Sci Kids

In the late 2000's, the museum partnered with the Richmond Times-Dispatch to provide a series of educational articles written by the museum's curators for elementary and middle school students.  Each "Sci-Kids" article explores a different scientific topic and correlates to the Standards of Learning. Many of the articles are as relevant today as they were then. With the permission of the Richmond Times-Dispatch, the museum has selected a variety of previously published articles and has correlated them to the most recent Standards of Learning. Happy reading and happy learning!

Published Articles

The Earth's magnetic north pole is on the move
Dr. James Beard, now retired, served as Director of Research and Collections and Curator of Earth Sciences at VMNH
2018 Virginia Science Standards of Learning: 2.2, 4.6, 5.8, 6.3, PS.11, ES.7, PH.7

For thousands of years, travelers have used compasses to help them find their way.

The magnetic needle in a compass points north. The needle is not pointing to the true North Pole, however, but to the magnetic north pole.

The Earth acts as a giant magnet, and the magnetic north pole is one end of that magnet. Unlike the true North Pole, the magnetic north pole does something strange -- it moves.

When it was first discovered in 1831, the magnetic north pole was on the mainland of northern Canada. By 1948, the pole had moved about 249 miles to the northwest.

Over the next 50 years, it continued to move north at an increasingly rapid pace. By 1999, it had moved north an additional 435 miles. By 2003, the pole was moving north at a rate of nearly 31 miles per year, a pace that continues today.

Why is the magnetic pole so restless? The answer lies deep within the Earth, in the liquid iron outer core. As the Earth rotates, the liquid iron swirls, much like water in a moving glass.

This swirling generates the Earth's magnetic field. As the currents and ripples in the swirling liquid core move around, the magnetic field changes and the pole moves.

You don't have to adjust your compass quite yet, but scientists predict that in 50 years or so, the magnetic north pole might be in Siberia!

Originally published August 23, 2007

Global cooling also has left its mark on Earth
Dr. Nicholas Fraser is the Keeper of Science at National Museums Scotland and former Director of Research and Collections at VMNH
2018 Related Virginia Science Standards of Learning: ES.2, ES.10, ES.11, ES.12

As we all know, climate change is the subject of intense debate. Extraordinary floods in parts of China, England and the U.S. have some people wondering whether the effects of greenhouse gases are beginning to take their toll.

While it is global warming that currently holds our attention, global cooling also has left its mark on our planet.

As glaciers move, they leave telltale signs of their presence, carrying and shifting huge boulders and scouring the land surface. Such evidence has been found in rocks that were set down in equatorial regions more than 650 million years ago. Some scientists believe the Earth was frozen at that time and refer to it as a Snowball Earth. Other scientists -- while not questioning the idea of glaciers at the equator -- express doubt that the Earth could be completely frozen over. Perhaps it was little more than a slush ball.

Just how did the Earth become so cold that glaciers covered land at the equator? If an increase in so-called greenhouse gases, such as carbon dioxide, in the atmosphere cause temperatures to rise, then a decrease will cause them to drop. The trick is in knowing what it requires to bring down the levels of these gases.

It turns out that if the continents lie around only the equatorial regions of the world, then rapid and unchecked weathering of the landscape occurs. This greater weathering process in turn absorbs carbon dioxide from the atmosphere. The decrease of carbon dioxide causes ice buildup, cooling the Earth even further by reflecting the sun's energy back into space. In other words, the system fuels itself and temperatures nose-dive.

We don't know for sure how the Earth broke out of this system, but it is likely there was an enormous and long-lasting increase in volcanic activity worldwide, spewing out carbon dioxide and methane gases, and the process was quickly reversed.

In short, scientists know how greenhouse gases can be reduced, but changing the arrangement of the continents is clearly something well beyond our ability and our desires.

Originally published August 9, 2007

Virginia climate used to be different
Dr. Nicholas Fraser is the Keeper of Science at National Museums Scotland and former Director of Research and Collections at VMNH
2018 Related Virginia Science Standards of Learning: 4.6, 6.3, ES.3, ES.7, ES.8

In Virginia, we are fortunate to have four very distinct seasons. Just when the rigors of ice and snow in the winter begin to wear thin, we notice the first gradual increase in the average daily temperatures.

