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NESA Accredited Teacher
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High school chemistry & physics specialist 30+ years
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The Crazy Scientist in primary schools — 15 years
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International conference presenter on science education
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Creator of the LAB™ Learning System
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Curriculum aligned: NSW Science & Technology K–6 (2024)
A picture is worth a thousand words — check this out and see if you can spot the science hiding in plain sight.
From the LAB
What you will need
• Table salt (or equal mix of baking soda and salt to simulate natron)
• Two identical apple slices or small pieces of raw chicken
• Two small containers or ziplock bags
• Paper towels
• Labels
• Camera or phone for daily photo documentation
How to do it
1
Set up normal conditions
This is called a control
Place one apple slice (or chicken piece) in an open container labelled 'Control'.
Leave it exposed to air at room temperature.
3
Burry the 'mummy'
Place your second apple slice in a container. Pour natron mix over it until it's completely covered.
Seal the container. Label it 'Salt'.
5
Daily Records
Each day, photograph both samples and record what you observe: colour, texture, any visible mould, smell (note but don't breathe deeply).
Do not open the salt container — just observe the control.
2
Make the Natron mix
Mix equal parts table salt and baking soda to simulate
Egyptian natron. You need enough to completely bury your sample — at least 1–2 cm on all sides.
4
Observe Day 1
Take a photo of both samples now — this is your baseline.
6
Day 7 Reveal
Open both containers after 7 days. Compare texture, moisture, colour, and any signs of decomposition.
Did it work? Share the science! Tag @the_crazy_scientist on Instagram — we love seeing your experiments!
The Mummy Maker
Designed by Darin Carr (BSc, DipEd)
NESA Accredited Teacher Chemistry & Physics Specialist
Creator of the LAB™ Learning System
Egyptian embalmers preserved bodies for 3,000 years using a mineral they pulled from dried lake beds. That same mineral is in your kitchen right now.
9-12 yrs
Easy
15
min
Stage 2, Stage 3
>
The Mummy Maker
The Crazy Scientist LAB Learning System™
Every experiment follows The Crazy Scientist Lab Learning System™ — a simple way to help kids think like real scientists.
We
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LINK to what they already know,
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ACTIVATE curiosity through hands-on discovery
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BUILD understanding that actually sticks.
You’ve put meat or fruit in the fridge and forgotten about it. What happened?
Within days, decay started — colours changed, texture broke down, it started to smell.
Now think about the ancient Egyptians — no refrigerators, 40°C desert heat. They wanted to preserve bodies for eternity.
They figured out a solution that worked. What do a fridge and a bag of salt have in common?
Open both containers on Day 5 and compare.
Describe every difference you can see — colour, texture, moisture, smell. What surprises you most?
Look carefully at the control sample. What can you see growing or changing on the surface? What do you think is causing it?
The salt-buried sample looks very different. What do you think the salt actually did to it? Make your best prediction before you read the science.
Your control sample is rotting. The salt-buried one is not. What did the salt change about the conditions that tiny living things need to survive?
Did the salt kill the tiny organisms causing decay — or did it just take away something they need? What’s the difference between killing and preventing?
Egyptian mummies were buried in dry desert tombs after the natron process. How did the hot, dry environment help the preservation last thousands of years?
"Want the full teacher guide? The Crazy Scientist Lab includes classroom delivery tips, how to manage the WOW moment, differentiation for Stage 2 & 3, — ready to teach tomorrow."
Think Like a Scientist
Scientists don't just do ONE experiment; they change one part of the experiment (independent variable) and then see how it affects another part of the experiment
(dependent variable)
Change ONE variable and test again.
Salt concentration — light sprinkle vs half-buried vs completely buried. Does completeness of coverage matter?
Food type — apple vs banana vs raw chicken. Which preserves most effectively in salt?
🧪 Try it! Change ONE thing and test again. What did you discover?
Want to go deeper? Tap a section below to explore. ▼
The Science Behind It
What's really happening?
Salt is one of the most powerful preservers ever discovered — and humans worked this out thousands of years ago. When you bury food in salt, something surprising happens: water inside the food moves out towards the salt on the outside.
