Dry ice is frozen carbon dioxide, which is the gas you give off with your breath. It is called dry ice because, under normal atmospheric conditions, it passes, or sublimates, from the solid to the gaseous state without passing through the liquid state. If you're playing a science experiment or recreating a fun fog effect, follow this guide to safely handle dry ice.
Steps
Part 1 of 3: Buying and Transporting Dry Ice
Step 1. Purchase dry ice at your local grocery store or supermarket
In America, for example, you can buy it at Safeway, Wal-Mart and Costco stores.
- Try to get it just before using it. Since it constantly passes from the solid to the gaseous state, it has a very short "life" autonomy: every 24 hours, the amount of ice that passes from the solid to the gaseous state varies from about 2.5 to 4.5 kg.
- While most people can safely buy dry ice, some stores will require you to be at least 18 years old in order to sell it to you.
Step 2. Purchase dry ice in briquettes
This is in fact the necessary form both to reproduce a scientific experiment and to recreate a fog effect.
- Dry ice is also sold in pellets, but this version is mainly used for the cryogenic cleaning of some surfaces or for transport to the healthcare sector.
- The price of 0.5 kg of dry ice can range from € 1 to € 3 approximately. While the cost can change based on quantity and location, it tends to be quite low.
Step 3. Place the dry ice in an insulated container, such as a portable icebox or plastic cooler
Since dry ice is much colder than regular refrigerated containers (-78.5 ° C), it is not possible to keep it cold in ordinary refrigerators or freezers.
- The thicker the container insulation you use, the slower the dry ice will sublimate.
- Open and close the container as little as possible to slow down the sublimation process. You can also fill the rest of the container with crumpled paper to limit the gaps and thus further slow down the sublimation.
- Placing dry ice in the freezer may cause the thermostat to turn off. Since dry ice is extremely cold, the freezer will turn off to prevent the food from freezing too much. Likewise, if the freezer breaks down and you need to keep frozen food in it, you can put dry ice in it and it will act as a good substitute.
Step 4. Put the cooler in the car and roll down the windows
Remember that dry ice is nothing more than carbon dioxide and it is therefore dangerous to inhale it in large quantities.
Fresh air is especially important if you have to carry dry ice for more than 15 minutes. Being in a poorly ventilated area and in the presence of dry ice can cause rapid breathing, headaches and can even be fatal if you stay there for prolonged periods
Part 2 of 3: Handling Dry Ice
Step 1. Wear leather gloves and long sleeves when pouring dry ice or opening the container it is in
Although brief contact is harmless, prolonged contact with skin can freeze skin cells and burn you just like fire would.
- An oven mitt or towel can work, too, but they won't provide the same protection that real gloves would. Handle dry ice as you would a hot pan: be careful to avoid skin contact.
- Dry ice burns should be treated like normal sunburn. If the skin is only red, it will heal in a short time. If, on the other hand, the skin has blisters or lifts, treat the area with antibiotic ointment and wrap it with bandages. In case of severe burns, consult a doctor immediately.
Step 2. Keep leftover dry ice in a well-ventilated area
Large amounts of dry ice stored in poorly ventilated areas create an oxygen-deficient atmosphere.
- A lockable tool shed in the yard will have good air circulation and the danger of suffocation for people or animals will be excluded. If you are having trouble finding a suitable place to store dry ice, ask your teacher if there is a safe place to store it in your school chemistry lab.
- Be sure to keep dry ice out of the reach of small children and pets.
Step 3. If you accidentally spilled dry ice, open doors and windows
Dry ice will continue to sublimate, but will be able to dissipate into the air more easily.
Dry ice is heavier than oxygen and will accumulate in the lower part of the environment it leaked into. So, avoid putting your face close to holes or other low and cramped areas, as there will be a higher concentration of carbon dioxide
Step 4. To get rid of dry ice, just leave it in a well-ventilated area at room temperature
If you find that you have too much of it, remember that it is continually undergoing sublimation and just let it evaporate on its own.
- The backyard porch is a great place to get rid of the dry ice. Make sure it is out of reach of other people for at least 24 hours.
- You can also use a fume hood to get rid of dry ice. It is a ventilated appliance where dangerous chemicals can be used or stored. Your school chemistry lab may have one where you can leave any leftover dry ice. Ask a teacher for permission before using it.
Part 3 of 3: Things to Avoid
Step 1. Do not store dry ice in an airtight container
Sublimation from dry ice to carbon dioxide will cause the container to expand, which could explode.
- Dry ice can cause a violent burst if packaged tightly. Some people have received a criminal complaint for closing dry ice in containers until it explodes, thus making it a real "bomb".
- Do not store dry ice in metal or glass containers, as an explosion could create splinters and cause serious damage and injury.
Step 2. Avoid storing dry ice in your basement, basement, car, or other poorly ventilated area
Carbon dioxide from dry ice would gradually replace oxygen and, if breathed in, could cause suffocation.
Ventilate the rooms in which you have stored dry ice before entering them
Step 3. Try not to leave dry ice unattended
Even if there is no one around, leaks or other accidents may still occur if dry ice is not strictly controlled.
Do not leave dry ice on a tiled counter or any solid surface, as extreme cold could crack it
Step 4. Do not throw dry ice down the drain, sink, toilet or trash can
You would risk freezing the water in the pipes and could even cause them to rupture.
