Introduction to coding

This video (1:49) from NASA is an engaging look into the importance of coding.

Block-based coding

Block-based coding is a visual programming method that lets you build programs by dragging and snapping together colourful, puzzle-like blocks. These blocks represent code commands so the advantage of this method for young learners is that it eliminates the need to type complex commands. The majority of coding activities in The SILO Project use the micro:bit and the free Makecode website (https://makecode.microbit.org/). Although you can set up free accounts on this site, you can use it without setting up an account. The following video (2:09) is also a very good introduction to the micro:bit.

The following picture identifies some of the components and features of the micro:bit.

Using buttons on the micro:bit

The following screenshot depicts an introductory activity using the two buttons on the micro:bit.

• Go to https://makecode.microbit.org/
• Click on 'New project'
• Add three pink 'Input' blocks
• Insert three blue Show LED blocks (found under 'Basic')
• Create a vertical line pattern for Button A, a horizontal line for Button B, and an addition symbol (+) for Buttons 'A' and 'B' together.

Making a game of speed and luck

This game uses randomly generated coordinates to light up an LED each time Button B is pressed. The aim is to illuminate all of the 25 LEDs as quickly as possible but the last ones are the hardest to get because the randomly generated coordinates will often be illuminating an LED which is already lit so it might appear that nothing is happening for a while.

Pressing Button A will clear the screen and restart the game. If other students have this game loaded on their micro:bits they can race each other by commencing the game at the same time.

Notes:

• The LEDs on the micro:bit form a 5 x 5 grid. The coordinates for the top-left corner are (0,0) and the coordinates for the bottom-right corner are (4,4). This explains why the code for choosing random coordinates is set from 0 to 4 for each axis.
• Most people are right handed which is why Button B was chosen as the button which is pressed rapidly. A left-handed person might wish to make a left-handed version where Button A turns on the LEDs and Button B resets the game.

Modify your game

Are the any other ways to speed this game up? What if Button A was assigned for some of the LEDs and Button B was assigned for the others? How could you describe this scenario in terms of probability?

Making a thermometer

The micro:bit can detect the temperature so making a thermometer is as easy as using the following code. An alternative to this could be to use a blue 'Forever' block so that the temperature is continually displayed and updated rather than having to press a button.

Conditional statements

When it comes to making a decision or moving towards an end goal, it involves the process of checking and taking action. You are going through the action of checking if something is true or false, and then taking the corresponding action based on your findings. We call the combination of IF and THEN in the process of making a decision a CONDITIONAL STATEMENT, and this is very useful in the instructional aspect of coding.

Let’s go through some examples where we need to check the conditions before taking action. Try and point out which is the condition, which is the action.

IF it’s sunny out, THEN wear sunscreen.

In this one, the first step is to check the weather to see if it is sunny. If the statement that it’s sunny outside is TRUE, we will put on sunscreen. If it’s FALSE, we do not need to.

• IF the gas tank is empty, THEN stop at the petrol station.
• IF the cake is under cooked, THEN increase the oven time. 
• IF the soil is dry, THEN water the garden.
• IF there is a red light, THEN stop the car.

Symbols game

The <, > and = symbols were covered in SILO 1.2 'Symbols'. The following game build on this knowledge in the context of coding and the concept of 'IF THEN'. Paper cards could be made but cardboard works better. The image below shows number cards and symbol cards. The numbers are between 1 and 100 but the symbols cards have = on one side and < on the other. Depending on the orientation of the < card it could be < or >. The game is played as follows:

• Each student is given a number card and a symbol card.
• Everyone stands in a circle facing each other holding the cards in front of their chest or stomach so everyone can see them clearly.
• The number card must go in the right hand and the symbol card in the left hand.
• Depending on the number, each student must arrange their symbol card so that the sequence is correct.
• The teacher starts by stating their number followed by their symbol. For example, "32 greater than".
• The pattern continues moving clockwise around the circle. For example, "12 less than", "60 less than", "91 greater than", "15 less than" and so on.
• Any errors in the symbol orientation should be fixed before moving on to the next person.
• When everyone in the circle has had their turn the students are given 5 seconds to shuffle into a new position in the circle but they must keep the same two cards.
• A new game then commences.
  

Symbol activity

For this activity everyone is going to get a number. Your task is to move through the classroom, stopping at each of the signs that have been put up around the room. These signs will consist of symbols we have learned so far in the unit (>, =, <). You are going to go through the conditional statement process we have outlined, first checking your number to see where it falls in relation to the symbol, then taking the action of moving to the correct side.

For example, if your number is a 6, and you come across a sign stating “< 9”, you are going to first check if this statement is true or not. Take a look at your number; if it is true that your number is < 9, move to the LEFT and check the next condition. Otherwise, move to the RIGHT. At the end of the game, we will see where each classmate ended up, and the path that they followed!

Binary numbers as code

Computer coding involves coding languages and, just like spoken language, there are many in use around the world. Computers and digital devices use binary code, where the two options are on and off. This is a little like when you used Morse code and there were just two options, dots and dashes. The on and off in binary code is commonly achieved using electrical pulses at 5 volts. The following image shows off as a black box and on as white. Each box is a 'binary digital' or bit. Eight bits together is a byte. As you can see below, each letter of our alphabet can be represented using eight bits.

Binary code chart

(Image source https://code.org/curriculum/course2/14/Teacher)

Binary bracelet activity

This binary bracelet activity involves giving each student a piece of paper with the following image.

• Ask each student to colour in the boxes to represent the first letter of their name as shown in the binary code chart above.
• The bracelet can then be attached to their wrist using tape, glue or a fastener such as a carefully placed staple.
• A printable A4 sheet with 10 binary bracelets is available by clicking here.

Moderated self-assessment

Discussions with students around the key components of conceptual topics and how they fit together can generate insights into student achievement.

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