Hot ice is a popular science project and a clear crowd-pleaser at science fairs. Some people also use this in magic tricks. As we all know, hot ice is not crystallized water, instead it is crystallized sodium acetate trihydrate. Moreover, unlike ice made from water, which is cold, hot ice is warm to touch, because of the exothermic reaction taking place during its formation. Thus, hot ice or sodium acetate trihydrate bears semblance to regular ice, however, is a completely different compound. This has resulted in its popularity. However, is it easy to make hot ice? Let's find out.
How to Make Hot Ice from Scratch
In order to make hot ice or sodium acetate trihydrate, we require the compound sodium acetate. Sodium acetate is the product of a reaction between baking soda (sodium bicarbonate) and vinegar (acetic acid). Let's find out how to make sodium acetate from these two compounds.
- One bottle vinegar (One liter)
- Baking soda (One small tin)
- Saucepan and spoon
If you are preparing sodium acetate in a lab setting, then use a beaker to prepare your sodium acetate. If it's a kitchen setting, take a steel saucepan and add one liter of vinegar to it. Then, gradually add baking soda to the vinegar. Effervescence or fizzing is observed, due to the release of carbon dioxide gas.
Do not add too much baking soda at a time. This is to avoid overflow of the mixture. Moreover, do not forget to stir continuously. Keep adding baking soda gradually, till the solution fizzes no more. This means your aqueous solution of sodium acetate is ready.
The next step is to prepare a supersaturated solution of sodium acetate, for which you need to heat this aqueous solution of sodium acetate. Place the solution on low heat and allow the liquid portion to evaporate for about an hour.
Once the amount reduces to half, pour the solution into a smaller vessel and again heat it. You will begin to notice some crust being formed on the sides of the pan. These are sodium acetate crystals. Scrape a few of these pieces and keep aside for future use. Scrape the rest of the crust back into the solution.
You will soon find a film or crust, being formed on the surface of the liquid, in the pan. This is the time to stop heating. Remove the pan from the heat and pour it into a glass jar. Add a bit of water or vinegar, to dissolve the crust formed on the surface. Stir well, ensuring there are no bits of undissolved crust fragments. Then place the lid on the glass jar, so as to prevent further evaporation and crystal formation.
Now, place this glass jar filled with the supersaturated sodium acetate solution, in a dish containing ice-cold water. Allow it to cool for ten minutes. Or else you can place the solution in the refrigerator for an hour.
Once the solution cools, take it out and you are ready to prepare hot ice with it. To prepare a hot ice sculpture, take a medium-sized bowl and invert it (a tray will also do). Place the crust of sodium acetate crystal (kept aside earlier) on the bowl or tray and pour the refrigerated sodium trihydrate solution prepared.
The crust of sodium acetate crystal placed on the bowl will solidify the liquid poured on it, by acting as a seeding site. Using this to your advantage, you can prepare any sculpture of your choice. Moreover, heat is evolved due to the exothermic reaction involved during the crystallization process. Thus, when you touch the freshly formed sculpture it will be hot.
If you are dissatisfied with the shape of the sculpture, just topple the whole sculpture into the saucepan and heat. The solid crystals will turn into the liquid state and after cooling, you can once again make your sculpture. Only make sure you do not contaminate the solution, during the process.
How to Instantly Make Hot Ice
The two raw materials: baking soda and vinegar, used to make hot ice need to be free of impurities. Ensuring this is very difficult, which is why it is better to purchase ready-made sodium acetate. You can purchase it from online stores like eBay, Trade Me, etc. Sodium acetate is also available in warming pads, hand warmers, etc. Just cut open these pads or hand warmers with a knife and empty out the contents. However, sodium acetate obtained from these warming applications will appear like a gel. Nevertheless, it satisfies the purpose. Moreover, purchasing ready-made sodium acetate simplifies and speeds up the entire process.
- Sodium acetate powder (One cup)
- Steel saucepan
In a steel saucepan, add two cups of water and begin heating it. Now, gradually add a cup of sodium acetate into the water and stir, so that it dissolves. Do not add it all at once. Instead, add it gradually, ensuring all the crystals are getting dissolved.
The solution should not be brought to a boil, instead must be heated on low heat. Do not overheat the solution, or else the solution will develop a yellowish or brownish tinge on solidifying. This will not look so appealing in a science fair, as it will not resemble ice.
Keep stirring the solution, as you add sodium acetate crystals. Now, the key here is getting a supersaturated solution. This is because, if the solution is not supersaturated, when the solution is placed in the refrigerator, it will crystallize, thereby defeating the whole aim of the experiment.
Since we are looking for a supersaturated solution, we need to make sure no more sodium acetate crystals dissolve into the water. You will know the solution is supersaturated, when some crystals remain at the bottom of the beaker or saucepan, even after stirring for quite a while. This indicates your supersaturated solution of sodium acetate is ready.
You can also do it the other way round, wherein, you can first add sodium acetate into the beaker and then add water gradually. However, be careful not to add too much water.
Now, that your sodium acetate trihydrate solution is ready, pour it into a glass or any dish of your choice. However, make sure the tiny, undissolved particles present in the supersaturated solution do not get transferred into the glass dish. The presence of undissolved crystals can cause the solution to crystallize. Allow the solution to cool in the refrigerator for an hour or so.
After an hour take the solution from the fridge. You are now ready to make your own hot ice sculpture. Pour the solution over a crystal of sodium acetate and watch how the whole solution crystallizes to form a beautiful sculpture. After making a sculpture once or twice, you will gain better control over your hands and will be able to construct gorgeous hot ice sculptures.
Hot ice sculptures are great science projects for kids and enthrall the people observing the experiment. This experiment is sure to yield good grades. However, make sure you study the science involved in each step, when you present this experiment at a science fair. Be creative and mesmerize those around you with hot ice.