere in the world, not just North America. And remember: never look directly at the sun!

So put August 21st in your calendar, then get outdoors to see something amazing and rare! b https://eclipse2017.nasa.gov/ http://eyes.jpl.nasa.gov/eyes-on-eclipse.html https://eclipse2017.nasa.gov/3d-printable-pinhole-projectors https://www.jpl.nasa.gov/edu/learn/project/how-to-make-a-pinhole-camera/ https://www.jpl.nasa.gov/edu/teach/activity/moon-phases/

NASA, ROMEO DURSCHER, FLICKR

Plastic Rocket Men

https://www.jpl.nasa.gov/edu/teach/activity/pi-in-the-sky-4/

Recently, the Rocket Team at MIT successfully fired a rocket motor printed from plastic. Three students spent two weeks working to design and print the pieces necessary to make this a success. Printing rocket motors from plastic is a unique accomplishment. Several groups, including SpaceX and NASA, print rocket engines from metal. But metal printers are expensive, costing more than six figures. This plastic motor is produced on an innovative, lower-cost plastic printer, which has a price that’s within reach of hobbyists and small teams. Additionally, the case is designed to work with modern composite propellants. The team has already begun follow up work to explore larger motors, more resilient motors, and potentially even flight hardware. b —Adapted from the article by Charlie Garcia, “100% 3D Printed Solid Rocket Motor!,” MIT Rocket Team Newsletter, 4/25/17 http://rocketry.mit.edu/2017/04/100-3d-printed-solid-rocket-motor/

BRIAN TOMLINSON, FLICKR

25

Offbeat

26

The Fascinating Barbed Wire?

BY TIM SLAVIN

You’re probably wondering why a story about barbed wire, of all things, is in a magazine about technology.

You might think barbed wire is extremely boring and has no connection or parallels with computer technology. After all, it’s just wire twisted and sharpened and strung between fence posts, end of story.

Maybe you have never seen barbed wire.

Yet it’s true barbed wire is actually a technology. There are hundreds, perhaps thousands, of patents for different kinds of barbed wire. And the history of barbed wire as a technology and in the field is as contentious as the tussles over software

patents are today.

As European immigrants settled in the United States and spread out across the continent (to the detriment of Native Americans, I should note), they wanted fences to mark off their farms and properties. On the east coast of the US, people used stones to mark off property limits. Elsewhere, people built wood fences. Because there are few trees across the great plains, and the soil is not as rocky as it is on the east coast, wood and rocks were not available to make fences. Barbed wire solved this problem and protected property from trespassers. Barbed wire kept your livestock at home.

Today, a big, hairy software programming problem might be how to capture, store, and retrieve activity data for millions of users. With barbed wire, a big, hairy problem was truly big and hairy: a bull or cow that refused to let barbed wire stop them from wandering free.

An online search for the history of barbed wire turns up one notable fact: the person who invented barbed wire was not the first to make money on it. Or the first to hold a patent. The idea was stolen, in other words.

Henry M. Rose, a farmer, displayed a wooden rail with sharp

wire points to be attached to a fence rail at the DeKalb County Fair in 1873. Today people attend technology conferences to learn how to become better software programmers. In 1873, you attended the county fair to learn about the latest products and meet people who could help you be a better farmer.

Three men examined Rose’s invention and turned it into a product. Instead of a wooden rail, the sharp points were attached to a single wire. This design is still used today.

So how many ways can you design barbed wire? The United States National Park Service site notes there are over 500 patents on barbed wire, with over 2000 variations of these. Because individual farmers rolled their own barbed wire, they used designs they had seen and added their own improvisations, or created their own new designs. Much barbed wire was not wire. It was made of patterns cut from steel with sharpened edges, attached to wire.

The primary benefit of barbed wire for fences is its simplicity.

You only need the wire, fence posts, and staples to attach wire to the posts. Sounds like building a simple do-it-yourself website with Wix.com, WordPress.com, Blogger.com, or something similar.

To learn more, check out the links on the back cover of this issue.

b

History of…

PHOTOS: THIS PAGE BY@DEBJAM, FLICKR, PREVIOUS PAGE (TOP) BY PAT O’MALLEY, FLICKR, (MIDDLE) BY ERRAN CAREY, FLICKR (BOTTOM) BY ::ERWIN, FLICKR

27

Parents and Teachers

28

BY JENNIFER NEWELL

Girls and Comp In spite of the fact many of computer science’s early pioneers were women, CS has grown into perhaps the most male-dominated branch of science in both industry and academia. During the late 1990’s this trend sparked interest from both social and computer scientists. Since then, several studies have been conducted to determine how this gender gap arose, and how to attract more girls and women to this fascinating field.

The studies’ findings are similar.

They rarely, if ever, reveal females’ inability to grasp computer science concepts, and only superficially discuss females’ interest in the subject. Instead, the most significant factors include socialization, confidence, and presentation of the subject.

Although the underpinnings of computer science lie in advanced mathematics, and computer scientists apply challenging logic to write complex code, many in the field began exploring the subject at a young age. How can this be? Are they all child prodigies?

As it turns out, typing in snippets of code does not require much more than a bit of curiosity and an adventuresome spirit. Even the

beginnings of the logic involved in coding are not too complicated for an elementary school student to understand.

