Beachcombing

Ah, summer at the beach. What is your favorite beach activity? Swimming? Surfing? Volleyball? How about beachcombing? Do you like to collect seashells? Here is a brief guide to shells and other treasures you might discover on Virginia beaches. (To see the real thing, without a trip to the beach, visit the Science Museum’s exhibit, Beach Science: It’s a Shore Thing. The exhibit has labeled examples of most of these shells.)

Whelks are large sea snails; several species are native to Virginia. Knobbed Whelks and Channeled Whelks grow to 9 inches and, like most other whelks, have a right-side opening in their shell. Lightning whelks are similar but have a left-side opening and can grow to 12 inches. Whelks live in the sand in shallow water feeding on clams and other bivalves.

Atlantic Bay Scallop shells come in many colors, are ribbed and have “ears” near the hinge. This scallop lives in shallow waters along the southern Atlantic coast. Unlike other bivalves, scallops lie on the bottom rather than burrowing in the sand.

Angel Wings have a fragile white oblong shell and are found along the Atlantic coast south of Massachusetts. They burrow up to 2 feet in sand or mud and feed on algae through a siphon. Stout Razor Clams look similar but without ribs on the shell.

Arks are boxy bivalves with thick heavy shells that can tolerate rough surf. Several species live in the southern Chesapeake Bay, including the Ponderous Ark and Transverse Ark. Another species, the Blood Ark, is the only clam in the world with red blood.

Northern Quahogs or hard shell clams are usually gray, brown or white, can grow up to 4 inches and may live 30 years. Like Arks, most live in Virginia waters in the southern end of the bay. Native Americans used Quahog shells for wampum.

The Eastern Oyster has a rough gray or white shell and can grow to 4 inches. They attach to one another as they grow, forming dense reefs. Once so numerous that only the working classes would eat them, they are now greatly reduced in numbers.

This odd looking object is a Skate Egg Case. Skates, related to rays, are bottom-dwelling and lay their eggs in the sand. These egg cases, sometimes called “Mermaid’s Purses,” often wash up on Atlantic beaches.

Whelk egg capsules are attached together in a chain of 50-100. One end of the chain is then secured to the sea floor to prevent the eggs from washing ashore where they would dry out. The chain looks a bit like a lei and are sometimes called “Mermaid’s Necklaces.”



For more information, visit http://www.chesapeakebay.net/ and http://www.assateague.net/.  Thanks to both websites for these photos.

East Coasters Roasted by Heat Wave

By Ben Remo

Science Museum of Virginia intern

Residents of the east coast may have noticed an increase in heat lately. This increase has led to scorching temperatures of over 100 degrees. Most might be asking, how can this possibly happen? Why should we be subjected to such a hot summer? These dangerous, record breaking temperatures are caused by a heat wave currently hovering along the Atlantic coast. Last week, the northeast region experienced the worst heat wave in years.
At times temperatures have been above 100 degrees in some areas. New York City has opened over 100 cooling centers around the city providing relief from the heat for those who do not have access to air conditioning. Here in Central Virginia we have been subjected to temperatures around 100 degrees for days at a time.

How Heat Waves Work
Heat waves occur when temperatures are 10 degrees or above the normal averages in a region for a substantial period of time.
Ironically, heat waves do not mean that the earth is closer to the sun, a common misconception. According to National Geographic News, the week after 4th of July weekend, the earth was farther away from the sun than it will be at any other time this year. This is because the distance between us and the nearest star has little to do with the surface temperature here on earth.
The tilt of the earth on its axis has more to do with the occurrence of a heat wave. This is what makes for seasonal change. It is currently summer in the Northern Hemisphere because we are pointed towards the sun on the axis.
The formation of heat waves can be attributed to ridges of high pressure in the atmosphere that hang around the sky for some period of time. These ridges make the air hot and move clouds away, making the surface hotter. Clouds are a lot like oven mitts for the earth’s surface. The clouds act as a buffer between the surface and the sun just like oven mitts are a buffer between our hands and a hot object in the kitchen. When those “oven mitts” are not around, it makes for some hot days.

How to Stay Cool
OK. We know what causes heat waves; the next step is learning how to stay cool in the middle of one.
First, dress appropriately for the heat. With work that may be easier said than done. But on the weekends or after work, try to wear open toed shoes (no socks!) and loose, breathable clothes. When running the air conditioner, turn on all the fans in the house. It helps the cool air spread throughout the house. Next, go to the local pool or water park. While keeping you cool, a day at the pool is also good family fun. Drink cold water to stay hydrated. If you’re hydrated, you’re cool. Lastly, according to http://www.greenlivingonline.com/ ingredients in spicy foods actually cool you down after awhile. Add a marginal amount of peppers to any meal to cool you down on a hot day.

