I always wanted to try this (put dry ice in water) and last year I got the opportunity. When I bought some meat from Donald Russell it was delivered packed in dry ice (frozen CO2) i.e. solid carbon dioxide. This dry ice was used to keep the meat cool in transit. The meat and dry ice are transported in a polystyrene box which provides lots of insulation. However the heat does percolate a package like this and the dry ice sublimates, but usually there is some left on arrival. If not the meat temperature may rise too high. So I had a source of dry ice.
The first thing I wanted to do as soon as the meat was stored in a cool place was put the dry ice in water and watch it bubble away and the vapour flow out and down the side of the container. I caught it on video below:
“Oh dear! My quarter full tin of paint, for hardwood windows, was resting on a sheet of cardboard when a gust of wind lifted the cardboard and tipped over my paint pot.”
The spilt paint on my patio slabs created a 20cm mahogany puddle with splashes around it. There would have been photos but I had to swear first and then get on with cleaning it up.
How I Cleaned Up The Spilt Paint On My Patio
I began the clean-up process of removing the spilt paint on my patio without delay, before the paint puddle spread out or started to set. This is how I dealt with it. I went and got a roll of paper towels (a kitchen roll) and ripped off two sheets still joined together. I folded it double and with both hands I scooped it towards the middle of the puddle from the far side, then with more paper towels I scooped it towards the middle of the puddle from the near side leaving the tissue in the middle to soak it up. I then used more paper towels to pick up the messy towels and take them to the refuse bin. I then repeated this doing it in a way that would not spread the pint outwards. I always moved the paper to the middle of the puddle. Then I cleaned my hands so that I didn’t spread it around.
After I had removed a lot of the paint I poured paintbrush cleaner (the variety that can be washed off with water) on the remaining paint puddle and the splashes. I then used a hand-held scrubbing brush to work the paintbrush cleaner into the paint. I added more paintbrush cleaner and I could see it washed the slab where I had poured it so that I could see the concrete colour showing through. This was a good sign that the paintbrush cleaner was working to dissolve and remove the paint. By this time several slabs looked to be in a terrible state, but having done this before (using paintbrush cleaner to remove wet paint from concrete) I knew that the time had come to hose it all away.
I did just that. I washed this area of my patio with clean water from a hosepipe. The paintbrush cleaner went milky, as it does when mixed with water, but after plenty of water was used the patio was as clean as it was before the paint was spilt.
My only remaining problem was – the hosepipe had splashed the window I had just painted, doh!
It seems the Google job interview process requires a problem to be solved. I’ll take this hourglass problem, “Using only a four-minute hourglass and a seven-minute hourglass, measure exactly nine minutes.”
Solution Principle: Use one hourglass to measure out a smaller amount of time on the other hourglass. Repeat until you have the correct time periods stored in each hour glass such that when you add their times together by turning the second one up when the first finishes you get the correct total time of nine minutes. Continue reading “Google’s Employment Applicant’s Hourglass Problem”
NOTE: The article quotes, “….with the blackness of space and the bright curve of Earth providing a stunning backdrop.” However, if you watch the video carefully you will see as the balloon ascends and the horizon moves across the scene that the curvature of the earth varies from being convex to concave. This suggests to me that the camera lens has a lot of distortion and so it cannot be relied upon to give a good impression of the curvature of the earth.
Doesn’t paper folded enough times create a stack that reaches to the moon? Well it doesn’t here. However you would need a suitcase to carry it around if you wanted to protect yourself against being taken short. (It is toilet paper after all.) The students at St. Mark’s School in Southborough, Massachusetts asked how many times can you fold paper? They went on to break the record. See below: