We started this experiment very simply, by putting one drop of food coloring in cold water and one in hot. Simply put, the cold water is more dense than the hot water, as are other fluids such as air. When air warms it rises. This concept is responsible for what we know as convection currents found in weather and plate tectonics. The hot fluid moves up while the colder fluid sinks back down to get heated back up. This process keeps going and going and going.
When we saturated the water with salt, we made the water much more dense. It was almost so dense the solution could not hold anything else, not even one drop of food coloring, which is why it did not dissipate the way it did in the "pure" water solutions.
Next we then learned water and oil don't mix! Because they do not mix, scientists call them immiscible liquids. When we look at the glass with the water and the oil, the oil is on top of the water. This is because the one drop of oil weighs less than one drop of water. Scientists call this density and items that are less dense than water will float, those that are more dense, like salt, will sink.
To continue on with our experiment we poured salt in. It sank to the bottom taking some olive oil along with it. Remember, oil and water are immiscible so the oil returns to the top, which causes the movement within the solution.
All in all it is a great experiment and if you have not tried it, you should!
Sunday, July 14, 2013
the glory that is goo
We made two different types of goo on my garage creative blog. What exactly is goo and why is it so fun!? The first type we made has many different names for it. I like to call it oobleck because I love Dr. Seuss and there is a great story that can go along with making it.
It is called a non Newtonian fluid because it has properties of both a solid and a liquid. It has the liquid properties of taking the shape of whatever container it is in and is pourable. It behaves as a solid when pressure is applied to it.
Scientists also call it a colloid because the cornstarch is very small solid particles that are suspended in the water. It acts like a solid because when we touch it, we are applying a sideways shearing force to the water. Not familiar with that? Me either. What that means is when we touch it, the water moves away but the small particles of cornstarch do not. Think about trying to push sand out of the way on the beach.
While we made this non Newtonian fluid, there are plenty that we can purchase in the store. A couple of examples are jello, ketchup, barbecue sauce; what others can you think of?
The second goo we made acts a lot like flubber or silly putty. Unlike the oobleck, we can stretch it, bounce it, and tear it apart. This type of goo is called a polymer, which is a long chain of molecules.
Glue is made up of very long molecules. When we add the borax, it causes our molecules to stick together thus making a polymer!
Polymers are everywhere and have been used for a very long time.
It is called a non Newtonian fluid because it has properties of both a solid and a liquid. It has the liquid properties of taking the shape of whatever container it is in and is pourable. It behaves as a solid when pressure is applied to it.
Scientists also call it a colloid because the cornstarch is very small solid particles that are suspended in the water. It acts like a solid because when we touch it, we are applying a sideways shearing force to the water. Not familiar with that? Me either. What that means is when we touch it, the water moves away but the small particles of cornstarch do not. Think about trying to push sand out of the way on the beach.
While we made this non Newtonian fluid, there are plenty that we can purchase in the store. A couple of examples are jello, ketchup, barbecue sauce; what others can you think of?
The second goo we made acts a lot like flubber or silly putty. Unlike the oobleck, we can stretch it, bounce it, and tear it apart. This type of goo is called a polymer, which is a long chain of molecules.
Glue is made up of very long molecules. When we add the borax, it causes our molecules to stick together thus making a polymer!
Polymers are everywhere and have been used for a very long time.
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