Have you ever heard of hot ice? It seemed impossible because ice was usually cold. However, we are not talking about ordinary ice. You can make sodium acetate using the same ingredients that make baking soda volcanoes. When sodium acetate is cooled below freezing, a liquid is formed, ready to freeze at the slightest trigger. In the process of forming solid crystals, a hot blast is released and you get "hot ice".
Step
Method 1 of 2: Making Sodium Acetate at Home
Step 1. Take a large pot
Choose a clean pan made of steel or Pyrex with a minimum capacity of two liters. "Hot ice" is non-toxic. So, don't be afraid the pan is damaged and can't be used anymore.
Do not use copper pans
Step 2. Add baking soda
Pour 3 tablespoons (45 ml) of baking soda into the saucepan.
Do not use baking powder as it contains other substances that can affect the process
Step 3. Pour in the white vinegar
Measure out about a quart of white vinegar, then slowly pour it into the saucepan. The liquid will immediately fizz and foam. So, don't pour the vinegar all at once so it doesn't overflow.
In this case, you're using 5% acetic acid, which is standard vinegar. You don't need to take accurate measurements.
Step 4. Wait for the liquid to stop fizzing
Vinegar (acetic acid) and baking soda (sodium bicarbonate) react to produce sodium acetate, along with carbon dioxide, which causes all this hiss. While the liquid continues to sizzle, stir well to dissolve all the baking soda. Then, wait for the reaction to stop.
Step 5. Make sure the liquid is completely clear
If you still see grains of baking soda, add vinegar until it's all dissolved. The remaining baking soda can freeze the "hot ice" prematurely in the next process.
Step 6. Heat the liquid until the first layer appears on the surface
The largest composition of vinegar is water, which must be evaporated. After about 90% of the liquid has evaporated (usually it will take half an hour or so), a solid layer begins to form on the surface. This means all the excess water has evaporated and you need to turn off the fire as soon as possible. If there is too much solid layer, the liquid will become cloudy and will not function properly.
- If the liquid is too cloudy and browned, add a little vinegar and bring to a boil again.
- Initially, sodium acetate was formed as a compound "sodium acetate trihydrate", which means it contains water. After all the water is gone, the water molecules start to evaporate and the sodium acetate becomes “sodium acetate anhydrous”, which means “without water”.
Step 7. Scrape the crystals on the walls of the pan
Once the water has evaporated, you will see the sodium acetate crystals stick to the walls of the pot. You will need it later. So, take a spoon to collect them in a separate container. You can do this at any time while the liquid continues to boil.
Step 8. Pour the liquid into a sealable container
Use a soup spoon to pour the liquid into a clean Pyrex saucepan or other heat-resistant container. Make sure that no solid crystals are carried into the container. Close the container tightly.
It is recommended to add 1 or 2 tablespoons (15-30 ml) of vinegar. The vinegar will help keep the solution in a liquid state and prevent the formation of a solid layer again
Step 9. Cool the container in an ice water bath
Wait for the sodium acetate container to cool to room temperature or lower. This process can take 15 minutes if you're using ice-cold water, or longer if you're placing the container in the refrigerator. The goal is to make sodium acetate trihydrate "super cool". This means the liquid will fall below freezing, but remain liquid.
If the liquid freezes at this stage, there may be solid crystalline particles in it or other contaminants. Add a little vinegar, reheat the solution on the stove, and repeat the procedure. This process is difficult. So, it rarely works the first time you try
Step 10. Add a small amount of sodium acetate crystals to the solution
Use the powder you collected from the pan when evaporating the solution. Start by adding a pinch or two of crystalline powder. If nothing happens, add more.
Step 11. Observe the formation of hot ice
Solid sodium acetate serves as seed crystal for producing all supercooled acetate. Since the sodium acetate is supercooled and ready to freeze, the addition of solid particles will cause a rapid chain reaction and freeze the entire solution. This process releases heat, which can be felt easily if you hold your hand near the container.
If this does not happen, there is a problem with the solution. Add more vinegar and bring to a boil again, or try a more reliable method using commercially produced sodium acetate as described below
Method 2 of 2: Using Commercial Sodium Acetate
Step 1. Find sodium acetate trihydrate
Although it is an inexpensive and non-toxic material, it is not easy to find it in local stores. It might be easier to buy it over the internet. You may be able to get it by opening a heat pad which gets hot when you squeeze it.
Sodium acetate is also sold in the form of “sodium acetate anhydrous”, and some suppliers do not specify the form of their product. The instructions below cover both forms of sodium acetate
Step 2. Place the sodium acetate in the boiling water
Pour the sodium acetate into a steel or Pyrex container, then place the container in boiling water. The sodium acetate will melt into pure liquid sodium acetate trihydrate or “hot ice”.
- If the sodium acetate doesn't melt, it means you bought anhydrous sodium acetate. To convert it to sodium acetate trihydrate, add hot water without removing it from the pot of boiling water. You need about 2 ml of water for every 3 g of sodium acetate so that the substance is completely dissolved.
- Do not use all of the sodium acetate. Later, you will need some of it.
Step 3. Refrigerate immediately
Pour the liquid into a clean container, cover it, and place it in an ice bath or refrigerator until it reaches room temperature or lower. Make sure there are no solid sodium acetate particles in the container. Otherwise, the liquid will freeze too early.
Step 4. Add a small amount of solid sodium acetate to the cold solution
The solid crystal will serve as a nucleation point that allows other sodium acetate molecules to persist and develop into a crystalline form. In no time the whole container will look like a block of ice, but radiate heat!
Other contaminants can also trigger clotting if they are properly shaped. This means you can start freezing by touching the solution with a toothpick or finger. However, solid sodium acetate is the only reliable way to carry out this process
Tips
- You can make an ice sculpture if you pour the solution into a pinch of solid crystals. The solution will solidify upon contact with the crystals and will continue to solidify as you pour the solution. In no time, you will have an ice tower!
- Homemade hot ice is more difficult to use and produces less spectacular results than store-bought ones. If you're having trouble, add more vinegar, bring the water to a boil, and try again.
- You can melt the hard "hot ice" and repeat the cooling process again. Since you no longer need to evaporate the water, you can defrost hot ice in the microwave.
