Torque Demo

The hex head bolts fits an 8mm wrench.

Demonstrates the differences in torque when using a different sized wrench. For best results, hide the large wrench so that the students cannot see it.

Brag to the students how strong you are and say that no matter how tight any student tightens the bolt you will always be able to untighten it or even tighten it more to the point that the bolt head will shear off completely without any effort.

Challenge a student in class to come up and tighten the bolt as tight as they possibly can (using the small wrench).
After the student has tightened the bolt as tightly as they can, bring out the large wrench and demonstrate how using a large wrench you can easily loosen or tighten the bolt and even shear off the bolt head completely.