Place the potato on a table top.
2. Hold the straw at the top (without
covering the hole).
3. Try to stab the straw into the
4. Next, hold your thumb over the
hole in the top of another straw.
5. Try to stab this straw into the
What happens ? -
1.) The open-ended straw bends and
only a little bit of the straw penetrates
2.) The closed straw (with your thumb
overing the top of the straw) cuts
deeply into the potato.
The air trapped inside the
straw gives the straw enough strength
to penetrate the skin of the potato.
As the straw enters the potato, the
potato plug compresses the air inside
the straw, increasing the air pressure,
and strengthening the straw.