Then just when the hot, sultry days of summer begin to take their toll, the advent of fall and its cooler, refreshing nighttime temperatures offer relief.

While this sequence is very predictable, the exact timing of the onset of each season is very unpredictable, as the recent cold snap during the Easter period reminded us.

The climate of Virginia has certainly not always been this way.

Two hundred million years ago, the area that we call Virginia was landlocked in the center of a huge supercontinent called Pangaea. All the present-day continental plates were joined together, but there was a large embayment of water on the east side of Pangaea that divided the supercontinent into northern and southern branches. This embayment is known as the Tethys Sea.

This configuration of the continents had profound influences on the climate. The flow of ocean currents between the poles was not impeded in the way it is today. As a consequence, warm equatorial waters flowed north and south so that there were no polar ice caps -- effectively this resulted in a greenhouse type of climate with elevated temperatures worldwide.

Just as importantly, the configuration of the giant land mass surrounding the Tethys Sea was conducive to the development of exaggerated monsoon seasons to the north and south of Tethys. This resulted in lush vegetation growth, sometimes in very swampy regions.

In some places, these plants died and were compacted ultimately forming layers of coal. The coal that used to be mined in the Winterpock region of Chesterfield County are a reminder of the very different climate in Virginia 200 million years ago.

Originally published May 3, 2007

Rivers that meander can form oxbow lakes
Dr. Alton Dooley is the Executive Director of the Western Science Center in Hemet, California and the former Assistant Curator of Paleontology at VMNH
2018 Related Virginia Science Standards of Learning: 3.8, 5.8, 6.6, ES.8

Certain streams and rivers, called meandering streams, tend to curve back and forth (or meander) as they flow across the landscape. For example, in Louisiana, the Mississippi River cities of Baton Rouge and New Orleans are only 75 miles apart in a straight line, but they are 135 miles apart if you follow the river.

Meandering streams are often accompanied by narrow, curved lakes called oxbow lakes (because they are shaped like the harnesses used to hitch oxen to a cart). Oxbow lakes can occur on either side of a meandering stream and are usually about the same width as the river.

Oxbow lakes only occur near meandering streams because they are formed by stream processes.

As water flows through a river channel, it moves at different speeds in different parts of the channel. If a river has a curve, the water on the outside flows faster than the water on the inside of the curve. River water contains a lot of silt and mud, but the water on the inside of the curve is moving so slowly that the silt and mud settle out, forming a point bar. However, the fast-moving water on the outside of the curve erodes the river bank.

This pattern of erosion on the outside and point-bar formation on the inside cause the curve to gradually get larger. Eventually, the curve is so big that it curves back on itself, and the river erodes a shortcut, making a new channel that bypasses the curve. This leaves the curve isolated as an oxbow lake, preserving the path the river used to take.

The size of an oxbow lake depends on the size of the river that formed it. One of the largest is False River, an oxbow of the Mississippi River in Louisiana. False River is 10 miles long and a half a mile wide at its widest point. Cut off from the river that formed them, oxbow lakes are temporary features. Eventually, they become marshes and finally dry up. This may take hundreds of years in the case of large oxbows.

Originally published May 17, 2007

SCI-KIDS: Jellyfish can put summer swimmers in a real jam
Dr. Judith Winston, retired Curator of Marine Biology at VMNH
2018 Related Virginia Science Standards of Learning: K.7, 1.5, 2.4, 3.4, 4.3, LS.7

Spring may be jelly-bean season, but summer is the season for jellyfish.

What is a jellyfish?

To start with, it's not a fish. That name just comes from the tradition of calling anything that lives in water a fish. The animals we call jellyfish belong to two groups of invertebrates: coelenterates, the phylum that includes corals and sea anemones, as well as jellyfish; and ctenophores or comb-jellies.

What we call a jellyfish is actually part of the animal's life cycle, the medusa stage. A medusa has a thick swimming bell, called an umbrella. On its underside are tentacles that the jellyfish uses to grab its food, sting and paralyze its prey, and then move it to the central mouth.

