Pen, HOOP and the BOTTLE
Tony Wayne, Albemarle HS, firstname.lastname@example.org
laws of motion;
Law of Motion: “An object at rest remains at rest…”
· 12 inch diameter wooden embroidery hoop.
· “fat” tip marker
· Bottle. (Pictured is a plastic juice bottle with 4 cm
diameter opening at the top.
Be careful not to swing your arm and hit something or
One of the fun ways to present this is to be part magician. A magician uses misdirection.
Begin by balancing the hoop on top of the bottle.
Then balance the marker on top of the hoop. Tell the students you are going to
put the pen in the bottle without touching the pen or the bottle. Emphasize to
them that to watch the pen.
Swing you arm across the front of the hoop such that you grab the opposite side
of the hoop. Do it fast. The pen will drop in to the bottle. Have the students
to come up do the demonstration. Only demonstrate and tell them to grab the
near side –not the opposite side. When they grab the near side the pen will pop
up in the air. Then show them the real trick.
How the physics is demonstrated
This demonstrates inertia by the hoop’s motion. The hoop is grabbed on the near side. The hoop extends deforms by extending upwards. This pops the marker up. If the opposite side is grabbed, the hoop deforms by flattening itself. The pen then drops into the bottle. The hoop deforms because of the hoop’s inertia and flexibility. See the flash animation below for a slow motion look at what is happening.
and Tips Regarding the Demonstration
Sources & References
The embroidery hoops can be purchased at Walmart in
the craft section or at a craft store. Look for them near the embroidery floss.
They are less than $2.00 a piece -2004 price.
A special thanks to VASTfor hosting our web site.