Teaching Computer Science: Day 6 - Core Blimey!

In my sixth lesson, I decided to revisit the CPU however, this time, explore the three Cs: “Clock speed”, “Cache” size and number of “Cores”.

Learning Objectives:

• Describe cache memory
  
• Explain how common characteristics of CPUs such as clock speed, cache size and number of cores affect their performance

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Lesson 1: The 3 Cs

Suggested time: 50 mins

Starter:


I started with an activity adapted from a resource I found on CAS courtesy of John Bilton (johnbiltoncomputing.blogspot.co.uk) – “CPU Dart Activity”. You can find the original here: CPU Dart Activity

For those new to DART (Directed Activity Related to Text), this activity is designed to support literacy. It focuses on the strategies of skimming, scanning and gap fill. The purpose of this DART activity is to give the students a brief overview of the main features of the CPU.

Instructions:

1. Set up the presentation to suit the reading ability of your class (see PowerPoint presentation)
2. Print the key words slide and cut out the words. You could tape them to the underneath of chairs for random distribution if you wanted. (I fold the keywords into little pieces and place them in a small tin or bag for the students to pick)
3. Run the presentation so that students skim and scan the text. This is a way of engaging students with the kind of text they would find in a textbook, but without the textbook!
4. Selected students take turns come to the front to draw their key word whilst others try to guess it. I tend to split the students into teams and turn it into a competition. For a bit of fun, you could also use a timer (See blog on classroom timers) and give the opposing teams a chance to steal the points if the player’s team doesn’t guess right within a minute.
5. Follow up with the gap fill exercise.

cpu_dart_activity.pptx
File Size:	596 kb
File Type:	pptx

Download File

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Main Task:

I started by explaining the main three features to consider when purchasing a  CPU: Clock speed, Cache size and number of Cores. I then showed them a video courtesy of Mark Clarkson - "Mr. Clarkson talks about… The CPU" http://www.youtube.com/watch?v=P4QmPFcBELE (Skip to 6m14s)

I followed this by directing the students to wikispaces.com and instructed them to create a new page in their revision wiki called CPU. I then asked them to complete the following task:

1.    Write a definition for the following terms:

• Core
• Cache
• Clock Speed
  

2.    Explain what is meant by Multi-Core processors.

3.    Explain why a computer with a 4Ghz (6MB cache) processor would not be twice as fast as a 2Ghz (6MB cache) processor.


Resources:

Students can use the following links to help them complete their task:

Mr. Clarkson talks about… The CPU: http://www.youtube.com/watch?v=P4QmPFcBELE

Teach-ICT – CPU: http://www.teach-ict.com/gcse_new/computer%20systems/cpu/miniweb/index.htm

PWN ICT: http://www.pwnict.co.uk/computingGCSE/computingResources.html (Click on Hardware and then CPU)

Plenary:

Select students at random (See blog on random name selectors) to explain what is meant by Clock speed, Cache size and number of Cores. I tend to use Pose, Pause, Pounce and Bounce.

Example:

Pose a question to the whole class e.g. Explain why a computer with a 4Ghz (6MB cache) processor would not be twice as fast as a 2Ghz (6MB cache) processor.

Pause to give students time to digest the question and think of their answer. If the students are engaged, try holding the pause for a little while longer to build up the tension.

Pounce: Quickly, select a student to answer the question. i.e. Insist the answer to the question comes from student A and possibly student B, directly and fast! Obviously, plan in your mind who you are going to direct the questions to before hand.

Bounce the question or student's response on to another student (immediately after the pounce). e.g. Ask them if they agree with the students previous answer and to explain why.

For more information about the Pose, Pause, Pounce and Bounce technique, visit: @teachertoolkit - http://teachertoolkit.me/2013/01/04/pppb-version2/   

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Lesson 2: TouchDevelop Challenge

Suggested time: 50 mins

Main task:

Following on from the previous week’s lesson, I asked students to load TouchDevelop (www.touchdevelop.com) on their computers and sign in with their google, microsoft or yahoo id.

Once logged in, I sent them to the TouchDevelop Challenge (www.touchdevelop.weebly.com) and ask them to click on TD Challenge and attempt lesson 3 and 4. (touchdevelop.weebly.com/td-challenge.html).

Plenary:

To finish the lesson, I asked the students to swap seats and invited them to try out each other’s games - giving feedback where appropriate.