The name medusa came about because the tentacles under the jellylike umbrella reminded scientists of the Medusa of Greek mythology with her long, twisting snakes for hair.

The other stage of the jellyfish life cycle is a polyp. It has a tube-shaped body with one end attached to something on the seafloor. The other end has a mouth surrounded by tentacles.

Some jellyfish, such as the moon jelly, the stinging nettle and the cannonball jelly, have large medusa stages and tiny polyp stages; others have a larger polyp stage and tiny, short-lived medusas.

Moon jellies are harmless; but the stinging nettles that can become numerous in the Chesapeake Bay during the summer make swimming unpleasant.

It is not a good idea to go in the water when they are around. Stinging nettle jellyfish feed on comb-jellies, as well as small fishes, paralyzing them with poison from structures on the tentacles.

However, small crabs are sometimes found getting a free ride on the harmless upper side of the jellyfish's umbrella.

Originally published July 12, 2007

How animals find stored food
Dr. Nancy Moncrief is the Curator of Mammalogy at VMNH
Related 2018 Virginia Science Standards of Learning:  K.6, K.7, 1.5, 2.5, 3.4, 3.5, 4.3;,4.8, LS.6, LS.7

Many animals store, or cache, food when it's abundant so they can reduce the risk of starvation later, when food might be scarce.

Some animals, including bobcats and orb-web spiders, cache food for short periods of time -- hours or days. Others, including red squirrels, Eastern chipmunks, gray squirrels and blue jays, cache seeds for much longer.

Animals that cache food for a long time are called hoarders. There is more than one kind of hoarder. One type is a larder hoarder, such as the red squirrel and the Eastern chipmunk. These animals store large numbers of seeds in just a few places. Larder hoarders have to spend a lot of time and energy defending their caches so other animals can't steal them.

Scatter hoarders, including gray squirrels and blue jays, use a different approach. They store individual seeds, such as acorns, in many different places. This approach reduces the chances that another animal will find and eat all of the stored seeds. But an animal that scatter hoards must be able to find its many caches weeks or months after it has stored them.

How do gray squirrels find acorns after they bury them? For many years scientists thought that these squirrels simply used odor to locate buried acorns. This seems likely because most mammals have a keen sense of smell.

However, recent research indicates that odor might be just a part of the answer. There is evidence that gray squirrels can remember the exact locations of individual acorns long after they've buried them.

In a series of experiments, researchers tested the ability of gray squirrels to find acorns 12 days after they were buried in two types of cache locations: spots they had chosen and locations other squirrels chose. Jacobs reasoned that if a squirrel can remember its cache locations, it should be able to find its own more often than the caches of other squirrels.

On the other hand, if only odors are used to locate caches, a squirrel would be no more successful in finding its own than those of other squirrels.

The experiments showed that gray squirrels can remember exact locations where they bury nuts.

The squirrels in the experiments were able to locate nuts buried by other squirrels, probably using their sense of smell. But the squirrels found their own caches twice as often as those of other squirrels. The squirrels clearly remembered where they had stored individual nuts.

It's possible that gray squirrels use their sense of smell to find individual acorns, but only after using their amazing memories to return to their cache location.

Originally published March 3, 2009

Marine worms can look like flowers or peanuts
Dr. Judith Winston, retired Curator of Marine Biology at VMNH
Related 2018 Virginia Science Standards of Learning:  1.5, 2.5, 3.4, 3.5, 3.8, 4.2, 4.3, 4.7, 4.8, LS.3, LS.5, LS.6, LS.7, Bio.6, Bio.7  

Worms -- the ocean is full of them. Some you might recognize because they look like garden earthworms, but many look more like flowers, peanuts, or ruffles of ribbon. Some marine worms are microscopic in size. Others can be a yard or more in length.

"Worm" is our common word for invertebrate animals that have soft, elongated bodies. However, not all marine worms are closely related. They include representatives of several phyla, which are groupings whose members share a general body plan.

The flatworm group (Platyhelminthes) includes many free-living marine species, with very simple, flat bodies. They usually crawl along underwater surfaces, but can swim with a rippling motion of their bodies. In tropical waters, they can be brightly colored, often with beautiful patterning.

