In the summer of 1976, when the USA was celebrating its bicentennial, I volunteered to do some work for the Minnesota Bicentennial Commission. One event was an ice cream social to be held on the lawn of the Minnesota Capitol. I was going to be one of the people who dished out the free ice cream for the public, but my first task was to pick up the ice cream from the warehouse of the company that donated it—I think it was Land o' Lakes. I did this on a Saturday; the event was the next afternoon.

It was a very hot day, in the 90's. When I arrived at the warehouse, the manager asked me, "What have you got to put it in?" I said, "The trunk of my car." He said, "You can't put it in there. It'll melt!" Then he reconsidered. "Hey, I know what I'll do. I'll give you some dry ice. We'll just turn your trunk into a cooler." So we loaded up my trunk with maybe 200 pounds of ice cream and several pounds of dry ice.

It worked beautifully. I drove the 20 miles or so back to the capitol, and went directly to the state garage where the trailer was stored which we were going to use the following day as the booth from which we would dispense the ice cream. This trailer was also on loan from the ice cream company. It had been delivered earlier, and its refrigerator had been plugged in so the cooler would be pre-cooled and ready to receive the ice cream. The ice cream was in fine condition and so was the cooler, so I loaded it in.

Then I noticed I still had a lot of dry ice left. What should I do with it? I was a rather conservation-minded person, and I reasoned that if I put the dry ice in with the ice cream, then the refrigerator wouldn't have to work so hard to keep the ice cream cold and we would save the state some electricity. So that's what I did.

It didn't occur to me that dry ice is much colder than the optimum serving temperature of ice cream (-108.4 º F compared to +10 º F – I just looked it up) or that the quantity of dry ice I was putting in might be more than enough to last all night.

Next day, at serving time, the ice cream was rock hard. There was no way you could get a scoop into it. We improvised. For a while we tried hacking off chunks of ice cream with a butcher knife, but even that was hard work, and there was some risk of losing fingers. Fortunately Sunday was also a hot day, and we took full advantage of it. The method we finally evolved was to remove each block of ice cream from its package—it came in rectangular half-gallon boxes—and set it in the sun until the surface softened up a bit, then we would scrape off what we could. It was messy, but we got the job done. And the crowd that came for free ice cream was amazingly patient.