Dear Mr. Scientist,
This may seem kind of weird, but I always sneeze whenever I look at the Sun or some other bright light. Is this normal, and what’s going on?
—Colt T.
You are not alone! This strange quirk known as the photic sneeze reflex affects almost a third of the population. Although nobody knows for sure why bright lights affect some people in such a way; the best guess is that it has to do with crossed wires. Normally a sneeze is caused when an irritation in the nose triggers the trigeminal nerve, which lies very close to another nerve—the optic nerve. When the optic nerve senses a bright flash of light and sends a signal to the brain, some of this signal is also picked up by the trigeminal which mistakenly tells the brain there is an irritation in your nose and causes you to sneeze.
Dear Mr. Scientist,
What causes foam to form on the shores of bodies of water like oceans and lakes?
—Amber K.
This maritime foam is made from the dissolved organic compounds (mostly proteins and lipids) of dead sea life like algal blooms, plants or even fish. These compounds act as surfactants which lessens the surface tension of the water and allow air bubbles form at the surface of the water. When the water is mixed around by tides, currents, waves or boats, more and more bubbles form and stick together creating a foam. In large bodies of water, the wind will bring the small, floating pockets of foam together and create large collections of foam which wash up on shore.
Dear Mr. Scientist,
How do watches keep track of time using quartz? It’s just a rock, isn’t it?
—Carly J.
Quartz may be “just a rock” (it’s actually a mineral), but it also has the distinction of being piezoelectric. This means that when pressure is applied to a quartz crystal, it generates an electrical charge. Conversely, when an electrical charge is applied to it, the crystal will vibrate. By cutting a crystal to the right size and shape, it will vibrate at a specific rate (think of a tuning fork). These small vibrations will in turn generate small electrical signals at regular intervals which the circuitry in the watch uses to measure time.
Ask Mr. Scientist is written by Michael Leitch. If you have a burning science question you want him to answer, tweet it @DC_Science or email it to science@dailycardinal.com