Ribbon worms (Nemertea) are unsegmented like flatworms, but they have a more complicated internal structure and are usually much more elongated. Similar to flatworms, ribbon worms can be brightly colored. The longest nemertean, the "Bootlace worm," is found on British seashores. It can grow to be 100 feet long, but is less than a quarter-inch wide.

Peanut worms (Sipunculida), get their name because when disturbed they contract into a lumpy peanut-shell shape.

Segmented worms (Annelida) include the oligochaetes, or worms with few bristles, such as the earthworm. In marine environments, polychaetes, worms with many bristles and varied appendages, are much more common than oligochaetes.

Fan worms and Christmas tree worms, whose flowerlike tentacles stick out of their tubes to feed on plankton, are part of this group. The clamworms and bloodworms used as bait for saltwater fish are polychaetes, too.

Worms are an important part of the food chain in ocean habitats. Some are deposit feeders, getting their nutrition from the microorganisms in the mud and sand they swallow.

Others are filter feeders, using ciliated tentacles to capture phytoplankton, while others eat seaweed, prey on other animals, or scavenge on dead animals.

Marine worms are also food for other marine animals, including many sport and commercial fish, making them part of the human food chain, too. Digging worms for bait has destroyed many habitats where worms and other animals live.

In some places, such as Australia, people have begun to farm marine worms for bait and as a good protein source for fish aquaculture.

Originally published February 3, 2009

SCI-KIDS: Toys long predated electronics explosion
Dr. Elizabeth Moore serves as State Archaeologist for Virginia and is the former Curator of Archaeology at VMNH
Related Virginia history and social science Standards of Learning: K.2, 1.3, 2.2, 2.3, VS.2, USI.3, WHI.2

I am frequently amazed at the variety of toys available in stores.

The explosion of electronics such as game consoles and remote-controlled vehicles, the quantity of dolls and their hundreds (if not thousands) of outfits and accessories. I was born at the end of the baby boom, not in the Stone Age, contrary to what my daughter thinks, and the contrast between what was available then and what is available now is astonishing. Which got me thinking -- what evidence do we have for toys in the Virginia archaeological record before European settlement?

I did some research on American Indian toys. There are historic documents that mention toys and games for children and adults. There are also observations made of Indian tribes across North America by explorers, anthropologists and settlers. These observations range from informal diaries and journals to museum and university-sponsored research projects.

We also can learn a great deal from modern tribes who have maintained many traditional aspects of their cultures for hundreds of years.

Some of the more frequently mentioned American Indian toys is the ring and pin game. There are many versions, but in the basic game a ring is tied to a cord. At the other end of the cord is tied a pin or thin stick. You hold the stick, swing the cord, and try to catch the ring on the stick. You can see versions of this toy in many toy stores.

Archaeological evidence of this game is found throughout North America. Common artifacts from one version are deer toe bones that have had a hole drilled through the length of the bone shaft.

Another game found in many Indian tribes is the wheel and dart game. A wheel or hoop is rolled, and the players try to throw darts or spears through it.

Stone spheres are also frequently found in archaeology collections. Balls can be used for any number of games, and it might be that these stone pieces were used for gaming by children and adults. Even today, balls are extremely popular and found in every culture.

Of course, there were undoubtedly many toys that leave no archaeological evidence. Corn husk or other plant-material dolls, balls made of hide, carved wooden figures or game pieces all would have decayed in the wet and acidic Virginia soils.

Children have always had toys, and this is a good time of year to remember that there are things common to all cultures.

Originally published January 6, 2009

We all can be champions of marine conservation
Dr. Judith Winston, retired Curator of Marine Biology at VMNH
Related 2018 Virginia science Standards of Learning: 4.7, 6.9, LS.7, ES.10

Aristotle, Jacques-Yves Cousteau, Charles Darwin, John Steinbeck, the Showa Emperor and Sylvia Earle. What did these famous people share?

At one time or another, they all shared the same research laboratory. This laboratory is so big that even had they all been working in it at the same time, there would have been plenty of room. The laboratory they shared is the ocean. All of them, at one time in their lives, were marine biologists.

