Welcome! This tutorial has been created to help educators confidently deliver the Geology of Petroglyphs activity in their classroom or learning environment OR for you to make your own petroglyph at home!

This activity explores geology through First Nations perspectives, examining how rocks are formed and the many ways Aboriginal and Torres Strait Islander peoples have used them for tools, art, shelter and cultural practices.

As part of the activity, learners design and carve a symbolic petroglyph using plaster, connecting geological concepts with deep - time histories and living cultures.

The video below will guide you through the activity, explain the materials you'll need, and demonstrate each step so you can prepare, make and design your own petroglyph with confidence!

Watch the tutorial above to get started.

Materials You'll Need

Before beginning the activity, gather the following materials:

Petri dishes (one per learner if with a class)
800 g Plaster of Paris
5 g Red Oxide
400 mL water (for the plaster mixture)
200 mL water (for removing air bubbles)
Sponge
Tablespoon measure
Whisk
Measuring cup
Mixing container

This recipe will produce approximately 12 - 14 petroglyph - ready 90 mm Petri dishes. Adjust the quantities as needed to suit the number of learners participating.

Before You Begin

We recommend watching the tutorial in full before facilitating the activity.

Preparing the materials in advance and allowing the plaster to fully set before carving will help ensure the activity runs smoothly and provide the best experience for learners.

Preparing the Petroglyph Bases

Prepare the plaster bases several days before your learning session to allow sufficient time for the plaster to fully cure.

Step 1: Gather Your Materials
Before you begin, ensure you have all the required materials ready, including your Petri dishes, Plaster of Paris, red oxide, water, mixing container, whisk, measuring equipment, and sponge.

Step 2: Prepare the Base Layer
Mix the required amount of Plaster of Paris with water according to the recipe provided.

Pour the white plaster mixture into each Petri dish to create an even base layer (approximately 7 mm deep). Gently tap each Petri dish on the bench to help release trapped air bubbles.

Allow the plaster to fully set before continuing. For best results, prepare this layer at least a couple of days before your learning session.

Step 3: Remove Surface Air Bubbles
Once the base layer has hardened, check for any air bubbles or imperfections on the surface.

Wet a clean sponge and gently wipe or pour a small amount of water over the plaster surface. This helps release any remaining trapped air and creates a smoother surface for the red layer.

Step 4: Prepare the Red Layer
Mix the remaining Plaster of Paris with water and add 5 g (about a tablespoon) of red oxide. Whisk thoroughly until the red oxide is evenly distributed throughout the mixture.

Step 5: Pour the Red Layer
Carefully pour the red plaster mixture over the white base layer, creating a smooth, even surface.

Aim for a thin top layer of approximately 2 mm. Learners will carve through this red layer to reveal the white plaster beneath, creating the petroglyph effect.

Step 6: Allow to Cure
Leave the Petri dishes undisturbed until the red plaster has completely hardened. Once fully cured, they are ready to be used in the classroom activity.

Notes

• Prepare the plaster bases several days in advance to ensure they are completely dry before learners begin carving.
• Keep the red layer thin to make carving easier and to clearly reveal the white plaster underneath.
• Keep the white base layer thicker so it provides strength and support. This reduces the likelihood of the plaster breaking when learners apply pressure while carving.
• Whisk the plaster mixtures slowly to minimise the introduction of air bubbles.
• Pour the plaster slowly into the Petri dishes to further reduce trapped air bubbles and create a smoother surface.
• Gently tap the Petri dishes after pouring each layer to help release any remaining air bubbles.

Curriculum Connections

For Educators and Home Educators: this activity supports learning in the following Australian Curriculum V9.0 - Science areas:

Earth and Space Sciences - rock types, the rock cycle and deep time
Science Inquiry Skills - observing, classifying and modelling
Science as a Human Endeavour - science, culture and knowledge systems

Need Assistance?

If you have any questions about this activity or the tutorial, please get in touch with the DeadlyScience team here.

We're happy to help!