CS4HS – Computer Science Level 1 Introduction

1.44 Demonstrate understanding of basic concepts from computer science

PDF of standard

Golden rule of interface design is consistency.

  • Example – setting alarm on device
    • User – appointment
    • Task – setting the exact time

To learn about an interface, get students to get parents to use the interface. Think about who the audience and what the task really is. Think aloud cognitive walk through.

Have students using personal examples, different interfaces.

HUMAN COMPUTER INTERACTION – CS Field Guide

Problems when programmers haven’t looked at issue from users point of view – door example – green light means is secure / locked, users think it open so can go through.
Teller at Westpac with typing in amounts – inconsistent ways to input into different places in the system

ALGORITHMS

http://www.csfieldguide.org.nz/Algorithms.html

Phone book example

What is an algorithms? A way to solve a problem, a method to solve a problem

AS – describing key characteristics and roles of algorithms, program and informal instructions
CS Field Guide – 2.1.1. ALGORITHMS, PROGRAMS AND INFORMAL INSTRUCTIONS

Ripping phone book in half, then half again – binary search. But data has to be sorted if using a binary search.

Algorithms have an associated cost. Different ways to measure cost – cost is often time.

Comparisons – weight example. Selection sort: 9 items – 8 comparisons.

What an algorithm is and what the cost is? Best way is comparison. Students do not need to write the program, they just need to run it (see guide – 2.3. SORTING ALGORITHMS). Important for students to do it with numerous different inputs / sizes – e.g. 1, 100, 1000 etc etc.

Quick sort – easier to do with your hands with objects. Weight example again – use one weight where you compare all others and put into two piles. 19 comparisons instead of 36 (selection sort) 2.3.4. QUICKSORT CS Field Guide

Demonstrate how an algorithm works, can put in photos or screenshots of scales on CS Field Guide. Good to use the programmes – python or scratch, can download from CS Field Guide.

Algorithms, interfaces and programming languages – 40 / 40 / 20 of how much students needs to do on each.

Programming – difference between compiling a programme and running a programme.

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