That it was the “Best Class EVER” seems to be the common refrain every year by most every student for 30 years after the Dry Ice Day and this year was no exception! Dry Ice is an exciting chemical to bring to the chemistry classroom because it affords endless possibilities for fun. I have a few fun activities that I do each year with my grade 11 chemistry class. In years past I have also done these activities with Scout Groups, my children’s birthday parties, Specialized Development Education Classes, and all high school science classes. With minimal safety suggestions dry ice presents a unique set of activities that can be fun for all age groups.
Safety for all activities
- It is assumed that the activities described below are performed by a trained chemist whose primary concern is safety first.
- All normal dry ice protocols should be put into practice when working with dry ice (i.e. proper ventilation; that dry ice is not to be touched except with appropriate tongs; that dry ice should not be placed in a vessel that might explode like a capped Erlenmeyer flask).
- As an added safety measure, I ask that students keep their safety googles on at all times because occasionally a film canister lid can go flying. I always practice “safety never takes a vacation!”
matter, physical & chemical changes, changes of state, pressure, gas laws
My class periods are 72 minutes long and we can easily fit in all three activities plus a couple of other activities / demos.
Two of the three activities I show in this article involve making bubbles. Over the years my bubble recipe has indeed evolved much for the better! Currently my favourite recipe is mixing the following:
- 1 cup Dawn Dish Soap (In my experience DAWN Dish Soap perhaps works the best but do feel free to substitute with your favourite brand.)
- 6 cups of water
- 2 Tbsp glycerin
- 1 package of unflavoured gelatin
This soap mixture stores well if you do not use it all in one setting. You would likely need two batches for a full day of classes. I always have a bottle available (see picture).
Figure 1: Water jug bubble maker with vacuum hose
Activity 1 - “Wish bubbles” Materials
- 5 gallon (18 L) Water Jug (see figure 1 for the set up)
- 1 piece of vacuum hose (make sure to tape off any sharp edges)
- 1 large bowl to hold the bubbles – be sure it is wide enough to allow the vacuum hose to reach the bubble mixture unimpeded
- Flat surface (e.g. Desk or lab bench)
- Bubble Mixture (see above)
- Dry Ice - The dry ice I use is in the pellet form and it is free from Linde (formerly Praxair). If I must store it overnight, I use an unsealed cooler.
Figure 2: Homemade Cooler Device
Activity 2 - “Boo Bubbles” Materials
Same as Activity 1 except for no water jug; instead a “homemade” cooler device. See figure 2.
Activity 3: “Film Canister Races – A Healthy Competition" Materials
- Film canisters with lids
- Dry Ice
Activity 1: “Wish Bubbles”
- Pour the bubble mixture (see the above recipe) into the plastic bowl. Use your judgement of course but I usually make sure the bowl is at least ½ full;
- Place a small amount of the bubbles on a flat surface. You need it flat so that bubbles can form without popping due to friction from the surface;
- Place warm water (approximately ¼ full) into the water jug;
- Place enough dry ice into the warm water such that there is gas emanating from the jug;
- Place one end of the hose (the unrefined end) onto the opening of the water jug. Place the smoother end of the hose into the bubbles. Attempt to move a bubble from the bowl onto the flat surface. This is more difficult when the gas is moving fast out of the water jug. Eventually, the gas produced is slower and it becomes easier for the students to make a bubble;
- Students in my classes have attempted to make the largest bubble; to make bubbles within bubbles; to join multiple bubbles to name a few.
- A completely unscientific component I’ve added is to “Make a Wish” before the dry ice bubble “pops.” This I know is seemingly silly but makes them feel less sad when their bubble inevitably pops.
- Note you will have to continually change the water and add dry ice, as needed.
Activity 2: “Boo Bubbles”
- Fill a bowl approximately ½ full with the bubble mixture (see the recipe above);
- Place a small amount of the bubbles on the flat surface or one’s hand;
- Place warm water (approximately ½ full) into the “homemade” cooler device;
- Place enough dry ice into the warm water such that there is gas flowing out of the funnel;
- Place the funnel into the bubble mixture in the bowl. Attempt to “drop” a bubble from the funnel. My students have done a variety of things from this point – played catch the bubble (hands must have soap on them to work), or place/build bubbles onto the flat surface.
- Note you will have to continually change the water and add dry ice as needed.
Activity 3: “Film Canister Races” – A Healthy Competition.
Special Safety Measures - Students should never place themselves physically over the film canister just in case the lid were to explode and hit them.
- Fill the film canister 1/3 full of water;
- Have students practice placing the lid on top. Have students set up their lids and tongs such that they can put the lid on as quickly as possible;
- Place an uniformly sized piece of dry ice beside each film canister;
- I have students start with their hands behind their backs;
- The teacher calls out “Ready—Set—Go!”;
- Students will use their tongs to place the dry ice in the film canister. Then they place the lid on top and stand back;
- First to blow the lid wins!
The“Chemistry” Taught Before The Dry Ice Bubbles Day - See notes below for both Grade 9 and Grade 11 chemistry courses.
Grade 9 Chemistry Unit (Junior Science) - Topics Taught Prior to the ‘Dry Ice Bubbles Day’
Physical and Chemical Change
Changes of State
Examples of What to Discuss During or Prior to the “Dry Ice Bubbles Day’
Safety concerns involved with dry ice.
Carbon dioxide is made of one carbon and two oxygen atoms. Show the Bohr-Rutherford diagrams for carbon and two oxygen atoms. A brief discussion on how they might bond to become “like” the Noble Gases.
The state of carbon dioxide is a gas at room temperature. At high pressure and low temperature carbon dioxide changes from a gas to a solid [this change of state is deposition]. The temperature of dry ice is approximately -780C. At room temperature, dry ice (solid) changes to a gas, this is called sublimation. These are unique changes of state because deposition and sublimation do not pass through the liquid state.
Grade 11 Chemistry (Senior Chemistry) - Topics Taught Prior to the ‘Dry Ice Bubbles Day’
Pressure (pressure conversions) and temperature (Kelvin conversions).
Gas Laws (Boyle’s,Charles, Gay Lussac’s, Combined)
Examples of What to Discuss During or Prior to the “Dry Ice Bubbles Day’
- Students work through my adapted version of the Flinn Scientific Wet-Dry Lab on the same day as the Dry Ice Bubble Day. As such there is pre-lab work needed to be done prior to the actual experiment.
The following is done for pre-lab preparation:
a) Answer questions on the characteristics of dry ice e.g. temperature and pressure [for practice, conversions of both temperature and pressure are done];
b) Answer questions on phase diagrams and triple points [this has NOT been taught in class but instead they learn about it in the pre-lab phase];
c) Research uses of dry ice during the COVID pandemic;
d) An understanding of the special safety considerations involved in working with dry ice;
e) Answer a set of multiple choice questions of safety considerations involved in working with dry ice. This is a computer quiz in which they must receive an individual score of 100% before being allowed to work with the dry ice.
Prepare the devices and the bubble mixture.
Obtain dry ice.
- Thank you to Linde Canada for supplying me with dry ice each semester.
- Thank you to my classes for “filling my bucket” with the “joy” you always seem to have when Dry Ice is in the classroom! Life is good!
- Thank you to my husband, Matthew Clifford, my editor-in-chief.
For Laboratory Work: Please refer to the ACS Guidelines for Chemical Laboratory Safety in Secondary Schools (2016).
For Demonstrations: Please refer to the ACS Division of Chemical Education Safety Guidelines for Chemical Demonstrations.
Other Safety resources
RAMP: Recognize hazards; Assess the risks of hazards; Minimize the risks of hazards; Prepare for emergencies