Before you attempt to make ice spheres read the video description.
The mixture of dry ice and alcohol that I use in this video forms a liquid at a temperature well below -100 degrees Fahrenheit, easily capable of freezing anything containing moisture. There is a possibility of frostbite if the liquid is in contact with skin for any more than a second or two, so great care must be taken. Tongs can be used to safely lower the balloons into the mixture. To cool the alcohol, dry ice should be added to the bottom of the water cooler first, then the alcohol slowly poured in over it. Dry ice should never be dropped into a pool of alcohol unless the alcohol is already very cold or else the dry ice will evaporate quickly and the rapid boiling will cause the container to overflow. Isopropyl alcohol is a flammable liquid therfore care should be taken to avoid flame, don’t fogret adequate ventilation. Isopropyl alcohol is also not an edible type of alcohol, so care should be taken not to get any into the drink.