Pencil Through Wood

PIRA: 1F30.50

Overview:

When we launch the sharpened pencil through the wood, it does not penetrate the wooden board. This is because the board is able to act on the pencil longer than the unsharpened pencil. The unsharpened pencil is able to penetrate the board because the board is only able to act on the front of the pencil while it is traveling through the board.

Materials:

Pencil through wood apparatus

Launching tube, found in black tube for rods in outreach

Sharpened and unsharpened pencils, found in outreach bin F1

Wooden boards, found in outreach bin F1

CO2 tank, found in outreach

2x c-clamps

90° clamp

Table clamp

Metal rod

Setup:

Place the apparatus on a table with the open end facing away from the class, and use the c-clamps to hold it down. Put the table clamp on the side of the apparatus that has the hole for the launching tube. Place a wooden board into the vice in the apparatus. Place the metal rod into the table clamp and put the 90° clamp on the metal rod. Put the launching tube into the hole far enough to almost touch the wooden board and clamp it in place with the 90° clamp. Place the CO2 tank next to the launching tube.

How to:

Load a sharpened pencil into the end of the launching tube where we will connect the CO2 tank, and then connect the tank to the launching rod. Briefly squeeze the handle on the tank to fire the pencil. Replace the wooden board, and then load an unsharpened pencil into the launching tube. Fire the pencil.

Safety:

Make sure no one is on the open side of the apparatus when firing.