Finger Friction: Grip and Opening Packaging

Imagine the scene. Your 82-year-old neighbour, home from the shops, sits down to open a jar of marmalade. She can grip the lid, but no matter how much she turns it, she can’t get it to open. After struggling for some time, she decides she might have more success using a tin opener.

In 1994 there were 94,000 packaging accidents in the UK. This project reflects a desire not only to produce more inclusive packaging, but also to save the National Health Service the £12 million these accidents are reported to have cost.

By building a test rig, we were able to measure the static coefficient of friction against a number
of packaging materials. This represents a new area of research, as most existing studies have been driven by cosmetic companies, interested in dynamic friction coefficients that can give information on skin health and hydration. 

We then focused on the human torque required to open bottles and jars and compared male and female subjects from 20 to 80 years old. While those up to 70 would have no problem opening a jar (providing it was not greasy), women in their seventies would struggle to open it even in dry conditions.

The information provided by this project will be useful in designing packaging to take account of the growing proportion of the UK’s population that is over 50 and hopefully prevent nasty accidents with tin openers.