The lesson plan, then the notes for every slide. Print on A4 and take the second sheet to the board.

The Whole Bite Club · Year 5 and Year 6 · Lesson 4 · After the visit

The pH of the drinks aisle

Students meet the number that decides whether a drink softens enamel, then meet a real Australian data set of 177 drinks. The finding that lands hardest is that removing the sugar does not remove the acid: a zero-sugar cola sits in the same erosive band as the full-sugar one. Students handle, compare and represent the data, which is Year 6 statistics as much as it is health.

Learning intention

In this lesson, we will find out what pH 5.5 means for a tooth, and test the idea that sugar-free means tooth-friendly.

Success criteria

I will know I am successful when I can:

I can explain what happens to enamel below about pH 5.5.
I can compare two sets of drink pH values and describe them using range and mode.
I can evaluate the claim "sugar-free is better for your teeth" and say which part of it is true.
I can plot eight drinks on a pH scale and write one sentence explaining the sugar-free result to a Year 3 student.

Guiding questions

Two colas. One has 16 teaspoons of sugar and one has none. Which is worse for your enamel?
Is a sports drink a drink, or a piece of equipment?
If almost nothing on the shelf is above the line, what is the line actually telling you?

Vocabulary

pH · critical pH · erosive · range · mode · sample

Australian Curriculum

AC9HP6P09

Support

Give the pH scale as a printed strip with 5.5 already ruled, and have students place drink cards on it rather than read a table. Give the sentence as a two-part frame.

Challenge

Measure three drinks with strips or a probe, compare with the published values and account for the difference. The paper notes drinks tested warmer read lower, which is a real and satisfying explanation.

EAL/D

pH is a symbol before it is a word; introduce it as a number on a scale with no etymology.
The "wrong side of the line" is idiomatic and gets replaced on the sheet with "below the line". Sentence frames for the Year 3 explanation.

Disability

The scale is available at A3 and as a large-print version with the eight values pre-plotted for students to label rather than draw.
Strips are read in pairs so no student is required to make a fine colour judgement alone, and any colour matching has a printed number scale beside it.

Exit ticket

Below what pH does enamel start to dissolve?
A drink is advertised as having no sugar. Name one thing you would still want to know about it, and say why.

Assessment of learning

The explanatory sentence written for a younger reader is the assessable piece, because simplifying without breaking the idea requires holding it firmly.

Rubric line

Uses evidence to evaluate a health claim.

Working towards

states that sugar-free drinks can still harm teeth

At standard

states that and explains it with both halves, no sugar for the bacteria and acid that dissolves enamel on its own

Above

does that and cites a value from the data set to support it

Inclusion notes

No student's own drink bottle is measured, displayed or discussed.
Say once that this lesson is about what is in a drink and never about who drinks it.
Do not connect any drink to weight, body size or appearance; the sugar and obesity link is real and is not this unit's subject.

Resources

Years 3 – 6 Supporting Resource Pack
Printed Above the line, below the line sheet, A4 landscape, plus an A3 large-print version with the eight values pre-plotted for labelling
pH strips or a pH probe, one set per group; strips read in pairs so no student makes a fine colour judgement alone, with a printed number scale beside any colour chart
Five drinks for the measuring task, poured into unlabelled cups by the teacher; no student's own bottle is used
The printed pH scale strip with 5.5 already ruled, for the support version
The data-source attribution card for Schmidt and Huang

Worksheets to print

Above the line, below the line · /downloads/5-6/above-the-line.pdf
Lesson 4: The pH of the drinks aisle (PowerPoint) · /downloads/decks/5-6/04-ph-of-the-drinks-aisle-slides.pptx

The pH of the drinks aisle · handout for the whiteboard

Teacher notes, slide by slide

The number beside each note is the slide it belongs to, counting from the first.

