January 8, 2014
Have you ever wondered if someone could stand barefoot on a bed of nails? Well, wonder no more! This episode explores the pressure on your feet in that situation. It also introduces the idea of pressure and how that relates to pounds per square inch (otherwise known as psi).
Episode 3: barefoot on a bed of nails
Pressure = Force/Area
The pressure on my feet when I’m standing in shoes was found by taking my weight and dividing by the area of my shoes touching the floor. I used this graph paper to to find the area (the 1/2″ option worked well).
Pressure = 175 pounds/66 square inches = 2.7 psi
When I’m standing barefoot on the bed of nails the total area of all the tips of the nails holding me up is around 0.35 square inches (that was an average of smaller nail tips and larger ones…the nail tips are actually all about the same size but some seem to “poke” into your skin more than others because they are slightly different heights)
Pressure = 175 pounds/0.35 square inches = 500 psi!
As you saw, that was a little too much for my bare feet!
Determine how much pressure is on your feet when you are standing on your tip-toes. You’ll need to use graph paper to find the area. Let’s say that you have to be able to stay on your tip toes for at least 10 seconds for it to count (none of this rocking up onto the very ends of your toes for a split second kind of stuff!). Post your findings in the comments below. Good Luck….I hope you can stand the pressure;)