Logo of CSIRO
Connecting Indigenous  Knowledges to the classroom 
Experiment Procedure and Planner 
Traditional cooking methods 
Underground oven 
Student activities 
A photo of several fish embedded on two wooden skewers, being cooked over a wood fire.
Acknowledgement of Country 
CSIRO acknowledges the Traditional Owners of the lands, seas and waters of the area that we live and work on across Australia. We acknowledge all Aboriginal and Torres Strait Islander peoples and their continuing connection to their culture and pay our respects to Elders past and present. CSIRO is committed to reconciliation and recognises that Aboriginal and Torres Strait Islander peoples have made contributions to all aspects of Australian life including culture, economy and science. 
Artwork 
Meeting on Country, Shifting Sands by Aunty Sandra Angus  working with Saltwater People   2026. 
Aunty Sandra Angus is an acknowledged Elder and well respected Aboriginal leader in her community. She proudly identifies as an Australian Saltwater Murri with ancestral roots that extend to the Wiradjuri and Wongaibon people in NSW, the Ngarrindjeri people in SA and the Gunggari and Jaggera people in QLD. 
Meeting on Country, Shifting Sands by Aunty Sandra Angus working with Saltwater People  2026.

Contents 
Contents  ............................................................................................................................. 3
Introduction  ............................................................................................................................. 4
Experiment procedure .................................................................................................................. 5
Experiment planner ...................................................................................................................... 7
Safety precautions ...................................................................................................................... 10
Observations and results ............................................................................................................. 11

Introduction 
For thousands of years, Aboriginal and/or Torres Strait Islander Peoples have used underground earth ovens to cook food slowly using heated rocks, leaves, steam and soil. Vegetables and meat were often wrapped in leaves or paperbark and sprinkled with water before being covered with soil. As the water heated, it changed state from a liquid into gas (steam). The trapped steam and heat helped cook the food slowly while keeping it moist and tender. 
An educational illustration showing a cross-section view of a traditional earth oven method. At the base of a dug pit, a dense layer of glowing, bright red hot rocks radiates heat. Directly above the rocks is a layer of vibrant green leaves. Resting on the leaves is the food, wrapped in brown layers (like husks or leaves) with visible wisps of steam rising from it. The entire pit is covered by a thick layer of soil, forming a rounded mound above ground level to trap the heat. Four black horizontal arrows point to various layers, indicating where labels would go.
In this experiment, you will model an underground oven using a frying pan filled with heated sand. Aluminium foil will represent traditional leaf or paperbark wrapping, while adding or not adding water will be used to experiment how steam affects cooking.  
As you work through this experiment, consider: 

 Why is food wrapped in underground ovens? 


 What happens when water is added to the foil? 


 How does steam help cook the food? 


 What differences can you observe between the potatoes with and without water? 


 How does heat move through the sand and into the food? 


Safety note: This experiment involves heat and/or fire.  
Experiment procedure  
Does adding water affect the texture and moisture of a potato cooked in a model ground oven? 
Equipment 
For each group: 

 Frying pan with lid 


 Sand (enough to fill each pan to  full) 


 2 x medium potatoes (of similar size and shape) 


 Knife 


 Cutting board 


 Aluminium foil (foil) 


 Permanent marker 


 Measuring cylinder or cup (100 mL) 


 50 mL tap water 


 Metal tongs  


 Timer  


 Weighing scales  


 Metal tablespoon 


 Stove. 


Safety 

 Do not touch the frying pan or anything in it once turned on. The heat produced can cause burns.  


 Wear safety glasses. 


 Keep your working area clean. Flammable materials can catch on fire.  


 Steam may escape when the lid is removed. Open the lid away from you. 


 Only the teacher should handle the hot pan and hot sand.  


 Use tongs to handle hot potatoes. 


 Keep a safe distance from the heat source and use tongs when handling materials. 


Method 
1.
 Fill the pan with sand until it is three-quarters full. Heat it on low-medium for 510 minutes. Stir the sand with the metal tablespoon every 30 seconds so the heat spreads evenly. 

2.
 Cut each potato into four equal pieces (quarters). 

3.
 Place each potato piece onto its own sheet of foil (about 30 cm  40 cm). Use a permanent marker to label one foil water and the other no water. 

4.
 Measure 50 mL of water. Hold the foil labelled water in your hand to make a small cup. Add in the potato pieces and pour in the water. Bring the edges 

together and twist to seal it tightly. Seal the no water foil the same way, but without water. 


