Beth Sylvia sat on her knees stacking multiple sieves that looked like round cake pans with mesh bottoms.
Then the geologist from the Maryland Geological Survey poured a sample of sand from Ocean City over the top.
"Let's see what happens," she told 9-year-old Cullan Asher, who watched as Sylvia shook the sieves, causing the finer grains to fall to the bottom pan while the larger, rockier pieces remained in the top.
By distributing the different grain sizes, she explained, she can weigh the samples and analyze the make-up of sediment, including checking for possible contaminants.
The demonstration was part of a Saturday event at the Columbus Center at the Inner Harbor to introduce kids into different science careers. The event was held in conjunction with the Geological Society of America's annual conference, which is being held in Baltimore Sunday through Wednesday.
"We wanted to do something that was outreach-oriented… to give up an opportunity to show why we are excited about rocks and minerals and planets," said David A. Vanko, general chair for the society's annual meeting.
Cullan's mother, Pranoti Asher, and her husband are both geologists from Washington and were in Baltimore to attend the annual conference. She said it is important for the science community to engage the public outside of their field.
Otherwise, "how will we get the next generation interested?" she said.
Vanko agreed, saying it's important to reach children in particular because youngsters are naturally interested in the world around them, but might not get many opportunities to talk to a geologist or other scientists. Those interactions, he said, can inspire children to pursue a career in science.
Vanko, who also heads Towson University's Jess and Mildred Fisher College of Science and Mathematics, said the convention will draw 7,000 scientists from across the country to the Baltimore Convention Center, where talks and research presentations will be given.
On Sunday, Simon Winchester, author of the "The Map That Changed the World," will give a presentation at 4 p.m. about the first geological map, created in England 200 years ago by William Smith.
Many of the conference events are open to the public, and events Sunday include discussions of "urban geochemistry," a presentation on climate change and its effect on the Chesapeake Bay, and various exhibits . For details on the conference schedule, go to community.geosociety.org/gsa2015.
At Saturday's event for kids, there were not only geologists, but also scientists from the National Aquarium, the Maryland Science Center, NASA, the U.S. Forest Service, the Institute of Marine and Environmental Technology and other organizations.
Laura Lapham, an assistant professor at the University of Maryland Center of Environmental Science, was showing how remotely operated underwater vehicles — or ROVs — work in a large tank filled with water.
Lapham, who grew up in Florida, said she always had an interest in the ocean, but it wasn't until she took some oceanography courses in college that she decided to pursue a career in the field.
"It's really important to get [children] exposed to what we see in the ocean" and the jobs available, she said, not only to provide possible career interests but so they can be better environmental stewards.
Stacy Epperson brought her 8-year-old granddaughter, Jocelyn Smith, to the event because, she said, the girl is very interested in science and Epperson hopes to keep that interest alive.
She and Jocelyn looked over various rock samples from across the state at the Maryland Geological Survey table, picking up several of the samples. The Baltimore region, which sits between the Piedmont and Coastal plain, was represented by pieces with more sands, gravel and clay.
Epperson said she feels its important for parents to encourage their children to explore different science fields.
Girls, in particular, need someone to help nurture their curiosity, she said, or "it may never get developed."