Awards, Grants, and Contests

Isaac Hernandez

Award: Top 100
Award: Honorable Mention for Thorough Reasoning

School: valhalla high school
Teacher: federico duay
Category: Contrived
Photo #20949

The weight of electromagnetism

This picture shows two magnets in equilibrium,  on top of a structure holding both with a scale reading its weight. A fundamental concept of physics is that weight is decided by the mass and the acceleration due to gravity downwards,  usually measured by placing the object on the scale. In plain site,  the second magnet on top is being repelled as to be floating above,  not having any direct contact with the structure,  at least in a stacking manner. At most you could describe the contact to be a horizontal contact that likely would only create a horizontal normal force relationship between the magnet and structure. Due to this,  at a first glance it is understandable to believe that the weight would be less because of the initial thought,  "It's not on the scale or attached to anything on the scale.. so it must have a lesser reading on the scale". This statement is disproved by physics.
  Whether or not the weight is stacked,  the reason as to why there's no change in the scale reading lies in the concept of force pairs. The magnets repel each other so that the bottom magnet repels the upper magnet,  and likewise the opposite. While the upper magnet is made to float by the bottom magnet,  the upper magnet repels the bottom magnet into the scale. This makes the bottom magnet relate a downward weight and the magnetic force from the upper magnet unto the bottom magnet. These forces combined equal the previous two magnet weights' reading,  creating no change in the scale reading.