On average, humans exhale approximately 500 kilogrammes of carbon dioxide each year. Plants, too, utilise carbon dioxide in photosynthesis, which leads them to release oxygen that people breathe. The gas is also the basis of dry ice, which is nothing more than frozen carbon dioxide; as such, it is a naturally occurring substance in Earth's atmosphere and is perfectly safe for use. Dry ice is simple to freeze and, with a pair of insulated gloves, also easy to handle. eBay has a range of dry ice products available, from fog machines to dry ice packs, dry ice fluid to intercoolers, and more. And, as always, to check the bargain prices eBay Deals has on camping equipment.
When frozen, carbon dioxide converts from a solid to a gas with no liquid stage in between, ultimately arriving at a target temperature of -78.5 Celsius. A popular use of dry ice is keeping frozen foods frozen, especially when shipping. In case of power outage, dry ice can go in the freezer to protect food. Travellers, campers, and backpackers often put dry ice in their food containers to ensure they have sufficient materials for mealtime and snacks. The rule of thumb is to purchase 4 to 9 kilogrammes of dry ice, depending on cooler size, per 24 hour of use. Always place the dry ice on top of the food for optimal cooling.
Other uses for dry ice include science projects, school experiments, special events, and rock concerts. Dry ice forms from pure carbon dioxide gas that compresses to the point of liquefaction. Sizes of dry ice machines range from handheld models to commercial ones; as expected, the latter fog machines create larger, longer-lasting dry ice than the former. Through the use of hydraulic pressure, commercial machines can create a 25-kilogramme block of dry ice in less than one minute.
Science classes across all levels of education often utilise dry ice to teach a range of topics; amongst the many things dry ice can create are a cloud chamber, a comet, sodium bicarbonate (baking soda), and a volcano. Both Alpha and Beta particles appear within a cloud chamber. The chamber itself is a bit complex to create; however, these steps instill an understanding of the importance of process in young people. Cloud chamber creation requires a freezer-proof, shallow, clear glass container (such as those from Pyrex or Corning). After creating the cloud, students can use a light to identify and marvel at the vapour trails they have created.
Also known as sodium hydrogen carbonate or baking soda, a sodium bicarbonate experiment requires only four ingredients: dry ice, ammonium carbonate, sodium, and vinegar. Television and movies have featured countless scientific volcano experiments over the years, and now thanks to the broad availability of dry ice, elementary and high school science teachers can replicate the process in the classroom. Creating a comet is perhaps the most complex experience conducted in school science classes, requiring multiple supplies in addition to dry ice, teachers need to obtain a large bowl, a garbage bag and smaller bags, gloves, a hammer, sand, water, and a few drops of ammonia. Detailed instructions are widely available on the internet.
A multitude of additional fun activities awaits the adventurous teacher and her pupils. Lessons abound on the internet, including a list of over 100 experiments provided by the San Francisco Exploratorium, Brian Rich's series The Saturday Scientist, and teacher lesson plans and projects from Anthony Cody's "Science Education Zone".
First and foremost, no one should handle dry ice without appropriate protective gloves; such cold temperatures can cause burns in a short period of time. Store dry ice in an insulated container, such as a good ice chest; an airtight container is a no-no, however, as it may expand, or even explode. Proper ventilation is necessary, too, so that carbon monoxide poisoning does not occur. Accumulation in low spaces is a very real concern, as dry ice is heavier than air. To prevent carbon dioxide poisoning, use a ventilated space, such as a car with the windows open, when transporting dry ice for more than 10 minutes.
Dry ice is both fun and functional. Whether for indoor or outdoor use, the transformation of carbon dioxide gas into frozen air is entertaining and practical. Whatever your need, you can find a wealth of dry ice supplies and accessories on eBay. Need a cooler or ice chest? A pair of protective gloves or what about a dry ice machine? Peruse the options on eBay, or conduct a specific search to find just the product you need. You can use dry ice at home, in educational experiments with your kids, or at school for science learning; you can put it in a cooler to either take camping or ship cold foods across the country; or you can keep the contents of a refrigerator or freezer cool in case of power outage.