IProposeWe Freeze Carbon Dioxide

Link(s):
How to Freeze Carbon Dioxide aka Make Dry Ice!

Materials:

• CO2 tank (one with a value!) - click for prices!!
  
• gloves
• goggles
• ice bag
• thick jar (no lid)

Procedures:

1. Before you start making dry ice, wear safety goggles and gloves. You can also wear a jacket if you are a bit clumsy. Remember, touching dry ice may cause severe skin damage, so you have to be fully protected when creating such a substance.
2. Cover the nozzle of the tank with the ice bag. Hold the bag tightly. Make sure that it sticks to the nozzle even if the tank produces a significant amount of pressure.
3. Once the bag is held in place, turn the valve of the tank to release CO2. Keep the valve open for about five to 20 seconds, depending on the amount of dry ice that you’re planning to create.
4. Turn off the valve.
5. Remove the bag from the nozzle and transfer the dry ice to a thick jar. Do not close the jar, since the air pressure coming from the solid carbon can shatter the container.
6. Repeat the entire process if you want more dry ice.

Safety Procedures:

• Never let dry ice touch your bare skin—always handle it with gloves.
• Dry ice displaces oxygen in the air, so always use it in a well-ventilated area.
• When transporting dry ice in a vehicle, roll down the window to ensure adequate ventilation, especially if you feel short of breath.
• If you're using dry ice in a confined space, open the door and air out the area before entering.
• Never place dry ice in a tightly sealed container or vessel, because it converts back to gas and creates its own pressure.
• When shipping frozen products with dry ice, notify the carrier prior to shipment.

Scientific Principles:
Freezing Carbon Dioxide makes Dry Ice

More explanations here.