Science Lesson Kit · Teacher Resource
Acids & Bases: Properties, Indicators & pH — 5E Lesson Plan
Physical Science · 50 minutes
Grade 5
5E lesson flow
01
Engage
6 min
Teacher Does
Show three clear teacher-approved samples and ask whether appearance is enough to classify them.
Students Do
Predict what evidence would be needed.
Ask
- What safe test could reveal a hidden property?
Look For
Indicator or pH evidence rather than taste or touch.
02
Explore
14 min
Teacher Does
Model adding the same indicator amount to equal sample volumes.
Students Do
Observe and record color changes.
Ask
- What must stay the same for a useful comparison?
Look For
Equal sample volume and indicator amount.
03
Explain
10 min
Teacher Does
Connect indicator references to acid, neutral, base, and pH.
Students Do
Classify sample evidence and justify it.
Ask
- Where is neutral on the pH scale?
Look For
Below 7 acidic, 7 neutral, above 7 basic.
04
Analyze
10 min
Teacher Does
Provide new pH and indicator evidence cards.
Students Do
Compare cases and identify claims that exceed the evidence.
Ask
- What can this test tell us, and what can it not tell us?
Look For
Classification without claiming safety from pH alone.
05
Apply
6 min
Teacher Does
Present a flawed comparison using different indicator amounts.
Students Do
Repair the fair-test plan.
Ask
- What condition should be controlled?
Look For
Consistent indicator and sample amounts.
06
Evaluate
4 min
Teacher Does
Give one new pH value.
Students Do
Classify it and explain with the scale.
Ask
- What evidence supports your classification?
Look For
Correct scale reasoning.
Student goal
I can use safe indicator and pH evidence to classify solutions and explain my reasoning.
Learning objectives
- Use indicator color changes as evidence to classify safe solutions as acidic, neutral, or basic.
- Interpret pH values as a scale from acidic through neutral to basic.
- Plan a fair comparison that keeps indicator amount and sample volume consistent.
Materials
- Teacher-approved dilute classroom samples
- Prepared indicator such as red-cabbage indicator or commercial classroom pH indicator
- Clear sample cups
- Droppers
- Safety goggles
- White testing tray
- Reference color card without answers printed on student images
Before class
- Use only teacher-approved dilute samples.
- Do not allow tasting or skin testing.
- Prepare equal sample volumes.
- Set one indicator amount for all comparisons.
- Review disposal and spill procedures for the selected classroom materials.
Prior knowledge
- Students can measure equal liquid volumes with simple classroom tools.
- Students know matter has observable and measurable properties.
Vocabulary
- acid
- A substance that produces acidic properties in water and has a pH below 7.
- base
- A substance that produces basic properties in water and has a pH above 7.
- neutral
- Neither acidic nor basic; pure water is near pH 7.
- indicator
- A material that changes color in response to acidic or basic conditions.
- pH
- A scale used to describe how acidic or basic a water-based solution is.
- evidence
- Observations or measurements used to support a scientific claim.
Differentiation
- Provide a three-zone pH reference: below 7, 7, above 7.
- Use sentence frames: The sample is ___ because the evidence shows ___.
- Allow color-card matching before written explanation.
- For extension, compare two acidic pH values while avoiding unsupported claims about safety or taste.
Assessment
- Check acid/neutral/base classification.
- Check consistent fair-test conditions.
- Check that students use safe evidence and do not infer safety from pH alone.
Exit ticket
A sample has pH 9. What classification is supported, and why?
Extension
Design an indicator comparison that would produce evidence for three unknown teacher-approved samples.