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Acids, Bases & the pH Scale

Students explore acids and bases — from lemon juice to bleach — and the pH scale that measures them, learning what makes a substance acidic or basic and why the scale runs from 0 to 14.

Grade 10Acids & Bases55 minutes1 class period5E ModelExplicit teaching4 StandardsCommon Core
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Lesson at a Glance

Everything you need before the bell rings

Learning Objectives

Students will be able to…

  • ✓Define acids and bases.
  • ✓Read the pH scale.
  • ✓Classify substances by pH.
  • ✓Explain neutralization.
Essential Question

Lemon juice, soap, water, and bleach — what invisible property separates them, and how can one scale from 0 to 14 capture it?

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Lesson Phases
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Vocabulary Terms
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Standards Aligned
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Interactive Task
pH Scale · Interactive

The pH Scale

Project this and slide across the pH scale. Watch the color, category, and a real example change from strong acid to strong base.

🧪 Slide the pH scale — acid, neutral, or base?Try it
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The Lesson · 5E Model

55 minutes, five moves

Tap any phase to open the teacher moves and student actions.

1

Engage — One Hidden Property

5 min

Lemon juice vs. soap — what invisible property differs?

👩‍🏫 Teacher Moves

  • Compare familiar substances.
  • Ask what separates them.
  • Set the goal: acids and bases.

🎒 Student Actions

  • Compare substances.
  • Wonder what differs.
  • Predict the idea.
2

Explore — Explore the Scale

12 min

Students investigate.

👩‍🏫 Teacher Moves

  • Send students to the pH Scale.
  • Slide across 0–14.
  • Classify substances.

🎒 Student Actions

  • Slide the scale.
  • Read categories.
  • Classify examples.
3

Explain — Acids, Bases & pH

13 min

Teacher explains.

👩‍🏫 Teacher Moves

  • Define acids (H⁺) and bases (OH⁻).
  • Explain the 0–14 scale.
  • Explain neutral (pH 7).

🎒 Student Actions

  • Explain acids.
  • Explain bases.
  • Explain neutral.
4

Elaborate — Elaborate — Test & Neutralize

12 min

Apply.

👩‍🏫 Teacher Moves

  • Test substances with indicators.
  • Explain neutralization.
  • Predict a mixture’s pH.

🎒 Student Actions

  • Test substances.
  • Explain neutralizing.
  • Predict pH.
5

Evaluate — Evaluate — Exit Ticket

5 min

Three quick checks.

👩‍🏫 Teacher Moves

  • Hand out the exit ticket.
  • Look for pH reasoning.
  • Collect as formative data.

🎒 Student Actions

  • Classify a pH.
  • Explain the scale.
  • Define neutral.
Standards Alignment

Built to the standards you report on

Aligned to the Next Generation Science Standards (High School Chemistry) and Common Core literacy in science.

NGSS
HS-PS1-2

Construct an explanation for the outcome of a reaction based on patterns.

NGSS
HS-PS1-5

Apply scientific principles to explain reaction rates and factors.

NGSS
HS-PS1-6

Refine a design to favor products in a chemical system.

CCSS
RST.9-10.7

Translate quantitative information into a visual model.

Differentiation

One lesson, every learner

Multilingual Learners

ELL / EMERGING READERS
  • pH color-scale reference.
  • Sentence frame: “pH ___ is ___.”
  • Test real substances.

Support & Access

IEP / 504
  • Focus on acid/neutral/base.
  • Use a color pH strip.
  • Classify clear examples.

Stretch & Extend

GIFTED / EARLY FINISHERS
  • Explain the logarithmic scale.
  • Investigate neutralization reactions.
  • Test household substances.
Materials

What to gather

  • 📽️Projector / board
  • 📓Science notebooks
  • 💻The pH Scale
  • 🧪pH strips + samples
  • ✏️Pencils
  • 🎫Exit-ticket slips
Vocabulary

Key terms — hover for a quick definition

acida substance with pH below 7 (donates H⁺)basea substance with pH above 7 (accepts H⁺)pH scalea 0–14 measure of acidityneutralpH 7, neither acid nor baseindicatora substance that changes color by pHalkalineanother word for basicneutralizationan acid and base reacting to cancel outcorrosiveable to damage materials/skin
Evaluate

Exit Ticket

Preview the three formative checks. Tap “Sample answer” to see what mastery looks like — hide them before you print for students.

QUESTION 1
What does a pH of 7 mean?
The substance is neutral (like pure water) — neither acidic nor basic.
QUESTION 2
Is a substance with pH 3 an acid or a base?
An acid (below 7).
QUESTION 3
What happens when you mix an acid and a base?
They neutralize each other, moving the pH toward 7 (and often forming water and a salt).

Going deeper? Why 10× per step?

Have students explore why the pH scale is logarithmic — each whole step is a tenfold change in acidity — and test household substances. A printable pH lab sheet is in the Science library.

Study · Flashcards

Study the key terms

Tap a card to flip it, then rate whether you knew it. Built from this lesson’s vocabulary.

🃏 Acids, Bases & pHFlip
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Practice · Quiz

Check your understanding

A quick self-check with instant feedback, drawn from this lesson’s key terms.

📝 Acids, Bases & pHQuiz
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Question 1
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Practice · Worksheet

Printable worksheet

A print-and-go review sheet with a built-in answer key. Tap “Show answer key” to reveal answers, or print the clean version for students.

🖨️ Acids, Bases & pHPrint
Name: ________________________
Date: ____________

Part A · Write the word that matches each meaning

Word bank: acid, alkaline, base, corrosive, indicator, neutral, neutralization, pH scale
  1. a substance with pH below 7 (donates H⁺)
  2. another word for basic
  3. an acid and base reacting to cancel out
  4. able to damage materials/skin
  5. a substance that changes color by pH
  6. a 0–14 measure of acidity
  7. a substance with pH above 7 (accepts H⁺)
  8. pH 7, neither acid nor base

Part B · Show what you learned

  1. What does a pH of 7 mean?
  2. Is a substance with pH 3 an acid or a base?
  3. What happens when you mix an acid and a base?
Answer key — Part A: 1) acid · 2) alkaline · 3) neutralization · 4) corrosive · 5) indicator · 6) pH scale · 7) base · 8) neutral
Part B: 1) The substance is neutral (like pure water) — neither acidic nor basic. 2) An acid (below 7). 3) They neutralize each other, moving the pH toward 7 (and often forming water and a salt).