Here’s what I’m throwing down in this activity: many of us are teaching surface area and volume of rectangular prisms, but other than memorizing a set of formulas, our students are not getting a whole lot out of it. Of course, you can blame that obsessive focus we have on standardized testing for our compulsion to teach - test - move on to the next topic, but c’mon, you can do better than that, right? This is a short activity that you can do in one period that will not only help your students better understand the difference between volume and surface area, but will also give them a valuable finding to take away: stay away from crushed ice!
If you look at the standard textbook type problems about surface area and volume, they usually focus on lame things like wrapping packages and painting rooms. Right, like anybody besides Sheldon Cooper would calculate the amount of wrapping paper needed to cover a present? And really, what good is calculating that you’ll need 2.44 gallons of paint for that room if you can only buy it in whole gallons? And besides, if you follow the “rules of rounding” and buy 2 gallons of paint instead of 3, you’ll end up not having enough paint to cover the room (unless you like splotches on your walls....)
In this investigation, your students will use SnapCubes (or any other form of interlocking cubes you may have around) to build and compare different sizes of ice cubes, all with the same volume. They will see that different sets of ice cubes will have exactly the same volume, but different surface areas, thus cooling down the drinks at different rates. They’ll also see that using different sized cubes affects how long the drink stays cool and use those calculations to explain the advantages and disadvantages of using crushed ice in restaurants.
This is an excellent “hands on - minds on” activity to show that there is a logic behind how things get cooled down (and why your soda gets watery really quickly....)