Diagram of step 4: Adding water to foil
Diagram of sealed foil bag
Figure 1 Diagram of step 4: Adding water to foil (left) and diagram of sealed foil bag (right). 
5.
 Place both foil parcels into the hot sand. Cover them so only the very top is sticking out. 

6.
 Put the lid on the pan. 


Diagram of step 6, a pot on a stovetop.
Figure 2 Diagram of step 6 
7.
 Start the timer and cook the potatoes for 20 minutes on low-medium heat. (Cooking time may change depending on the pan and heat.) 

8.
 Turn off the stove. Use metal tongs to carefully lift the foil parcels out of the sand. 

9.
 Let them cool. Then open the foil and observe and record the texture, softness, and moisture of each potato. Write your results in your Student Experiment Planner. 


Analyse the results 
How will you share your results? Can you display them so that others could understand what you observed? Use your observations to compare how adding water affected the cooking process in the potatoes.  
Reflect 
Write a conclusion based on your results. 
Record your conclusions and responses to questions in the Experiment Planner. 
Experiment planner 
Underground oven 
Student name: 
 

Partners name/s: 
 


1. Experiment question. I am trying to find out... 
2. Hypothesis. 
I think the most effective method will be 
3. All the things that could affect this experiment are: 
Tick the correct answer/s from the options below. 
 Type of vegetable used. 

 Whether water is added. 

 The wetness of the sand. 

 The heat setting on the stove. 

 The size of the pan. 

 Whether the lid stays on when cooking. 

 The amount of sand in the pan. 

 Cooling time before observations are made. 

 How tightly the foil is wrapped or sealed. 

 The cooking time. 


What else can you think of?  
4. The one thing I will change is 
5. I will measure: 
Tick the correct answer/s from the options below. 
 Time it takes to cook 

 The texture of the potatoes after cooking (softness, firmness or fluffiness)  

 The moisture of the potatoes after cooking (dryness or moistness)  

 The temperature of the potatoes  

 The volume of water left in the potato foil.  

 The appearance of the cooked potatoes  

 The smell of the cooked potatoes  

 The mass/weight of the potatoes after cooking 


I will make my measurements using:  
6. I will control (keep the same): 
Tick the correct answer/s from the options below. 
 Type of potato used. 

 Size and number of potato pieces. 

 Amount of sand in the pan. 

 Heat setting of the stove/hot plate. 

 Cooking time. 

 Size and type of frying pan.  

 Amount and size of aluminium foil used. 

 Starting temperature of the potatoes and sand.   


Safety precautions 
Add any additional safety precautions 
What are the risks in doing this 
 How can I manage the risks to stay 
 

Burns:  

 From frying pan  


 Stove  


 Hot sand  


 Heated foil, sand, potatoes 


 Steam escaping when opening foil or removing lid. 


 
 Do not touch heated materials. 


 Only the teacher should handle hot equipment. 


 Use tongs to remove foil parcel form hot sand. 


 Students should stand at a safe distance away to observe. 


 
Cuts:  

 From cutting potatoes. 


 
 Teacher should cut potatoes or students should be taught how to cut safely and be closely supervised. 


 
Slips:  

 Sand spilling and cause slips. 


 
 Keep work area tidy and clean up spilled sand immediately. 


 



 



 



 


Observations and results 
Describe the potatoes before being cooked:  
Draw a labelled diagram of the experiment set up on the stove:  
Record your results: describe the texture and moisture of the potatoes: 
Reflections and conclusions 
1.
 How did the results compare to what you hypothesised? Do the results support your hypothesis? Why/why not? 





2.
 Did the potato with or without water come out as moist, soft and fluffy? What do you think caused this to happen?  





3.
 Was this a fair test? Why/why not? 





4.
 What could be changed to improve the experiment? 





5.
 Do you think the experiment question was fair and clear? Why/why not?  





6.
 What happened to the water? How is steam produced? Draw a diagram to help you explain your answer.  





7.
 How does adding water help the food in an underground oven cook?  





8.
 The pan with sand modelled a traditional underground oven. What role would the leaves or paperbark used to wrap food play in cooking it in an underground oven? Think about why we needed to use foil in this experiment: 





As Australias national science agency, CSIRO is solving the greatest challenges through innovative science and technology. 
CSIRO.  Creating a better future for everyone. 
Contact us 
1300 363 400 
+61 3 9545 2176
csiro.au/contact
csiro.au
For further information 
CSIRO Education and Outreach 
1300 363 400 
education@csiro.au 
csiro.au/education 

