When everything clicks: UA professors provide simple explanations to confusing STEM topics

How sweat cools your body

"We know sweat is the body’s way of cooling you off – but how exactly does it work?  Once sweat is on the skin, it can evaporate (meaning it goes from a liquid to a vapor). The vapor contains more energy than the liquid so it has to get the energy – or heat - from someplace to become a vapor. This loss of energy cools your skin." 

Donald P. Visco Jr., Ph.D., Professor in Chemical, Biomolecular and Corrosion Engineering

Microrobots

"Microrobots are tiny little machines that can be programmed to carry medication to specific cells or even do surgery on a single cell inside our body. When I was introduced to the concept of microrobots and their size, I was asked to divide one meter by 1,000 to get a millimeter, and then divide it further by another 1,000 to get a micron – that is how small a microrobot is. That is a precise mathematical definition, but I prefer a more intuitive explanation. In another way, I ask my students to imagine that the size of a microrobot compared to our body is similar to the size of our body compared to the size of the State of Ohio. They get it right away. Then I tell them to imagine the places we can go in Ohio to explore. That is what a microrobot inside our body can do."

Amir Nourhani, Ph.D., Assistant Professor, joint appointment in the Department of Mechanical Engineering and Biomimicry Research and Innovation Center

Fractions in “real life”

"My students always tell me they will never use fractions in the real world.  I tell them that we live in a world of fractions. When you buy milk, you will probably buy a gallon or half a gallon for your cereal or to drink. You most likely will not drink the whole amount in one sitting – this is a fraction! Making a sandwich consists of two pieces of bread. Most loaves have 20 or 22 pieces of bread, so when you eat a sandwich you eat 1/10^th or 1/11^th of a loaf of bread. Think about pumping gas or even buying it, the price is in a fraction, and it’s awfully hard to pump a whole gallon of gas. We live in a world of fractions, so embrace the power that fractions give us in our choices every day."

Esther Wain-Weiss, Associate Lecturer, Department of Mathematics    

Relative humidity

"Have you ever walked outside during the summer on a 75 degree day and felt sweaty almost immediately?  What about when you went outside in the summer on a 75 degree day and didn’t really feel sweaty at all?  The difference in these two days is what’s called relative humidity. How much water the air can hold on any given day is a measure of the relative humidity on that day. When it is hot outside and the relative humidity is high, the air has a lot of water in it already. This makes it harder for your body to evaporate the water off your skin when you sweat (since the air already contains a lot of water). In many cases, it just builds up on the surface of your skin and you feel very sweaty!  On a day with a low relative humidity during the summer, your body is sweating much more effectively, and the water is evaporating off your skin to the air much quicker. You feel cooler."

Donald P. Visco Jr., Ph.D., Professor in Chemical, Biomolecular and Corrosion Engineering.

Trigonometry applications  

"Basic cell phone and GPS technology relies on trigonometry. When you use your GPS, your phone needs to know where you are. To do this, it receives signals from multiple satellites at the same time. The imaginary line to a satellite from the phone and between each satellite forms the sides of several triangles. The GPS technology uses these shapes and distances for trigonometric calculations in order to precisely pinpoint your location and where you want to go."

Esther Wain-Weiss, Associate Lecturer, Department of Mathematics    

Moment of Inertia

"The moment of inertia is a math calculation that determines how much load an object can take. Civil engineers need to know how strong beams, trusses, or structural elements are. I tell my students that the moment of inertia is a measure of stiffness. They need to understand this before they learn the math formulas used to calculate inertia."

Robert Bunnell, Professor of Practice, Civil Engineering