Searching: One by One or Cut in Half
Python Programming 2 Grades 9–12 5-day lesson 33 deliverables Teach students to write linear and binary searches in Python and compare how many steps each one takes. Students play a search game and a number guessing game, find best and worst cases and write a search that returns an index and a step count. They trace a binary search on sorted book codes, then race both searches on the same list.
● Instant download · Lifetime access · Editable & print-ready
Print + digitalPDF, PowerPoint, Word & Google
Answer keysA key for every page
Built-in assessmentExit tickets + lesson quiz
45-minute daysEvery day planned and timed
Short coding levels practice this lesson in CodeGrove, our code lab that runs in the browser. Students write the program, run it and check it, with no account and nothing to install. Use them with the lesson or as practice later.
See the levelsWhat does this lesson cover?
Students often put return -1 inside the loop, so the search quits after one item, or they forget that binary search needs a sorted list. This lesson places return -1 after the loop and counts the steps of each search so the difference is clear.
The try-it on Day 1, the labs on Days 2 and 4 and the quiz task on Day 5 run online in CodeGrove, our in-browser code lab, so students need a computer or tablet on those days. The Lost and Found and Shelf Finder levels practice writing a linear search and a binary search that count their steps, then racing them on the same list. CodeGrove is free, with no accounts, sign-ins or installs.
Lost and Found
Students write a linear search that counts its steps and a search that finds every match, in CodeGrove.
Everything that's included
00 Start Here
- READ FIRST: every file in the lesson and when you use it
- Teacher Guide and Pacing: the plan for each day, what to print and how to grade
- Skills map: which standards each day teaches
01 Present
- One editable PowerPoint deck for all five days, 37 slides, with speaker notes
- Slide script: the speaker notes, printed
- Bell ringers: a short warm-up for each day
02 Student Handouts
- Guided notes: one packet for all five days, in PDF and editable Word. Students fill in the blanks during the slides, with the word bank on the page
- Vocab slip: the lesson's words and what they mean, on one page
03 Labs
- Lost and Found: students write a linear search that counts its steps and a search that finds every match, in CodeGrove
- Shelf Finder: students write a binary search that counts its steps and race it against a linear search, in CodeGrove
04 Activities
- Find It by Hand: students play a search game on paper with computers closed and find the best and worst cases
- Guess My Number: students trace a binary search on paper with computers closed, in a number game and on a sorted list of book codes
- Quiz task: students fix a binary search in CodeGrove, working alone, and then take the lesson quiz on paper
05 Assessment
- Exit tickets: quick questions that show who needs more help
- Lesson quiz: 8 multiple-choice questions and 2 written answers about all five days, on paper
06 Answer Keys
- 7 answer key files: a key for each day (its bell ringer, notes and exit ticket) and the activity and lab keys, plus the quiz key
Digital: Google Forms™ + Google Slides™
- 6 Google Forms™ of the exit tickets and the quiz, ready to copy into your Drive
- The multiple choice grades itself, and you grade the written answers
- A Google Slides™ copy of the deck, with the same slides and speaker notes, for Google Classroom™
- Give a Form that asks students to read code only on school-managed Chromebooks in locked mode, and use the paper version on other devices
Online: CodeGrove
- In CodeGrove: the labs on Days 2 and 4 (Lost and Found and Shelf Finder) and the quiz task on Day 5, on a computer or tablet for each student
- A try-it on Day 1: students practice the new code in CodeGrove, and nothing is turned in
- Free to use, with no accounts, sign-ins or installs
Why teachers love this lesson
Counting steps makes the difference clearStudents count the steps of a linear search and race it against a binary search on a long sorted list.
Binary search needs a sorted listStudents trace low, mid and high on paper and use // to find mid, because a list index must be a whole number.
Print and digitalEvery page is a print-ready PDF, and the Google Forms™ and Google Slides™ let you teach the same lesson in Google Classroom™.
Real online labsStudents write and run real Python in CodeGrove, our in-browser code lab, on a computer or tablet, with no accounts or installs.
A key for every pageEvery day has its own answer key, and every written question has a sample answer and what to look for.
Every day fits a 45-minute classEach day's plan is timed activity by activity against real reading and writing speeds.
What Teachers Say
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How do I get the files after I buy?
Instant download right after checkout: PowerPoint and Word files you can edit, print-ready PDFs, and links that copy the Google Forms™ and Google Slides™ into your Drive.
Can I buy the whole unit or course instead?
Yes. This lesson is part of the Unit 6 bundle and the complete Python Programming 2 course. Both cost less than buying the lessons one at a time.
Is this AP Computer Science?
No. It is a full-year, non-AP second course in Python for grades 9 to 12. For AP, see our AP Computer Science A and AP CSP courses.
What should students know before this lesson?
Students know how to write a function that returns a value, sort a list with .sort(), and use len() and indexes.
Do students need computers?
Yes, on the CodeGrove days. Each student needs a computer or tablet that's online, and CodeGrove needs no account or install. The bell ringers, notes, exit tickets and quiz are on paper.
What formats are the files in?
Every page is a print-ready PDF. The slides are an editable PowerPoint and the guided notes an editable Word file. The exit tickets and the quiz also come as Google Forms™, and the deck as Google Slides™.
Which standards does it cover?
Written for Florida's Intermediate Programming course (9007220). The skills map in the lesson shows which standards each day teaches.