Activity Introduction

Quick summary: In this activity students will experiment with the surface tension of water using pepper and dishwashing liquid.

These Snappy Science resources have been created to boost science education in primary schools across Australia. Each lesson is designed to support teachers with the scientific knowledge, ideas and resources to stimulate a sense of wonder and curiosity in their students. Many of the big issues that Australian society will face in the future are around technology, energy, resources and climate change. All of these require students to engage with science – but most of all to enjoy science!

Science at Home: These Snappy Science resources can also be used to engage families in fun science and learning for life. You can download a student friendly version of this activity here and you can also check out the Snappy Science Digital Library.

General capabilities: Critical and creative thinking.

Australian Curriculum content description: This activity is relevant to Science Inquiry Skills across all primary year levels of the Australian Curriculum.

Year 2 Science

  • Earth’s resources, including water, are used in a variety of ways (ACSSU032)

Year 5 Science

  • Solids, liquids and gases have different observable properties and behave in different ways (ACSSU077)

Syllabus OutcomesST1-9ES, ST2-7PW.

Time required: 10 – 15 minutes.

Resources required: Small bowl, ground pepper, dishwashing liquid, cocktail stick or toothpick, water.

Safety advice: None.

Keywords: Surface tension, dishwashing liquid, pepper.

Cool Australia’s curriculum team continually reviews and refines our resources to be in line with changes to the Australian Curriculum.


Teacher Worksheet

Brief summary:

In this activity you will experiment with the surface tension of water using pepper and dishwashing liquid.

Students can use the Predict, Observe, Explain table on the Student Worksheet to describe and reflect upon this experiment.

You will need:

  • Small bowl
  • Ground pepper
  • Dishwashing liquid
  • Cocktail stick or toothpick
  • Water

What to do:

Step 1. Half fill a small bowl with water.

Step 2. Sprinkle pepper on the surface of the water, forming a small layer.

Step 3. Dip your cocktail stick or toothpick into the washing-up liquid, then dip the tip of the stick in the middle of the water.

Step 4. As the washing-up liquid touches the water, watch what is happening to the pepper. The pepper should spread out and merge together forming patterns.

How does it work?

Surface tension basically means that there is a sort of skin on the surface of water where the water molecules hold on tight together. If the conditions are right, they can hold tight enough to suppo

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Student Worksheet

In this activity you will experiment with surface tension.


Explain what you think will happen:


Explain what happened:


Explain why you think this happened:

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