This happens because water naturally moves from areas with less dissolved stuff in them towards areas with more dissolved stuff — trying to balance things out.
The food loses moisture and starts to dry out. Bacteria — the tiny living things that cause decay — need water to grow, feed, and multiply. Take the water away, and they simply can't do any of those things. The decay stops.
Why removing water stops decay?
Bacteria are living things, and like all living things they need water to survive. Without water, they can't digest food, can't produce energy, and can't multiply. They go dormant — not dead, but completely shut down.
As long as the material stays dry, the bacteria stay inactive. The moment water returns, they can start up again.
That's why salt-preserved food needs to stay dry to stay preserved — and why a mummy that gets wet can begin to decay again, even after thousands of years.
How the Egyptians used this?
The ancient Egyptians used a naturally occurring salt called natron, which they collected from dried lake beds in the desert. They packed bodies completely in natron for around 40 days to draw out all the moisture, then carefully wrapped them in linen bandages.
The whole preservation process took 70 days. It worked so well that Ramesses II, who died over 3,000 years ago, still has his own hair, skin, and facial features intact today.
Real-world connection
The same water-removal method is still used today in beef jerky, dried fruit, sun-dried tomatoes, and salt-cured fish. All of these are preserved without refrigerators or chemicals — using nothing more than moisture removal.
The same technology the Egyptians developed 3,000 years ago is still on every supermarket shelf today. Next time you eat a piece of dried mango, you're using mummification science.
Try next
See what happens when bacteria DO have everything they need — warmth, moisture, and food → [The Invisible Colony]
Explore another chemical change that permanently alters a material → [Hidden Messages]
Extension: G&T Years 5 & 6
What is osmosis?
Osmosis is the movement of water through a thin barrier from an area of low dissolved substances to an area of high dissolved substances.
The cell walls of food act like thin membranes — they let water pass through but not large dissolved particles like salt. When you surround food with salt, the high concentration of salt outside draws water through those cell walls and out of the food.
The food loses water even though nothing is squeezing it — the movement is driven entirely by the difference in concentration on each side of the barrier.
Imagine a thin bag of watery liquid placed in a bowl of concentrated salt solution. Predict what would happen to the bag over time. Would it swell or shrink? What would be happening at the level of the water molecules moving through the bag's surface?
Why water is essential for living cells
Every chemical reaction inside a living cell takes place in water.
Enzymes — proteins that control chemical reactions — only work in a watery environment. Bacteria can't absorb nutrients, produce energy, or reproduce without water. When water is removed, all of these processes stop.
The bacteria enter a state called dormancy: metabolism completely shuts down, but the cells remain intact and are capable of restarting if water returns.
This is the crucial distinction: salt preservation doesn't kill bacteria — it just removes what they need to function.
Why salt concentration matters
The more concentrated the salt, the faster and more complete the water extraction. This is why samples only lightly sprinkled with salt preserve less effectively than samples completely buried.
Egyptian embalmers had to figure out the right amount through centuries of trial and error — long before they had the science to explain why it worked.
Vocabulary
Osmosis
The movement of water through a thin barrier from an area with less dissolved substance to an area with more, trying to balance the two sides out.
Bacteria
Microscopic living things are found almost everywhere. Many types of bacteria cause food to decay by breaking it down. They need water, warmth, and nutrients to survive.
Decay
The process of a material breaking down due to bacteria and other microorganisms. Signs of decay include colour changes, soft texture, mould, and smell.
Dehydration
The removal of water from a material. Salt preserves food by causing dehydration — drawing the moisture out until bacteria can no longer function.
Preservation
Stopping or slowing decay so that a material stays intact for longer. Salt, cold temperatures, and drying are all methods of preservation.
Natron
A naturally occurring salt found near dried lake beds in ancient Egypt. Embalmers used it to draw moisture out of bodies during the mummification process.
Know a parent or teacher who'd love this? Send it on! 👇
The Crazy Scientist books
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Designed by a practising NSW classroom teacher (30+ years experience), these books directly support NSW Science & Technology (2024) outcomes and reinforce “Working Scientifically” skills.
Perfect for classroom libraries or home explorations.
For teachers (YouTube)
— Science Before the Bell
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