Scienze e Viaggi

THE THREAD TORSION

WHAT IT IS: it's a tool showing that charges of same sign repel.

HOW DOES IT SERVE ? To show that contrary charges attract each other and that same chargel repel in such way they bend the thread.

MATERIALS: two parallelepipedal pieces of wood, four small triangular pieces of wood, nylon thread, one small iron hook, two plastic straws, thick iron wire.

How do you make it? Nail the four triangular pieces of wood so that they make the rest for one of the parellelepipeds.

Nail the second parellelepiped to the first so that you have an upside down L structure. Screw the iron hook into the end of the horizontal arm. Knot one end of the nylon thread to the hook and fix the iron wire to the other end with a knot.

Shape the opposite end of the wire so that it can support one of the plastic straws.

How does it work? To achieve the thread torsion effect, first of all you have to charge the two plastic straws by rubbing them on a woollen cloth.

Place on of the straws on the shaped iron wire and bring the second straw close to it.
The Horizontal straw will be pushed away by the other straw causing the nylon thread to turn round. Th two straws repel because they have like charges.