1.TitleThe pH of the drinks aisle
Today we find out what pH 5.5 means for a tooth, and test the idea that sugar-free means tooth-friendly.
2.Success criteriaYou will know you can do it when:
The fourth is the assessed product.
3.QuestionTwo colas. One has 16 teaspoons of sugar, one has none. Which is worse for your enamel?
Take positions and record the split. Most classes vote for the sugary one.
4.PicturepH is a measurement
The tooth stands on the line. Everything left of it is below.
5.SlidepH is a measurement
Stop there. No ions, no chemistry. The ADA puts acid-base theory at Years 9–10 and this band takes the measurement only.
6.SlideThe line at 5.5
Say "about". The exact figure varies with the calcium and phosphate in a person's saliva.
7.GameBelow 5.5
Predict before every reveal. The full-sugar cola and its no-sugar twin come back to back; that is the design.
8.SlideThe study
Method, sample size and date all stated. Point that out: this is what a checkable source looks like, which is lesson 5.
9.Data tableWhat they found
Read bottled water last. Sparkling water and juice will surprise the class, which is why the prediction came first. Three things to say once: sports drinks are given as a middle value because their readings were not evenly spread; the juice range is blank because the study's summary table and its detail table disagree on it; and the nine counts add to 178 against a stated 177, which is how you find a slip in a good source — by adding the column up.
10.PictureThe pair that settles it
The same two glasses the class voted on. Now read the two numbers.
11.SlideThe pair that settles it
Removing the sugar removes the fuel for decay and does nothing about erosion. Go back to slide 3's vote here.
12.SlideOnly 11 out of 177
Let the arithmetic do the work. No moralising and no drink is called bad. The third bullet is checkable in the study's own Table 1, and it lands harder than the abstract phrase it replaces.
13.QuestionIs a sports drink a drink, or a piece of equipment?
Genuine contest. Say the endurance framing as ours, not as the ADA's: sports drinks are built for prolonged endurance exercise, and for an hour of school sport water does the job. Re-fetched ADA Policy 2.2.2 does not name sports or energy drinks at all; what it supports is the general caution against frequent consumption of drinks high in sugar or acid.
14.SlideWater
The split is deliberate. The first two lines are true everywhere; the third is not, and about 72% of Queenslanders have treated water.
15.WorksheetAbove the line, below the line
Seven of the eight sit below the line. The sentence needs both halves to be right.
16.Exit ticketBelow what pH does enamel start to dissolve?
The two questions from Lesson.exitTicket. The application question is the whole lesson, and it is the bridge into lesson 5.
17.RecapWhat we found out
Then ask: what is in your drink bottle tomorrow?

Where this comes from

Policy Statement 2.2.2 - Diet and Nutrition · Australian Dental Association · Opened 5 September 2026. That drinks and foods high in sugar or acid are a sometimes choice for children, and that sugar and acid together are the harder pair on teeth. https://ada.org.au/policy-statement-2-2-2-diet-nutrition
Dental erosion · Better Health Channel · Opened 5 September 2026. That acid alone wears enamel away with no germs involved, which is why a sugar-free soft drink is still hard on teeth, and the advice to wait about half an hour after something acidic before brushing. https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/dental-erosion
The majority of Queensland councils are washing their hands of fluoridation under the watch of both sides of politics · ABC News · Opened 5 September 2026. Why the lessons say tap water helps protect teeth in many places rather than everywhere: about 72 per cent of Queenslanders have a treated supply, and most councils have stopped treating. https://www.abc.net.au/news/2025-09-27/qld-fluoride-water-supply-tooth-decay-politics-washing-hands/105820504
The Acidity of Non-alcoholic Beverages in Australia: Risk of Dental Erosion · Jeremiah Schmidt and Boyen Huang, International Journal of Scientific Study, volume 8 issue 2, May 2020 · Opened 5 September 2026 · PDF. The acidity readings behind the drinks data set. The paper's Materials and Methods section is where the method sits: 177 drinks sold in Australia, each measured three times at 22 °C, with dairy drinks left out. The journal lists it as item 8 of the May 2020 issue. https://www.ijss-sn.com/uploads/2/0/1/5/20153321/08_ijss_may_oa01_-_2020.pdf
Dental erosion · healthdirect Australia · Opened 5 September 2026. Two things. How long enamel stays soft after acid — the page puts it at 20 to 30 minutes, and the class is taught the 20 the clinicians ruled on. And which drinks are acidic enough to wear enamel away, sugar-free soft drinks among them, with the food acids a student reads off a label listed in its own sentence further up the same page: "foods with additives — such as citric acid, sodium citrate or phosphoric acid". It is the national service saying independently what the acidity paper measured. https://www.healthdirect.gov.au/dental-erosion