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Name: Amanda
Status: student
Age: 16
Location: N/A
Country: N/A
Date: 2000-2001


Question:
If atoms have so much empty space in them, and humans are made up of atoms, why can't things pass right through us?


Replies:
Because that empty space is only "empty" of matter. Their are other things that call fill space. Among them are fields, electric and magnetic fields are common examples. In the case of atoms the space is filled with electric fields. All atoms have tiny positively charged nuclei surrounded by (relatively) large regions of space that are "filled" with a negative electric field from the electrons in the "orbits" about the nucleus. When something else tries to pass through our "empty space" the negative electric fields interact and prevent it from passing through.

To show that fields can prevent things from passing through empty space, get two strong magnetic fields and try to bring like poles together (e.g., north pole to north pole). Depending on your strength and the strength of the magnets you may be able to get them to touch but you will certainly have to work hard to do it. You will also notice that the closer you get them together the harder you have to work to get them closer.

Bradburn


Amanda: it depends what the 'things' are. Some things, like x-rays, can pass through us...other things, like a can of pop, can't. It all depends on their size and what type of 'thing' it is.

Katie Page


A more accurate answer is that the particles that make up our bodies and other materials can interact with each other through empty space. When you stub your toe on a rock, your toe does not actually touch the rock. Instead, it gets very close, close enough to transfer energy to it and experience force from it. At close enough distances, the rock and your foot repel each other. The force of the repulsion is enough to keep the toe and rock from passing through each other.

Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois



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