Inside: The purpose of this fun Ice Archeology experiment is to see what kinds of things preserve well in ice and what happens to them when they are defrosted.
My kids love archeology. They read books about it and spend a lot of time digging in the backyard, hoping to find dinosaur bones. (They are also known to jump from sheer joy at discovering a piece of porcelain toilet in place of a dinosaur bone. You can find all kinds of things when you dig in the Chicago backyard).
And did I mention the summer they decided to dig a swimming pool in our backyard?
You would be surprised how much compacted rocky dirt four kids can dig up, given the motivation! All that digging made our backyard look crazy messy, but it did keep my kids outside and exercising for most of that summer. So we were okay with that.
But back to archeology!
The Science of Ice Archeology
If you read archeology books with your kids, you already know that ice seems to act as a preserver. If something freezes in ice, it can remain virtually unchanged for thousands of years. The trouble begins when the ice melts and the objects are exposed to oxygen, sun, and wind. If scientists do not move the items to a safe location quickly enough, the deterioration is fast and merciless.
Ice Archeology is truly fascinating!
When my kids and I read an article about two baby mammoths discovered in Siberia in 2017 that dated back 40,000 years, we were hooked and started digging for more (excuse the pun).
Here are some other things that were recently discovered in ice:
- 1700-year-old woolen tunic with signs of mending by its Iron Age owner,
- bodies of three Incan children that helped scientists learn more about human sacrifice in Argentina (for example, children were very well fed the year leading up to their sacrifice), and…
- a 5,300-year-old body of a man who carried Lyme disease (it’s fascinating if you realize that officially Lyme disease was discovered barely 40 years ago!!!)
So, the more we read about items frozen in time, the more questions we had. But the most pressing were these:
- What kinds of things preserve well in ice?
- What happens after they are defrosted?
Join us for this archeological experiment! It spans a couple of days, which might seem challenging, but it’s worth it.
With this fun hands-on activity, your kids will learn:
- Principles of observation and investigation,
- Planning and questioning,
- Critical thinking,
- Problem–solving, and
- Sharing ideas (if you give them a chance to talk 🙂
Ice Archeology Experiment
What you need:
- Ice cube tray
- Materials of various textures, sizes, and densities: writing paper, red pepper flakes or peppercorns, buttons, candy, fabric, metal, candy sparkles, orange peel, colorful tissue paper, food crumbs, toilet paper, plastic, etc.
- Pebbles to keep light items down
- Magnifying glass
- Notebook and pencil
- Our recording sheet (to write down the items to be frozen, and then keep track of what happens to them over time)
What to do
1. Gather your items
Place testing samples in ice cube trays. We walked around the house and gathered a wide variety of samples, from a button to cookie crumbs.
Top (from left to right): feather, tissue paper (weighted down with a stone), plastic bug, pirate coin on a chain, peppermint, rose petal, shiny button.
Bottom (from left to right): glitter, writing paper (weighted down with a stone), LEGO figurine, clay hearts and marbles, buttons, bread, orange peel.
2. Add water
Pour water in each section of the ice cube tray, and remember, if necessary, use pebbles to keep light items like tissue paper, dry leaves, and bread crumbs from floating to the surface.
Place it in the freezer for a few days.
Remind kids why the freezer is a quick and easy method to preserve food. (In the freezer, bacteria can’t grow and multiply).
Ask, what kinds of food do we usually put in the freezer?
After they list a couple of things ask about items in your pantry.
Why do we not bother freezing oil, dry pasta, and canned soup?
Freezers do such an important job. It’s fascinating to consider how much we’ve gained from this invention, but all too often we take our refrigerators for granted. (Unless they break as our refrigerator did recently).
I’ve just read an article about the history of refrigerators and learned that, for example, in countries like India, 70% of people don’t own refrigerators. That’s today!
Pop the ice cubes out of the tray and place them on a high-rimmed dish or water-resistant tray.
What can you say about the condition of the objects?
Can we answer our first question, What preserves well in ice?
In our case, everything was preserved well from bread crumps to buttons.
We love watching ice slowly melt, especially when we touch it with our hands.
Sometimes nature can act as a natural freezer and help us discover things from times long gone.
What does it feel like to be the one to find those priceless artifacts? Is it glamorous? Is it more of being at the right place at the right time?
You can go online and find “a day in the life of an archeologist” sites to gain a better understanding of what day-to-day life might look like for them.
5. Expose to elements
Place your items outside where they can be exposed to sun, flying debris, and wind.
If this isn’t possible, continue this experiment inside but it wouldn’t be as dramatic. Allow the ice to melt completely, and then let the items dry naturally. If you are impatient, you can remove the objects from the water with tweezers to help them dry faster.
What do you notice about the condition of your objects now?
My kids said, “Yuk!”
The rose petal is definitely unrecognizable, and the soggy bread looks pretty unappetizing.
Keep the objects for a few days in a bright place (outside in the sunlight is best). If the items are light, keep them down with a rock.
As you can see, our items are getting dirtier by the minute. I didn’t realize we had so much dust flying around our backyard.
Did you notice that the water is frozen? The temperature at night suddenly went below freezing.
Study the condition of your items every day for the next few days.
Do they look different from when they were first frozen? If yes, how? What’s happening to the temperature during your experiment? We suddenly got wet snow!
The freeze-melt-freeze cycle was not good for our items.
While doing this experiment, you can ask kids:
Why does ice preserve things?
How does ice preserve archeological finds?
Does ice preserve everything equally well?
8. Draw conclusions
After it became obvious that the temperatures will stay below freezing for a while, we took the items inside for final evaluation and conclusion.
Pretty sad! Exclaimed my kids looking at our plate. Some items are simply unrecognizable and it’s just after one month of being outside! Imagine what happens after thousands of years!
Our pirate chain suffered a lot of damage. I see Rust Removing Experiment in our future 🙂
I hope you will enjoy this activity as much as we did. We love the fact that it allowed us to gain a better understanding of what archeologists go through when they rush to get artifacts out of the elements and into a controlled lab condition.
If you want to squeeze the most learning out of this experiment, help your kids record their observations in our science sheet. Guide them to list the items to be frozen, then write down what happens to them after one week of being outside, after two weeks, etc.