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.

Cells in Motion

The Biomolecular Discovery Dome had it's first Maryland Day appearance in 2013. The 2013 Maryland Day marked the 15th annual event, with a record attendance of 105,000 visitors. 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 in an article on the Biophysical Society's blog or view the video Cells in Motion here.

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!

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)?

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.