Maryland Day 2013

Maryland Day is an annual open house hosted by the University of Maryland. All across the campus, departments and organizations provide demonstrations, exhibits, and activities to show off all that the University of Maryland has to offer. The 2013 Maryland Day marked the 15th annual event, with a record attendance of 105,000 visitors

The Losert Lab participates in this event by hosting demonstrations about biodynamics and granular physics. Through the physics department, we offer activities designed to explore many interesting properties of sand and other granular materials. Through the biophysics program, we explore how cells move and why cells moving is important for our health.

Cells in Motion

The Biomolecular Discovery Dome had it's first Maryland Day appearance in 2013. Hosted by the University of Maryland Biophysics program, the 9 foot tall inflatable dome was busy all day showing movies on a range of biophysics topics. One of these movies, Cells in Motion, was organized in part by the Losert Lab. You can read more about the dome experience at the in an article on the Biophysical Society's blog. Cells in Motion is available for viewing below.

Can you push it?

How objects penetrate into granular materials is of interest to many people, including astrophysicists who study impact craters and civil engineers who test soil strength. If you push a shovel into beach sand, you will feel a strong resistance after reaching a certain depth. This is because when you push on the sand, strong contact forces between the grains are formed, which, in turn, push back on you. Here, we have two coffee cans, one of which has punched holes in its bottom. When the cans are pushed into the sand with equal force, which one goes deeper? The answer may surprise you!

Science of Sand

Will It Float?

Under certain conditions, such as avalanches and planet formation, granular materials are capable of behaving like a fluid. One way to ‘fluidize’ a pile of grains is to push it along its surface (this action is called shearing). In this experiment, there is a rotating disk at the bottom of the tank, which causes the pile of 3 mm glass spheres to flow in a rotational pattern. The fluid property that is of interest here is buoyancy, the tendency of an immersed object to either sink or float. When we place an object of high density (steel ball) on top of the flowing pile, does it sink or float? How about a lower density object (rubber ball)?

Science of Sand

Will it stick?

When you build a sand castle, you know to pack the sand as tightly as you can. Once the grains are close enough together, the sand undergoes a noticeable change. Instead of behaving like many flowing particles, it stands as a solid, yet fragile, structure. This transition is called jamming and is found in a wide variety of settings—from industrial storage and transport of granular materials, to glass production, to traffic on the Beltway. Here, we demonstrate jamming by showing you how to make a 'sand-cicle' using a soda bottle and a wooden plank.

Science of Sand

Can You Move Like a Cell?

This interactive demonstration invites participants to make and wear red hats while playing simple games. A camera above the participants tracks the red in each individual's hat as they move. While playing games such as follow the leader, participants can watch their motion live on a television screen. After the game is over, a scoreboard appears on the screen giving a readout of the group's overall speed as well as how collectively they were moving.

Collective motion is very important to cells. By following a leading cell, other cells may be able to more effectively find food or your immune system may be more accurate at detecting infection. In this demonstration, the scoreboard reflects how aligned the motion of participants was. When cells align and move collectively, they are able to grow baby animals and help heal wounds.

Move Like a Cell
University of Maryland

Contact

Please contact rmlee @ umd.edu for updates to this page (last updated August 16, 2013) and wlosert @ umd.edu for questions about the Dynamics of Complex Systems lab.