However, the more comfortable one is with testing out ideas and working with material that one only partially understands, the more likely one is to have fun with computer science at a young age.

These activities all involve risktaking and tolerance for failure.

In fact, once one moves beyond introductory projects, there is often a feeling of working in a black box in which the programmer cannot see exactly what she is doing.

However, by testing out ideas, a budding programmer will begin to understand how a program works before she understands the details of the math and logic.

Risk taking is an attribute more commonly associated with males than females. It may be partially “built-in”, but there is strong evidence showing that it is also a result of socialization. Psychologists studying children as young as four years old have found that parents tend to let their male children wander further at playgrounds than their female children before calling them back. Other classic

psychology studies examine how adults respond to infants based on gender. In one such study, psychologists John Condry and Sandra Condry had subjects watch videos of babies reacting to emotionally stimulating toys. Those who were told the infant was a boy frequently attributed crying in response to a jack-in-the box as the result of anger. Others were told the infant was a girl. When the infant began to cry in response to the toy, they attributed the reaction to fear.

Years of such subtle reactions and messages may teach girls to be more risk-averse than boys.

In fact, in their book Unlocking the Clubhouse, researchers Jane Margolis and Allan Fisher note that girls tend to be perfectionists and avoid risk taking at much higher rates than boys. When a riskaverse child is presented with an activity such as computer science that involves making guesses and learning through frequent failures, they often need extra encouragement to persist and have fun with the process. However, very few computer science classes offer such consideration.

Lack of interest is also frequently cited as a possible reason for the

ERIK (HASH) HERMAN, FLICKR

uters dearth of females in CS. In her work at Carnegie Mellon, Jane Margolis interviewed groups of male and female students regarding their early childhood experiences with computers and their attitudes toward programming as young adults. The findings are intriguing.

Males did indeed tend to have more interest in the technicalities of computers. There were more males than females that enjoyed tinkering with both hardware and software starting at a young age. They seemed to like coding for the sake of learning about the computer, and often became consumed by it, spending much of their teenage years engrossed in computer code.

The female students at Carnegie Mellon involved in the study were also top students that enjoyed problem solving and computing.

However, they seldom became obsessed with code. They emphasized they did not want coding to take over their lives, and they want to use computer science to help humanity. Indeed, the females in the study were very interested in computer science, but usually more in its applications to solve real-world problems than in the computer itself.

Unfortunately, traditional computer science classes focus more on the technical aspects of computing and less on its connections to real world problems and solutions.

Over the past 20 years significant effort has been put into applying these findings to increasing the number of female graduates from top computer science programs.

Carnegie Mellon offers a class that introduces computing with applications to culture, music, and visual arts. Harvey Mudd has an introduction to computer science class with applications to biology.

MIT, UC Berkeley, and Stanford also offer classes that focus not only on the technical aspects of computers, but also on projects involving art, game design, and data simulation. Other schools are following in their footsteps.

Families and schools can use these results to help children of any gender become excited about the subject.

We can encourage risk-taking in play, and become conscious of our tendency to attribute girlsâ&#x20AC;&#x2122; adverse reactions to fear.

We can also create inclusive, diverse computer science classes and clubs at home and in school

that include applications of the subject to real world problems, and connect computing to a broad range of interests. Jane Margolis and her team at UCLA developed a high school curriculum called Exploring Computer Science, written to give students a taste of varied applications of computers.

Bootstrap World curriculum appeals to middle and high school students and their teachers who enjoy mathematics. Google created CS First to encourage kids to start coding clubs. MIT has a variety of coding-related products designed for kids to have fun with while learning to code. Both boys and girls today have the opportunity to explore programming in ways that complement their interests.

However, there is still plenty of work to be done.

For those students who initially show a lack of interest or confidence, letâ&#x20AC;&#x2122;s not assume computer science is not for them.

Seek out guest speakers that use computer science in a variety of fields. Computer science is a broad field with myriad applications. It takes children months, if not years, to conclude that computing is, or is not, for them. b

29

“Creativity is allowing yourself to make mistakes. Art is knowing which ones to keep.”

—Scott Adams

Thank you for reading this issue of beanz!

Check out the links below to read stories from this issue online with links to learn more.

Create a Basic Cipher https://beanzmag.com/ create-basic-cipher

The Birthday Paradox https://beanzmag.com/ birthday-paradox

Don’t Feed the Trolls https://beanzmag.com/ dont-feed-trolls

On Sorting https://beanzmag.com/ on-sorting

Getting Started with Scratch https://beanzmag.com/ get-started-scratch

Shadow Pictures https://beanzmag.com/ shadow-pictures

Lego EV3 https://beanzmag.com/ lego-ev3-intro

Getting Started with Minecraft https://beanzmag.com/ get-started-minecraft

Tidbitz https://beanzmag.com/ tidbitz-august-2017

Your First Machine https://beanzmag.com/ first-sewing-machine

Chain of Command, Command of Language https://beanzmag.com/markovcreate-random-stories

The Fascinating History of Barbed Wire? https://beanzmag.com/ history-barbed-wire

What’s a micro:bit? https://beanzmag.com/ get-started-microbit

Girls and Computers https://beanzmag.com/ girls-computers-steam

Who Knew Turtles Could Draw? https://beanzmag.com/ turtles-can-draw