Forces within the Atom





What is a force?

Any influence (PUSH OR PULL) that gives energy to an object, sometimes causing a change in the motion of the object.

We use forces in our lives every day . . . When you kick a ball, your foot makes the ball move by imparting a force on the ball. 







We recognize forces that occur when one object touches another, but can forces between two objects occur if they DO NOT touch? ? ? 




Forces, such as gravity and magnetism, pull falling objects (pine cones and leaves) towards the earth and push the like poles of magnets apart. 






So,What Forces Keep an Atom Together ?


·       There are four natural forces that are responsible for the behavior of an atom’s particles . . .




The Fantastic Four Forces within the Atom











·       A force that combines the effects of electrical charge and magnetism. The electromagnetic force can either attract or repel the particles on which it acts. Oppositely charged particles attract each other, while like particles repel one another.

·       Electrons are kept in the orbit around the nucleus by the electromagnetic force, because the nucleus in the center of the atom is positively charged and attracts the negatively charged electrons.






QUESTION—If all the protons inside the nucleus are the same charge and repel, what keeps them from bursting and exploding the atom? ? ?  How do they stay together? ? ?



THE STRONG FORCE—the greatest of the four forces!

·       The strong forces oppose the electromagnetic force of repulsion between protons. Like ”glue” the strong force keeps the protons together to form the nucleus.


·       The strong forces and electromagnetic forces both hold the atom together.








·       Weak forces are important because they are responsible for stabilizing particles through the process of radioactive decay, in which a neutron in the nucleus changes into a proton and an electron.





GRAVITY—mentioned last, is it the least?

Gravity is the force most familiar to us in our everyday lives—(apples, leaves, and planets)

·       Gravity is the force of attraction exerted between all objects in nature. Gravity causes apples and leaves to fall to the ground from the trees, as well as the planets to remain in orbit around the sun.

·        Gravity is most easily observed in the behavior of large objects.  Inside the tiny nucleus of an atom, the effect of gravity is small compared to the effects of the other three forces. Therefore, gravity is the weakest of the four forces!!!




What keeps the atom together? Who are the Fantastic Four?

The atom is comprised of three major particles—protons, neutrons and electrons.  There are four forces (Electromagnetic, Strong, Weak, and Gravity) that are responsible for the behavior of the particles and thus keep the atom together.