Marine biology is the study of living organisms in the ocean, seas and estuaries (brackish water). It is a field almost as vast as the ocean itself. It covers every type of biology from ecology to taxonomy to molecular genetics, providing the research involves a marine plant or animal.

Aristotle, the ancient Greek "Father of Natural History," described more than 60 kinds of fish and marine invertebrate animals.

Jacques Cousteau, one of the inventors of scuba diving, also made films that popularized marine biology and conservation worldwide.

Charles Darwin presented his first scientific paper at an Edinburgh student natural history society, on his study of the larvae of the bryozoan Flustra (a microscopic colonial invertebrate).

The writer John Steinbeck collected marine animals with his friend marine biologist Ed Ricketts on a joint expedition to Baja California. Steinbeck later described his journey in a book, "The Log from the Sea of Cortez."

The Japanese Emperor Hirohito was a marine taxonomist, as well as a ruler. He published scientific papers on a group of colonial marine invertebrates called hydroids.

Sylvia Earle, perhaps best-known for setting deep-diving records, has studied seaweeds, as well as dolphins and whales. She also has been chief scientist of NOAA. In 1995, Earle published a fascinating autobiography, "Sea Change, a Message of the Oceans."

Our planet is 70 percent covered by ocean water. As Earle makes clear in her book, how we treat this part of our heritage, now and in the future, will have an enormous impact on our species and the planet.

Maybe we all can't become marine biologists, but we can be champions of marine conservation. And if you do decide to study marine life as a career, there's still lots of room in the lab. So come on in -- the water's fine!

Originally published December 23, 2008

Squirrels eat white acorns, but bury red ones for later
Dr. Nancy Moncrief is the Curator of Mammalogy at VMNH
Related 2018 Virginia Science Standards of Learning: 1.4, 1.5, 2.5, 2.7, 2.8, 3.4, 3.5, 4.2, 4.3, LS.7, LS.8, LS.9, LS.11, BIO.7, BIO.8

Many plants use seeds to reproduce. Plants can use wind, water or animals to disperse their seeds. This allows the plant to spread out its offspring so they can grow far away from the parent plant.

If seeds germinate near the parent, the offspring compete with each other and their parent for space, sunlight, water and nutrients. Offspring that grow away from other plants have a better chance of survival. Oak trees use animals to disperse their seeds. Oaks can be categorized into two major groups: red and white. The two groups have differences in their leaves and in their acorns.

The leaves of white oaks tend to have rounded tips, whereas leaves of red oaks tend to have pointed tips. Acorns of red oaks have more tannin (a bitter chemical) than white oak acorns. Acorns of white oaks germinate during early autumn. Acorns of red oaks remain inactive during the winter and don't sprout until spring.

Acorns are an important food item for many animals. Oak dispersal occurs when an animal does not eat the acorn immediately, but stores it in a place that is good for seed germination. Eastern gray squirrels often bury acorns for later retrieval. During autumn, the squirrels choose to bury either red or white acorns. Their choices depend on when they are planning to eat the acorns.

These squirrels often eat white oak acorns as soon as they find them. However, squirrels usually store acorns from red oaks so they can eat them during the winter or the following spring. There are several hypotheses to explain this behavior. Some scientists believe that squirrels choose to store the red oak acorns because of their high tannin content.

However, in an article published in American Zoology, two biologists state that the main reason squirrels store acorns from red oaks is not related to their tannin content. Instead, they conclude that red oak acorns are a better food item for the squirrels to bury because the natural winter inactivity of red oak acorns makes them less likely to decay in the ground.

The biologists also concluded that the primary reason that squirrels consume acorns of white oaks immediately is because they germinate in the autumn. As they germinate, white oak acorns grow a thick taproot that the squirrels don't like to eat.

Eastern gray squirrels eat a lot of acorns, but they recover only about 25 percent of the ones they store. This means that, for every acorn a squirrel buries and later digs up, it plants three acorns that can turn into new oak trees. This is a good rate of return for the oak tree and the squirrel.

