What CSS Does
Computer Science Fundamentals Grades 9–12 3-day lesson 26 deliverables This computer science lesson shows students how a single CSS style sheet gives every page of a website the same look. Students study Cherry Street Bookstore's pages, work out which pages change when one rule changes, and explain why one style sheet helps.
● 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
A short browser game practices this lesson with new examples. Students play on a computer or tablet, with no account and nothing to install. Use it with the lesson or instead of the paper activity.
Play itWhat does this lesson cover?
Students often think each page needs its own copy of the CSS, or that a missing semicolon only breaks one line. This lesson shows them how a single style sheet reaches every page and how one small typo can break much more than a line. Students practice reading a rule before they write one, so they can find and fix their own mistakes.
The lab on Day 2 has an online version that uses Web Lab, our online game, in the One Rule, Many Places level. It practices fixing and changing CSS rules so one rule styles every matching tag. Every online version comes with a paper version, so no internet is needed. Our game is free, with no accounts or sign-ins.
One Rule, Many Places
Students fix four pages' CSS or link tags and write each fix and what changes, on paper or in the Web Lab.
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 three days, 28 slides, with speaker notes
- Slide script: the speaker notes, printed
- Bell ringers: a short warm-up for each day
02 Student Handouts
- Guided notes for all three days, in PDF and editable Word, with the word bank on the page
- Vocab slip: the lesson's words and what they mean, on one page
03 Labs
- One Rule, Many Places: fix four pages' CSS or link tags and write each fix and what changes, on paper or in the Web Lab
04 Activities
- Explain the Style: circle which pages change when the bookstore's style sheet changes, then explain how one style sheet helps
- Fix the Style: find and fix a broken rule in the bookstore's new style sheet on paper
05 Assessment
- Exit tickets, one per day: quick questions that show who needs more help
- Lesson quiz: 10 multiple-choice questions and 2 written answers about all three days
06 Answer Keys
- 5 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™
- 4 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™
Online: Web Lab
- Web Lab, One Rule, Many Places level: the online version of the Day 2 lab
- Every online version has a paper version, so no internet is needed
- Free to play, with no accounts or sign-ins
Why teachers love this lesson
Students see the cascade at workThey learn what the browser does when rules disagree, so they can predict how a page will look before they check it.
The broken pages have real mistakesStudents fix the errors new coders often make, like a missing semicolon, a typo or a broken link tag.
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 activitiesStudents can use Web Lab on a computer or tablet, and every online version has a paper version that works with no internet.
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 7 bundle and the complete Computer Science Fundamentals 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 intro course for grades 9 to 12. For AP, see AP Computer Science Principles and AP Computer Science A.
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 Advanced Information Technology course (9007610). The skills map in the lesson shows which standards each day teaches.