Teaching Sequence

Work through this resource material in the following sequence:

20 minutes – Part A: Doing the Experiment
50+ minutes – Part B: Communicating the Results

Part A: Doing the Experiment

Step 1.

Collect all the components of your experiment:

Beakers
Eggs (hardboiled, at least two)
Acid
Fluoride rinse (optional)

Step 2.

Decide on the parameters of your experiment. Generally speaking, we want to explore how tooth decay can occur over time. The eggs will stand in for teeth, as the two have some similarities in their chemical composition (eggs are made from a calcium carbonate, while teeth are made from calcium phosphate). Due to this chemical similarity, the two can react in similar ways.

Whatever parameters you choose, the general expected outcome is that the eggs dipped in the fluoride mouthwash will hold up better against the acid. The actual parameters for your class are quite open. For instance, in the simplest approach, you could put one egg into a beaker of water, one egg into a beaker of acid, and then observe the difference over a period of days.

For a more complex experiment, you could dip one egg into fluoride mouthwash, and leave it for a day to soak. Then put both eggs into beakers of acid, and compare the difference over days.

Alternately, as a third variation, you could dip one egg in the fluoride mouthwash for a day, place both eggs into acid, and then re-dip the fluoride egg into the fluoride at certain intervals (say once a day for ten minutes). You could even multiply the eggs further, with different eggs dipped in fluoride mouthwash for different lengths of time or at different intervals.

Obviously if you want students to be handling eggs dipped in acid, you either need to be using a relatively weak acid, or you need appropriate lab safety protocols around handling the different materials. If you do not think that your students could sensibly and safely handle the materials, consider running the experiment as more of a demonstration. If you are confident running the experiment as a class exercise, you will also obviously need to gather a sufficient number of beakers and other materials.

Finally, in order to carry out the science-communication part of this lesson, it might be best to use a clear acid, so that students can visually document the state of the eggs with photographs or film. You may also need to carry out this experiment a week or so before starting the second part of the lesson, so that the eggs have time to dissolve and students have time to record the process.

If you are doing this science unit as a whole unit of work, we recommend doing this first part of the lesson at the start, proceeding through lessons 1-3 as per normal, and then completing the second half of this lesson, which draws on findings both from lessons 1-3 and on the recordings of the dissolving eggs.

Step 3.

As the experiment progresses, make sure your students are documenting the state of the eggs. They should be recording observations in writing, as well as visually documenting the state of the eggs with photographs or film.

Because students will use these visuals for the science communication project in Part B, spend some time thinking about how the beakers are positioned and dressed. Is there an environment or a set of props that would make for better photos? These sorts of questions will be explored in more depth with students in the second part of the lesson, but you should keep them in mind the whole way through, so that when students arrive at that part of the lesson, they’ll be well-positioned to carry out the learning. You might even want to explain the next stage of the lesson to students, so that they can be thinking about it when they dress and frame their photos.

Part B: Communicating the Results

We recommend carrying out this part of the lesson after you have carried out the eggs-periment in Part A. You may need to leave a few days for the eggs to dissolve properly. Make sure that you have documented the eggs dissolving, either through film or with photos.

Step 1.

If you have completed the previous lessons in this unit, have your students gather their reviews of those lessons. Alternately, if you have not completed those lessons, you might want to spend some time reviewing one of your previous lessons with students. Students should answer these three questions:

Which parts of the lesson do you feel you learnt the most from? Why?
Which parts of the lesson do you feel you learnt the least from? Why?
Which activities do you think would be the best for younger students?

Step 2.

Explain to students that in this part of the lesson, they will be carrying out a science communication project. They will be communicating to younger students about the value and use of fluoride mouthwash.

Step 3.

First, students should review and combine their notes from the previous lessons. They should pay particular attention to the questions that ran across the different lessons - the three outlined above. Were there any parts that they felt they consistently learnt better from? Which activities were regularly identified as good for younger students?

To share this thinking, students should carry out a scaled pairing. First, they should get into pairs, and within each pair decide which parts were a) the best for learning, b) the worst for learning, and c) most appropriate for younger students. Then, each pair should find another pair, and repeat the process: that is, each new, bigger group should weigh up the two opinions and pick one to carry forwards. Repeat the process until the whole class has come together as one big group to make a final decision on the most important facets of the lesson.

Step 4.

With those most important facets in mind, the class should develop a way of communicating their new science knowledge around tooth decay to younger students. They could create a poster, for instance, or a slideshow or something else. Whatever approach they choose should reflect the principles that they have decided on; that is, if they have decided that parroting science facts was a bad way to communicate information, they should avoid that practice in their own work.

The photos or filming that you have done around the dissolving of the egg(s) might serve as useful media for this exercise, depending on what sort of project your students decide to undertake. Students may even decide that they need to carry out further experiments, so that they can generate further footage or photos - this sort of work can be undertaken at your discretion, depending on the available time and resources.

Step 5.

Once students have completed their science communication piece, arrange to have it shown to your target younger group. You may need to arrange a visit with another teacher beforehand. We also recommend Year 7-8 students as an ideal group for this work, but it is really up to you.

Step 6.

During your visit to the younger students, ask your class to observe how the younger students react to the work that they produce. These observations may provide useful grist for a debriefing after the class - what did the younger students react well to? What did they like? What did they not like? How did these responses align (or not align) with your expectations going in? What have we learned about learning?

Teacher Reflection

Take this opportunity to reflect on your own teaching:

What did you learn about your teaching today?
What worked well?
What didn't work so well?
What would you share?
Where to next?
How are you going to get there?

SugarByHalf - Communicating the Science of Tooth Decay

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