• Question: What is weaker A. The gravity of the earth B. The electromagnetism of a human

    Asked by Ellen to Steven, Sarah, Lidunka, Jillian, Connor on 15 Jun 2015.
    • Photo: Steven Thomson

      Steven Thomson answered on 15 Jun 2015:


      Excellent question!

      The electromagnetism of a human is a hard thing to put a number on. Humans are (mostly) electrically neutral and (mostly) non-magnetic. The electric field generated by a human is almost zero, and the magnetic field generated by a human is almost zero. The individual atoms in our bodies might be electrically charged or generate magnetic fields, but overall there are as many positively charged particles in the human body as negatively charged particles, so they mostly cancel out.

      So I’d have to say the gravity of the Earth is a lot stronger than the electromagnetic force from a human. The Earth’s gravity keeps the Moon under control, after all, as well as all our satellites, so even though gravity is the weakest of all nature’s forces, in this case the Earth is so large that it’s stronger than the electromagnetic force from a person.

    • Photo: Jillian Scudder

      Jillian Scudder answered on 17 Jun 2015:


      Steven’s absolutely right that humans are electrically and magnetically neutral – we can’t levitate spoons with our fingers, or short out electrical machinery by touching it (thank goodness).

      That said, the electromagnetic force does hold our atoms together, and as much as the whole earth is pulling downwards on us, we still don’t go through other objects we’re sitting on! The atoms in our bodies are surrounded by electrons, and if you push two sets of electrons near each other, they repel, like two similar ends of a magnet. If the atoms within our bodies didn’t repel atoms in other objects so strongly, we’d go through our chairs, melt through the floor, and sink to the center of the earth! This atom-level repulsion is the electromagnetic force at work, and it’s much, much stronger than the gravity of the earth!

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