Well, I felt it was finally about time that our group of able scientists tackled some “goo.” And what better subject for our first goo than “non-Newtonian liquids.” As our G3 scientists learned, non-Newtonian liquids are substances that have the properties of both a liquid and a solid; in other words, depending on the conditions, a non-Newtonian liquid can behave like a liquid, or it will behave like a solid. But where did that strange name even come from?
Back in the 1700’s, scientist/mathematician Sir Isaac Newton first defined the properties of liquids. According to him, a liquid is a substance that will always take the shape of its container (think of how water will fill up the space inside a drinking glass). He also said that a liquid will have a consistent “viscosity” (a resistance to “flow” at any given temperature). That means that you can put a spoon into boiling water and stir it just as easily as if you put a spoon in a bowl of cool water. And if you poured a glass of water onto a table, you would have difficulty moving all of that water along to one side of the table with just a spoon – the water will continue to spread and fill up the space of its new “container,” the table’s surface.
But what about something like quicksand? Quicksand is actually an example of a NON-Newtonian liquid. If you remain very still in quicksand, you could very slowly move your hands and body through it because it would behave like a liquid. However, if you started to panic and thrash around in the quicksand, it would start to behave like a solid and you would have a very difficult time indeed trying to move through it! For our own non-Newtonian project, our G3 scientists were asked to create their very own “oobleck,” or “gooey glop.”
But before we actually made any of our own oobleck, our scientists saw some pretty cool videos that highlighted the very interesting and super weird properties of a non-Newtonian substance like oobleck. In this first video, we watched Steve Spangler do a science experiment on the Ellen DeGeneres show. They actually mixed 2500 lbs. of cornstarch with water in a cement mixing truck to create an entire pool filled with oobleck!
In another very cool video, we got to see oobleck come alive! This popular experiment is often called “monster goo.” With the right speaker/amps, you can literally make the oobleck transform into a more solid state and literally twist and turn and dance into the air…
Our scientists were very excited about diving into this first goo project. So we wrapped up the presentation and jumped right into the hands-on experiment. The recipe is simple enough:
- 2 cups of corn starch
- 1 1/2 cups of water
- food coloring (optional)
When mixed together in the right amounts, the corn starch and water form a weird, gooey glop that many scientists refer to as “oobleck” (named after a popular Dr. Seuss book, Bartholomew and the Oobleck). As our scientists discovered, you can slowly move your hand through the goo, but as soon as you try to exert more pressure on the goo (or move your hand quickly), it behaves more like a solid. Our scientists could literally punch the substance in one instant (like hitting a solid brick), and then in the next instant slowly let their hand sink into the goo. All of the scientists were armed with plastic spoons. If they stirred the substance very slowly, the spoon could move through the goo like it was a liquid; if they tried to stir very quickly, the substance behaved more like a solid and the spoon couldn’t move through the substance at all! Another fun demonstration was to scoop up a handful of the goo and very quickly roll it around in our hands, just like you would do if you wanted to roll something like Play Doh into a ball. And the goo literally became a solid ball. But the second we stopped rolling it in our hands, the substance once again became liquid goo and oozed through our fingers!
Many of the G3 scientists experimented with adding additional water and/or corn starch to the mix to see what would happen. When there was too much water in the bowls, the substance really just became a cloudy white liquid. But when more corn starch was added, the mixture once again achieved the right balance to become a non-Newtonian liquid. Some of our eager scientists even tried adding bits of paper towels and cleaning wipes to their mixes – even a small plastic crab names “Hermity”…curiosity is one of a scientist’s best qualities! 🙂
We had to end our day a bit earlier than usual due to the extra time needed for clean-up. Even with the help of lab coats, many of our scientists were coated from head to toe in our goo. Fortunately for us, it dried and could then be brushed off…so we took a brief field trip outside the library to shake ourselves off in the parking lot. But the mess was nothing that a vacuum, some floor scrubbing, and some laundry detergent couldn’t clean.
The goo was a lot of fun, but I think it’s time for us to tackle some more gadgets or gizmos at the next meeting of our minds. I wonder what we’ll be exploring next!…