Science · Year 4

Active learning ideas

Tooth Decay and Oral Hygiene

Uncover the science behind every smile and explore the battle that happens in our mouths every day.

• National Curriculum Attainment Targets
• National Curriculum for England: Science Year 4: Animals, including humans

• 30–60 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Experiential Learning
• 45 min · Small Groups

The Eggshell Decay Experiment

Hard-boil several eggs and place them in different liquids like cola, orange juice, water, and milk. Observe the eggs over several days to see how the acidic and sugary drinks stain and weaken the eggshell, which acts as a model for tooth enamel.

Explain how sugary foods and drinks can cause tooth decay.

Facilitation Tip

Ensure pupils record their initial predictions and daily observations to practise scientific recording.

What to look for

Use an exit ticket where pupils must write down one cause of tooth decay and one way to prevent it before leaving the lesson.

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Activity 02

• Experiential Learning
• 30 min · Individual

Plaque Attack!

Use plaque-disclosing tablets (with parental consent) to show pupils the invisible plaque on their teeth. After chewing the tablet, the plaque is stained a bright colour, revealing the areas they miss when brushing, followed by a session on correct brushing technique.

Identify three key actions for maintaining healthy teeth.

Facilitation Tip

Have mirrors available for each pupil to clearly see the results in their own mouths.

What to look for

Pupils complete a labelled diagram of a tooth, indicating where enamel is and how decay can form. They could also write a short paragraph explaining the process.

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

Activity 03

• Experiential Learning
• 60 min · Small Groups

Healthy Smile Campaign

In groups, pupils design a poster or a short presentation aimed at younger children. The campaign should explain the causes of tooth decay and give three simple rules for keeping teeth healthy.

Justify the importance of brushing your teeth twice a day.

Facilitation Tip

Provide a clear brief with key information that must be included, such as the role of sugar and the importance of brushing.

What to look for

Pupils use a simple checklist to reflect on their own weekly oral hygiene habits, such as brushing twice a day and limiting sugary snacks.

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

A few notes on teaching this unit

Begin by exploring pupils' prior knowledge about teeth and their function. Use visual aids like large tooth models to demonstrate brushing techniques effectively. A hands-on experiment, such as observing eggshells in different liquids, provides a powerful and memorable analogy for the abstract process of enamel decay.

Pupils will be able to explain the cause of tooth decay and confidently describe the actions needed to keep their teeth and gums healthy for life.

---

Watch Out for These Misconceptions

• Sugar itself directly rots your teeth.

  It is not the sugar itself, but the acid produced by bacteria in your mouth when they eat the sugar. This acid is what dissolves the tooth's protective enamel.

• Fruit juice is healthy, so it must be good for my teeth.

  While fruit contains vitamins, fruit juice is very high in sugar and acid. Both of these can cause significant tooth decay, so it should be consumed in moderation and preferably with a meal.

• Baby teeth don't matter because they fall out anyway.

  Baby teeth are very important. They help children chew food properly, speak clearly, and hold the correct space in the gums for the adult teeth to grow into.

• You only need to brush the front teeth that people can see.

  It is crucial to brush all surfaces of every tooth, including the back, front, and chewing surfaces, as plaque builds up everywhere.

---

Methods used in this brief

• Experiential Learning