Originally published December 9, 2008

Ear bones link whales to cows, paper suggests
Dr. Alton Dooley is the Executive Director of the Western Science Center in Hemet, California and the former Assistant Curator of Paleontology at VMNH
Related 2018 Virginia science Standards of Learning: 3.4, 3.5, 4.3, 4.7, 5.8, LS.3, LS.7, LS.8, LS.9, LS.11, BIO.6, BIO.7, BIO.8, ES.9

There has been much research over the past 20 years to try to determine the origin of whales.

Paleontologists have thought for some time that whales were descended from the artiodactyls, the group that includes living cows, deer and pigs, but no one was sure exactly which type of artiodactyl was most closely related to the whales.

A paper published recently in the journal Nature suggests that an obscure artiodactyl family called the Raoellidae might be the ancestor. Raoellids were small four-footed animals that lived in southern Asia about 45 million years ago. At first glance, they don't appear to have much in common with whales.

But when Hans Thewissen of Northeastern Ohio Universities College of Medicine and his colleagues examined one of the ear bones from a raoellid called Indohyus, they found that the bone had a thickened structure on one side, a feature called an involucrum.

The involucrum is an important structure. Whales have a very thick, heavy involucrum, which is a key part in allowing whales to hear underwater. The involucrum is only found in whales and dolphins; no other mammals have it (not even other mammals that live in the ocean).

The fact that Indohyus has an involucrum tells us that it must be closely related to the whales.

Originally published May 1, 2008

For worms, crayfish are perfect host
The late Dr. Richard Hoffman served as Director of Research and Collections and Curator of Recent Invertebrates at VMNH
2018 Related Virginia Science Standards of Learning: 1.5, 2.5, 3.4, 3.5, 4.2, 4.3, LS.3, LS.5, LS.6, LS.7, LS.8, LS.9, LS.11, BIO.6, BIO.8

At one time or another, most children have experienced the adventure of capturing a crayfish (often called "crawfish" or "crawdads") in a stream or pond. Picking one up by the body allows safe observation of the front legs with their menacing pincers.

Not all species live by choice in open water: In eastern Virginia the mud "chimneys" made by crayfish are commonly seen in low marshy places. Aside from their important role as predator-scavengers, crayfish deserve our interest for another reason.

They are the most important hosts for a group of segmented worms called branchiobdellids, which look like tiny leeches and for years were thought by scientists to actually be leeches. Their round, muscular body is made up of a headlike section, about 12 body segments, and a large sucker at its back end. By using its mouth and its back-end sucker, the worms can move rather like inchworm caterpillars.

There are about 150 known species, about a dozen of which are found in Virginia. The first member of this group to be noticed (on European crayfish) was found inside the gill chamber. While only a few species are found in such a strange habitat, 99 percent of all known branchiobdellids are ectocommensals, and move freely about on the crayfish, eating algae and small animals.

Some species are very specific about where they live. One can be found only on crayfish front claws, another only on the abdomen. Although free-living, these worms seem quite capable of evolving from simply living on another animal to enjoy food on the go, to becoming more complex as predator-parasites like their leech cousins.

Although the two worm groups are now seen as separate, they represent two similar lines of evolution in which leeches have moved ahead further because of their specialty: blood sucking. The next time you catch a crayfish, look at it carefully to find these small "guest" animals, which carry out their entire lives on the body of their host.

Originally published April 3, 2008

Oldest rock on Earth can be found in Canada
Dr. James Beard, now retired, served as Director of Research and Collections and Curator of Earth Sciences at VMNH
2018 Related Virginia science Standards of Learning: 5.8, ES.4, ES.5, ES.7, ES.9

The oldest rock in the world comes from one of the most remote places in the world. The rock is known as the Acasta Gneiss, and it comes from along the Acasta River in northern Canada.

The only way to reach the Acasta is by float plane or helicopter. In the early 1990s, scientists agreed that the Acasta Gneiss was almost 4 billion years old. This is nearly four times as old as the oldest rock in Virginia -- and not much younger than the age of Earth itself.

The rock is nothing special to look at. It has white, brown and greenish layers and clots. It looks a lot like rocks that can be found in many places, even in Virginia.

