Coulomb's Law
Electrostatic forces are the attractive and repulsive forces between charged
particles. The French engineer and physicist, Charles Coulomb, developed
a mathematical formula to derive the magnitude of these forces based on
the size of the two charges and the distance between them. These electrostatic
forces are often referred to as coulombic forces. These are the forces
responsible for holding electrons and nuclei together in atoms, and for
creating ionic bonds between two oppositely charged particles or ions.
The strength of the coulombic forces directly influences the properties
of compounds formed from ions.
This program simulates the effects of ion charge and separation on coulombic
forces. Two ions are represented by spheres and the forces of attraction
and repulsion are demonstrated by arrows drawn from the spheres. One of
the ions (the blue one) can be dragged around using the mouse in order
to vary the distance between the two ions. In addition, the sign and magnitude
for each ion can be adjusted.
The distance between the two ions is reported in Angstroms at the bottom
of the screen. The 'Scale' in the screen gives an idea of the distance
on the screen. For comparison, one Angstrom = 10 pm = 0.01 nm
The relative strength and direction of the forces between the ions is
represented by "vector-like" arrows emanating from each ion. The length
of the arrow (measured from the center of the ions) is directly proportional
to the magnitude of the force (ie, proportional to the product of the charges
and inversely proportional to the square of the distance between them).
The resultant force is also given at the bottom of the screen in units
of Newtons (N).
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INSTRUCTIONS
- Adjust the charge of the draggable blue colored ion by clicking on the
up or down arrows. The charge can be set between -3 and +3.
-
Adjust the charge of the non-draggable red colored ion by clicking on the
up or down arrows, which again sets the charge between -3 and +3.
-
Alter the distance between the two ions by depressing the mouse button
on the blue ion and dragging it to a new location.
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