Magnetic field vs turns per metre in a slinky (varying L) - collect your own data

This video allows students to collect their own data when equipment is not available, or they have been away from school because of illness, covid isolation, floods, fire, and even if they have no time toperform their own experiment before the due date.

The experiment looks at the effect of changing n, the number of turns/metre in a solenoid on the strength of the magnetic field in the solenoid. This is done by changing L, the length of the solenoid, while keeping the number of turns constant at 50. The current is also kept constant at 2.0 A.

The solenoid is made from a steel edge-wound 'slinky' which can be adjuested in length from 20 cm to 70 cm in 10 cm increments. There are six variations of the independent variable (L) and each variation is replicated three times. That means there are 18 short videos contained within this presentation.

The aim is to experimentally determine the value of the magnetic constant mu-zero and to compare it to the accepted value. Hints are given about the process and safety is addressed.

I made a second video looking at B vs n in solenoids made from plastic sewing bobbins and wound with 0.25 mm enamelled copper wire in which the number of turns (N) is changed while keeping the length (L) constant. It can be found here:  

Dr Richard Walding, Griffith University, Brisbane, Australia.
Email: [email protected]