Date: Fri 16-Apr-1999

Publication: Bee

Author: ANN

Quick Words:

Tim-Cawley-Middle-Gate-demo

Full Text:

Cold Science: A Demonstration At Middle Gate

(with photos)

BY ANN MARIE COHEN

Math/science coordinator Pam Fagan invited Tim Cawley, a product safety

manager at Union Carbide, to visit Middle Gate School earlier this week. Mr

Cawley demonstrated for Dot Weinblad's second grade class several science

experiments using liquid nitrogen.

The children were amazed that a fresh daisy could dry to flakes within seconds

and crumble to the floor, once treated with liquid nitrogen. Mr Cawley

explained that the same process commonly used to bottle spices called

cyrogenics, was used.

Superconductivity was demonstrated by a magnet floating above a ceramic that

was filled with liquid nitrogen. The children were told that the ceramic acted

like a mirror, pushing away and constantly repelling itself, so spinning was

the outcome. Or in scientific terms, Mr Cawley said," We're changing the

movement of molecules."

Mr Cawley's "wizardry" continued with a silver cup and a pair of tongs. Do you

think this would be a good sounding bell, he asked his young audience. As the

children made their predictions, a few were selected to hit the "bell" with

tongs. A thud was the resulting sound. Out came the liquid nitrogen and much

to the student's wonder the treated silver cup then produced a clear bell-like

sound! The cold of the liquid nitrogen enhanced the cup's vibration.

Mr Cawley bounced a ball around the room and asked the students if they

thought the ball would still bounce once immersed in liquid nitrogen.

Yes, no, maybe's were heard, while Ms Fagan and Ms Weinblad smiled as they

knew the outcome of this experiment. Mr Cawley once again illustrated the

change of physical properties by applying liquid nitrogen to the ball's

surface. The soft, rubbery ball became stiff and brittle, and shattered!

Earlier in the demonstration balloons were treated with liquid nitrogen. The

cold balloons were stuffed into a small, portable cooler. Once, heated to room

temperature they broke out of their confinement in the cooler, providing a

colorful and whimsical end to Mr Cawley's demonstration.