How do scientists know it is so old? Every rock contains a clock. This clock is in the form of radioactive elements such as uranium. Uranium atoms are unstable and waste away to turn into the element lead (just like the lead in car batteries or old pipes). About half of the uranium in a sample wastes away to form lead in 4.5 billion years (4.5 billion years is called the half-life of uranium).

By measuring the amount of uranium and the amount of lead in a sample, scientists can figure out its age. When they measured these elements in the Acasta, they found that not quite half of the uranium had become lead. Careful examination showed that the Acasta was 3.96 billion years old, the oldest rock on Earth.

Originally published July 26, 2007

Volcanoes are a notable part of Virginia history
Dr. James Beard, now retired, served as Director of Research and Collections and Curator of Earth Sciences at VMNH
Related 2018 Virginia Science Standards of Learning:  4.7, 4.8, 5.8; ES.5, ES.7, ES.8

Although there are no active volcanoes in Virginia now, they are an important part of our geologic history. Around the state, geologists have found lava and ash that has erupted from ancient volcanoes.

Some of the oldest lava flows in Virginia are found in the area around Mount Rogers. At Grayson Highlands State Park, visitors can see lava that is more than 700 million years old. This lava was very stiff and sticky. In some places we can see where the sticky lava has picked up rocks and soil as it flowed over them, just like your bubble gum will pick up sand if you drop it on the beach.

At Shenandoah National Park and elsewhere along the Blue Ridge, lava 550 million years old still contains many features seen in modern lava flows, including gas bubbles and "pillows" formed by underwater eruption.

Layers of volcanic ash are found in the sedimentary rocks of Catawba Mountain in Roanoke County. This ash spewed from volcanoes that may have been hundreds of miles away.

The largest volcanic eruptions in Virginia's history occurred 180 million years ago. These eruptions marked the birth of the modern Atlantic Ocean. Within 1 million years (and possibly less), eruptions covered not only much of Virginia but large areas of North and South America, Europe and Africa. The evidence of this huge outpouring of lava can be seen in many places around the state, including the Haymarket area of Loudoun County and along U.S. 460 near Farmville.

Monterey is home to a hill called Trimble Knob just outside of town. This hill is the eroded throat of one of the youngest volcanoes in eastern North America. This volcano and others nearby in Highland County and Harrisonburg are a mere 47 million years old.

Originally published December 27, 2007

Isotopes can provide historical information
Dr. Alton Dooley is the Executive Director of the Western Science Center in Hemet, California and the former Assistant Curator of Paleontology at VMNH
Related 2018 Virginia science Standards of Learning: 5.7, 6.5, PS.4, CH.2

There are 92 known naturally occurring elements. Each has atoms composed of neutrons, protons and electrons.

Elements are identified based on how many protons they contain. Atoms that contain only one proton belong to the element hydrogen (called element No. 1), while the largest atoms in nature, which have 92 protons, belong to the element uranium (element No. 92).

While all the atoms of a given element have the same number of protons, they can have different numbers of neutrons. Two atoms that have the same number of protons but different numbers of neutrons are called isotopes.

For most elements, it's possible to measure how much of each isotope is present in a rock or a fossil bone or shell. The amount present tells something about the history of the rock or fossil. For example, there are two common isotopes of element No. 8, oxygen: O16 and O18.

Seawater contains both of these isotopes, although O16 is much more common. However, the colder the water, the more O18 it contains. When a sea animal such as a clam builds its shell, oxygen from the seawater is included in the shell. Since cold water has more O18 than warm water, a clam that lives in cold water will have more O18 in its shell than the same species living in warm water.

By looking at shells of organisms that lived in the same place, but at different times, paleontologists can determine how temperatures changed in the past. This is one of the main sources of information about how the Earth's climate has changed, and the information is used to try to predict how the climate might change in the future. This is just one example of the many uses of isotope studies in geology and paleontology.

