2018 Engineering week Impossible challenge

[Ron Kulas]

Each year, my team celebrates Engineering week with a challenge. Its that time of year again which means its time again for the Impossible Challenge. This year’s impossible Challenge is to battle heat transfer and keep an ice cube from melting when it’s placed in a pot of boiling water.

We are tasked with building a vessel/container to hold an ice cube using household items.

To make it fair for everyone globally (since this is a global challenge), you will ONLY be allowed to use the items listed below. We know that ice cubes aren’t the same everywhere in the world, so you can use what-ever ice you have (of reasonable size).

Here is the list of the ONLY items you are allowed to use to construct your container that will hold your ice cube.























Use as many or few of the above listed items as you wish)

Tools used to test the container:









The test to see if you met the challenge: Place the container holding your ice cube in a pot of boiling water and start the timer. Your container has to fit in the pot, and it has to be completely surrounded by water (hold it down with something if it’s too buoyant). How long can you boil the container without reducing the ice cube to water? Time stops when you remove your container from the boiling water and does not include time spent unwrapping or opening the container so a access door or hatch to gain ready access to your ice cube is something to consider.

There has to be some amount of solid ice remaining when you open your container. If there is only water, you have failed (you have allowed your container to be in the boiling water too long) Reduce the time on your next try to see how long you can retain ice. When you reduce the time to a point that you have retained some amount of solid ice, that is your time. Do you settle for that of do you use what you have learned to improve your design to see if you can extend the life of your ice cube?

I'll use this space to detail the progress.

[Ron Kulas]

I think the smart money is on maximizing insulation while minimizing the amount of water used while still meeting the tenants of the challenge of having the container I make, both fit in the pot and be able to be submerged.

Of the limited list of available insulators, Styrofoam seems the best insulator because it contains a lot of trapped air and it is water resistant which will prevent hot water from migrating to the ice cube. With Styrofoam, Dry hot air will have to do the work of melting the ice cube. The down side is the buoyancy. A great deal of weight will be needed to keep the container submerged for the duration of the test.

[Ron Kulas]

I think the quality of ice will play a significant role in how fast the ice cube melts. I picked up an ice cube tray and made ice with my very hard (mineral rich) private well, tap water. The cubes came out very cloudy. They were full of air bubbles and because of how I froze it, they included more air than I want.

I did some research on how yo make higher quality (clear) ice using distilled water and then boiling that distilled water twice (allowing it to cool between boils). The next step in making clear ice is to insulate the top of the tray to prevent the ice from freezing from the top down (which traps the air bubbles and minerals and pushes them down as it freezes from the top)

I allowed the distilled water to freeze from the bottom up by raising the ice cube tray off the bottom of the freezer so cold air could reach the very bottom of the ice cube tray. When I took both types of ice cubes from the freezer for photos, the cloudy ice began to fracture, making audible cracking sounds when exposed to room temp air. The clear ice remained very staple. The results of the two methods of making ice can be seen below.



Now its time to make the container.

[Ron Kulas]

Here is the remaining ice after boiling it in prototype vessel #2 for 20 minutes. Based on the improvements I made, I think 30 minutes or more is achievable.

[Ron Kulas]

Im observing that exposure to boiling water and steam for such extended periods of time that the allowable materials of construction do not with do well. White glue and tape may do well for a few minutes but as I reach an hour, those fastening means degrade and delaminate. Im forced to use the aluminum foil to hold things together and seal from leaks. Also, due to the extended boil time there is a need to add water during the boil as water levels are boiled away. The most recent prototype was tested at 50 minutes with solid ice remaining. I will attempt an hour next.

[Ron Kulas]

I was forced to build a new insulated container for the ice cube challenge. It was in such poor shape and the foam pieces so warped and shrunken from several boils that it was limiting my boil time to retain solid ice.

I changed the design a little and the new insulated container performed even better. After 1 hr and 2 mins I still had 50% of the ice remaining. Perhaps 1 1/2 hours is a possibility???

[Ron Kulas]

Im perfecting the layering of the wrapping of the ice cube to trap the cold air. Yesterday I reached 1 hour and 50 minutes of boil time.

[Ron Kulas]

I built a new container and revised how I pack the layers. Im incorporating alternating layers of cotton and aluminum foil around the ice cube in a chamber carved out of the center of the foam block. The Ice cube itself is already wrapped first in wax paper and then aluminum foil. Im finding that these layers are insulating the cube very well. I increased the boil to to 2 hrs and 2 minutes and aborted the test due to camera battery and memory card limits. Next I will try for 2 hours and 15 mins.

[Ron Kulas]

Here is the results after boiling an ice cube for more than 2.5 hours.