Read about Michael Faraday. He thought deeply about magnets. He thought that the iron filling patterns around a magnet followed “lines of force.” He conceived of these lines as something material. His idea evolved into a more contemporary concept the “magnetic field of force” in which the lines are not material.
(Early physical theories imagined matter-like, fluid-like substances that carried effects: electric fluid, caloric fluid, ether, etc. All of these early theories have been abandoned, but sometimes people develop conceptions of heat, electricity, energy, etc. that can look a lot like the early theories. As we continue our study of energy, check your own conceptions and understanding.)
Look at the images from a google search (diagrams of lines of force around a magnet): https://www.google.co.in/search?q=diagrams+of+lines+of+force+around+a+magnet&es_sm=119&tbm=isch&tbo=u&source=univ&sa=X&ei=fQ43VayRAcPmuQTAuYC4Cw&ved=0CB0QsAQ&biw=1283&bih=617
Scientists have wrestled with understanding how something can influence something else that does not touch (action at a distance). Think of gravitational force, magnetic force, and static electrical force. Can you think of any other forces that “act at a distance?”
Discuss the following question with your partner. Write your expectations in your digital science notebook. Include a sketch graph–strength of force along the vertical axis–increasing going up–and distance between magnet and magnetically attracted object along the vertical axis–to the right they get farther apart.
How does distance affect the size of the magnetic force?
Take a look at the following photos.
closest–only a notecard apart
How do you think this technique would work? What do you think you would find?