Global Warming?
Can a heat wave be attributed to global warming? That’s a sticky question. Global warming is climate; a heat wave is weather. The basic difference is time. Climate is long-term averages of weather, while weather is what’s outside right now. Some scientists believe global warming will change prevailing weather patterns to cause events such as heat waves, stronger hurricanes and even an extra snowy winter like the one just past. So the answer is maybe and maybe not. Scientists are studying both climate and weather trying to find answers. In the meantime, stay cool!

The Chesapeake Bay “Ouch” Forecast

Have you met Chrysaora quinquecirrha? If you’ve spent time in the Chesapeake Bay in the summertime, you probably have. His more familiar name is sea nettle, and he is not one of the most pleasant fellows you will ever meet. The sea nettle is a large sea jelly, a semi-transparent bell-shaped invertebrate with long stinging tentacles. Chrysaora quinquecirrha lives along the Atlantic Coast south of Cape Cod. Like many of us, he loves the Chesapeake Bay and its tributaries and can be seen in greater abundance here than anywhere else on the East Coast.
Getting tangled up with a sea nettle is not a fun experience. Those long tentacles contain thousands of microscopic nematocysts; upon contact the nematocysts fire a stinging filament into the victim. Sea nettle stings are not fatal but do cause a burning sensation and a painful rash. People often carry a bottle of meat tenderizer in their beach bags to counteract the sting, but plain vinegar works just as well. Vinegar prevents unfired nematocysts from firing thus preventing further discomfort.
Want to know how to avoid this unpleasant fellow? This summer NOAA is experimenting with sea nettle forecasting. Their website (http://chesapeakebay.noaa.gov/forecasting-sea-nettles) includes a map predicting the probability of encountering one, based primarily on water temperature and salinity. Sea nettles prefer water temperatures between 25° and 30°C (77° - 86°F) and salinity between 10 and 20 parts per thousand. Unfortunately for those of us who love it, the Chesapeake Bay is an ideal sea nettle habitat. So next time you head to the bay or the “Rivah” to swim or water ski, check out NOAA’s sea nettle prediction map. That way, you will know whether or not to pack the meat tenderizer.

Mastering the Science of Surfing

By Ben Remo

Science Museum of Virginia Intern

One of the coolest sports during the hot months of summer may look like nothing more than a balancing act. However, there is a lot more to surfing than just staying up. To surf is to master the waves and motion of the water. Here, we explain the science behind one of the most popular summer sports.
The first thing any good surfer must know is how waves are formed. As wind gushes over the surface of the water, friction causes the water to ripple. How big the ripples become is dependent on the strength of the wind, the distance the wind blows (also known as the fetch), and the length or duration of the gust. Waves are broken up into many parts, necessary knowledge for any good surfer. The crest is the very top of the wave while the trough makes up the valley in between two waves or the lowest point. Wavelength is the distance between two waves and wave height is the distance between a wave’s crest and trough.
Not all waves are good for surfing. It takes a little bit of science to make regular waves into surfer friendly ones. Surfers need waves that have a swell, or a smooth peak. These swells drag against the ocean floor, creating friction. This friction causes a wave to get taller and eventually break when they get close enough to shore. The best surfing waves are caused by a sand bank or reef on the ocean floor and by wind that blows from the beach out to the water. Winds that blow from the water to the beach cause choppy waves, the worst kind of waves for surfers.
To catch a wave, the surfer must paddle to gain momentum, hopefully enough so that the wave accelerates him/her forward. Ideally, surfers should catch the waves just as they are breaking. At this point, the waves are at maximum velocity. To catch a wave, the surfer’s velocity and the wave’s velocity must be the same. When the board is being carried along by the wave, the surfer can stand up. Once the surfer has caught the wave, staying on the board becomes the problem.
Balance is the number one skill any good surfer can have. To stay up, one must find the center of gravity. On a surfboard, the center of gravity is usually towards the back. The surfer must straddle the center of gravity. It is important that the person’s weight be more towards the back or the front of the board will dip into the water and eventually flip. The surfer controls the motion and direction of the surfboard by shifting weight from one side to the other. The sport is both challenging and fun when done properly. We leave you with a couple of tips for safe surfing. First, never let the board get between you and an on coming wave. Always wear a leg rope connected to the board because a loose board is always dangerous. Wear something to protect your chest and stomach from board rashes. When you come up to the surface of the water, locate your board immediately. Always surf with a buddy or make sure somebody has your back. Lastly, have fun and be safe. Also, check out the film The Ultimate Wave Tahiti in the IMAX®Dome featuring professional surfer Kelly Slater.