DANIEL CLIFTON • PICAYUNE EDITOR
MARBLE FALLS — The mixer, bags of marshmallows, a container of milk and assorted items scattered around Dennis Rose’s table at the front of the room make it clear this isn’t an ordinary trip to the library.
Rose, a retired Marble Falls High School chemistry teacher, darts around the front of the Marble Falls Public Library’s community room. His group of willing participants are elementary and middle school school students. They’ve come to learn what Rose is cooking.
“Science occurs around us all the time,” Rose tells the youth. “Our own bodies don’t work without science. It’s all physics, chemistry and biology.”
But it’s not enough to just talk about science. Rose decides it’s time for the kids to see it in action. So he turns to one of the most important scientific discoveries in human history.
The creation of ice cream.
OK, maybe it’s well down the ladder of importance compared to discoveries such as penicillin, electricity and gunpowder. But what parent is going to let their child grow mold on oranges, fly a kite during a thunderstorm or mix combustible materials in the kitchen?
Ice cream, however, presents an enticing scientific lesson complete with tasty (if done correctly) results.
After pouring a mixture of milk and sugar into sealable bags, which are then placed in larger bags with ice, Rose asks why the salt is necessary.
The kids ponder the question for a few moments, but none really offer an answer. Which brings up the crux of the entire workshop through the library’s “Science Rocks” program: thinking a bit more scientifically.
“What scientists really do is discover things that are already there and apply them,” Rose said. So there is no magic when salt is added to ice. It’s just simple science.
Left on its own, water freezes at 32 degrees. But Rose points out that it also melts at 32 degrees. The salt, Rose explains, lowers the freezing temperature of the ice just enough so it can help change the milk and sugar mixture into ice cream as the kids shake it.
And how does one verify this? Well, Rose offers one more scientific concept. With every experiment, scientists also use a control experiment in which they leave out at least one part of the plan. In the case of the ice cream, Rose makes up another bag of the ice and milk mixture but leaves out the salt.
“Let’s see what happens if we don’t use the salt,” he says. Of course, the ice cream doesn’t freeze.
The class, held July 16, wasn’t just about ice cream. Rose also led the kids through several other experiments, all with items commonly found in a kitchen.
One included dropping a part of a pipet wrapped with a little clay into a bottle of water. Rose demonstrated what would happen when somebody squeezed the water bottle.
The clay-wrapped pipet drops to the bottom of the bottle. But when the kids go through the steps, most of their pipets fail to do so. After several adjustments to the amount of air in the pipet or the amount of clay, Rose appears stumped. Then, he notices something. His bottle is different than the ones the kids have. His is more solid and sturdier.
So the kids begin to surmise, along with Rose, that the type of bottle affects the outcome of the experiment. Which is another part of science: looking at what’s happening, testing the hypothesis, adjusting the elements of the experiment if necessary and trying again.
“Science is all about asking why and then trying to figure it out,” Rose tells them.
The Marble Falls Public Library’s “Science Rocks” program continues July 23 with “Aeronautics” presented by Freedom Flyers and July 29-30 with “Sing and Sign.” The programs are 10 a.m. to noon. The library is located at 101 Main St. Call (830) 693-3023 for more information or to register.
In Burnet, the Herman Brown Free Library, 100 E. Washington St., is hosting “Ice Cream Science” on July 23 at 10 a.m. and celebrating Batman’s 75th birthday on July 30 at 10 a.m. Go to www.hermanbrownlibrary.org or call (512) 715-5228 for more information.