Originally published December 13, 2007

The short-tailed shrew is one fierce predator
Dr. Nancy Moncrief is the Curator of Mammalogy at VMNH
Related 2018 Virginia science Standards of Learning: K.6, 1.5, 2.5, 3.4, 3.5, 4.3, 4.8, LS.5, LS.6, LS.7, BIO.6

One of Virginia's most common mammals is the northern short-tailed shrew. You've probably never heard of this animal, and you may never have seen one.

Like many small mammals, shrews spend much of their time underground or under dense groundcover (to avoid predators), and they are very secretive. But if you live anywhere near grassy fields, damp woodlands or brushy marshes, these shrews live near you.

Shrews are not rodents, although they look a lot like mice. Short-tailed shrews have tiny eyes, small ears, pointed noses, pink feet and a short, pink tail. Their fur is gray and velvety, and many people (incorrectly) describe them as baby moles.

House cats frequently kill these shrews but don't eat them, probably because short-tailed shrews produce a foul-smelling, musky secretion.

Adult short-tailed shrews measure about 3¾ to 5½ inches from the tip of the nose to the end of the tail. So, in comparison to most familiar mammals (dogs, cats, people), these shrews are very small. When they are grown, these animals only weigh about one ounce. That's about as much as a slice of bread.

Like other shrews, short-tailed shrews have extremely high metabolic rates. Because of this, they must eat every few hours, so they are active day and night. In fact, the amount of food they eat each day is equal to their own body weight. Can you imagine eating your own weight in pizza? Every day of your life?

Short-tailed shrews are carnivores. They mostly eat insects and earthworms, but they can attack and kill animals -- including frogs and mice -- that are their size or slightly larger. This makes them one of the smallest and fiercest predators in Virginia. And they're probably living near you, but you didn't know it. Until now.

Originally published October 18, 2007

Doodlebug, the larva of ant lion, digs pit traps
The late Dr. Richard Hoffman served as Director of Research and Collections and Curator of Recent Invertebrates at VMNH
Related 2018 Virginia science Standards of Learning: K.6, 1.5, 2.4a, 3.4, 3.5, 4.3, LS.7, BIO.7

Spending a little time collecting live specimens and taking care of the captives, one can easily study the biology and life cycle of an interesting insect that occurs everywhere in Virginia.

Many people have heard of doodlebugs and some even know what they are. To find them, you should look for sheltered places where the soil is loose and dry: under highway bridges, eaves of outbuildings, and so on.

The doodlebug -- ant lion larvae -- dig small perfectly cone-shaped pits in the soil, and hide just out of sight at the bottom. Any small insect that stumbles into the pit slides down and is captured by the wide-spread jaws of the builder, which then sucks the victims' body fluids.

If you can find such a pit, (and often there may be many at one place), the occupant can be collected with a tablespoon slid quickly under the bottom of the pit, scooping up the insect along with the nearby soil.

The doodlebug is a short, dingy, hairy object with rounded abdomen and a small head with enormous, long jaws. When trapped on the surface, and prevented from digging itself back into the soil, it will usually scoot along backward with jaws spread.

If a small can or jar is filled halfway with loose soil taken at the capture site, and the doodlebug set free on the surface, it will quickly build a new pit by flinging the soil upward with jerks of its head. In no time, it will have created a new hideaway. If any prey tries to escape up the side of the pit, the ant lion will fling small headfuls of soil to knock it back down.

After several days or a week, the pit can become inactive even with the introduction of juicy bug morsels. If the spoon is again used to dig up the site, a small ball about the size of a thumbnail may be found. This is a case formed by the ant lion inside, in which it will undergo metamorphosis and become a winged adult, just as occurs in butterflies. This pupal stage can be returned to the soil, and a cover of gauze or screen wire placed on top of the container to keep the adult from escaping during the night and flying away.

The adult is an eye-catching slender animal with long lacy wings, normally active only at night and therefore hardly ever seen. It looks a lot like a damselfly, but the way in which it develops, with a pupal metamorphic stage, shows that ant lions are more closely related to butterflies and moths.

Not all doodlebugs dig pit traps. Many species are solitary hunters, wandering on the surface at night in search of small prey. We have more than a dozen species of ant lions in Virginia. Some are quite large with colorful wings and sometimes come to outside lights during the summer.

Originally published September 6, 2007

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