It's time for another amazing experiment with Amy, Mark and Zoom aboard the spaceship curiosity on RTÉjr science show Let's Find Out!
It's made with the help of Science Foundation Ireland and it helps explain the world round us.
Watch the show here on RTÉ Player!
Here, Zoom finds out that snow is made up of water crystals, so two curious kids, Sophie and Patrick, show her how to make another kind of amazing crystal!
Download a full lesson plan here...
You will need:
- Sodium Acetate Trihydrate
- A small pyrex jug
- A toothpick or wooden skewer
- A teaspoon measure
- Clear malt vinegar
- A glass of water
What to do:
- First, make some sodium acetate (Hot Ice) solution:
- Place 100g of sodium Acetate trihydrate in a pan
- Add approx. 25mls of water and begin heating slowly
- Stir until all of the sodium acetate trihydrate has melted
- Once melted, simmer for approx. 5 mins then transfer to a very clean pyrex jug
- Place in the fridge to cool
Now you can make your crystals!
- Put a small amount of solid sodium acetate trihydrate on a saucer
- Carefully remove the sodium acetate solution from the fridge and place on a flat surface.
- Dip a toothpick into the glass of water to wet the tip.
- Then dip the tip of the toothpick into the solid sodium acetate trihydrate so some sticks to it.
- Dip this end of the toothpick into the sodium acetate solution and watch what happens.
CAUTION: the solution may become warm when the crystals form - please do not touch the container.
If you want to repeat this again you can ask an adult to place the jug into a pot of hot water. Heat the pot of water on a medium heat until the solution is clear and all the crystals have dissolved.
Ask an adult to turn off the heat and remove the jug.
You can then let it cool and start again.
If you repeat this many times, you may notice that the solution forms back into crystals as it cools. If this happens, simply add a half teaspoon of clear, malt vinegar to it, mix and return to step 4.
The science bit:
The sodium acetate solution has lots of sodium acetate dissolved in it. It has so much sodium acetate dissolved in it that it cannot hold any more, we call this a saturated solution. When we dip the crystals of sodium acetate into the solution it pushes the solution beyond its maximum and causes all the sodium acetate to come out of solution, in crystal form.
SO WHY IS IT CALLED 'HOT ICE'?
Sodium acetate has a melting point of 51 C and below this temperature it prefers to be a solid. However, when sodium acetate is mixed with water and melted it can remain as a liquid below its melting point. This is called a "supersaturated solution". If this supersaturated solution is then made to crystallise, its temperature rises to its melting point of 51 C immediately and solidifies.
This is where the name HOT ICE comes from and sodium acetate is used to make hand warmers, applying this very same principle.
Also in this episode:
Mark and Amy show Zoom that sliding is possible because there’s very little friction between the snow and a sled. And the whole crew go to a place with lots of snow and sliding - the snowy mountains!
Check out the RTÉ Player to watch the full episode HERE and all the series so far HERE!!
AND there are lots more experiments with videos and full instructions - Just click HERE!