1. The historical
development of the
concept of forces
BY: KIMBERLY KIMAK
PAP PHYSICS 2A

2. Gravitational force: Galileo

3. Gravitational Force: Johannes Kepler
 Johannes Kepler is best known for his laws of planetary motion.
This consisted of 3 laws of gravitational force. By 1618, Kepler had
announced all three laws. The first law: The orbit of every planet is
an eclipse with the Sun at one of the two focus points. The second
law: A line joining a planet and the Sun sweeps out equal areas
during equal intervals of time. The third law: The squares of the
orbital periods of planets are directly proportional to the cubes of the
major axis half the length of the eclipse of the orbits. These three
laws played such a prominent role in the development of the concept
of gravitational force which led to a scientist, Issac Newton to
expand on it.

4. Gravitational Force: Issac Newton

5. Electromagnetic forces
 Electromagnetic forces are the fundamental forces of
nature and are responsible for all the things we see. In the
19th century, we saw the 1st links between electricity and
magnetism. Charles Augustin de Coulomb advanced the
theory of electrical charges being mathematically
calculated. Later on Allesandra Volta discovered the first
method for generating electricity.

6. Magnetic Field
 Magnetism hadn’t been thoroughly explained until
magnetic induction was developed. Hans Oersted
discovered a magnetic field that had been caused by an
electric current in 1820. After his discovery, Andre
Ampere showed that parallel wires attract eachother if they
have currents in the same direction.

7. Michael Faraday
 Michael Faraday is a well known scientists, known for his huge
discovery of electromagnetic induction in 1831. He describes the
phenomenom that a changing magnetic field generates an encircling
electric field. This is known as Faraday’s law of induction. This law
was modeled mathematically by James Maxwell and later became
one of Maxwell’s equations.

8. Impact of Scientific Contributions
 James Maxwell extended Fraday’s findings. His theory was used to
explain how oscillating electric currents in wires produce
electromagnetic waves. Hertz then clarified the electromagnetic
theory of light in 1862. He was credited as the 1st person to
successfully demonstrate electromagnetic waves. His
accomplishments had far reaching consequences, like the
understanding of the nature of light.

9. Einstein
 Maxwell’s theory played a key role in Einstein‘s special theory of
relativity. The problem with Maxwell’s theory was that it was
invariant under Lorentz transformations but wasn’t invariant under
Galileo’s transformations. He solved the problem by deciding that
electromagnetism is more basic in physics and that classic
mechanics could be changed in a way so that it became Lorentz
invariant.

10. Continued…
 We use electromagnetic forces a lot and they are in our everyday
life. Some examples of electromagnetic forces are televisions,
vehicles, and radios. After Einstein’s theory of special relativity, he
explained the photoelectric effect. This later led to quantum
electrodynamics which deals with electromagnetism. These
electromagnetic forces are involved in nearly every interaction we
encounter.

11. Weak Nuclear Forces
 The weak nuclear force is the second weakest force, after gravity.
Ernest Rutherford made this discovery in 1899. He knew that beta
decay involved atoms emitting some type of particles. The following
year, Antoine Becquerel discovered that these particles were
electrons. In 1911, physicists found out that atoms lose more energy
of the electron that’s emitted. This finding led to new doors opening
because it suggested another outlet for energy in beta decay.

12. Strong Nuclear Forces
 In 1920, Rutherford discovered the Strong nuclear force when he
realized that electromagnetism should make the nucleus fly apart,
when protons are pushed away by positive charges of other protons.
He thought that the nucleus must contain electrons and those must
help hold the nucleus together.

13. Continued…
 This led to Wolfgang Pauli’s prediction of the existence of a new
particle without a charge in 1930. In 1933, Enrico Fermi
incorporated this particle into his history of beta decay. He showed
how electrons put out in beta decay don’t come from the nucleus’s
cloud of electrons around it. He also showed that a neuron decays
into a proton and gives out an electron( the electron has negative
charge while the proton has a positive charge.) With the help of Pauli
and Fermi, they created the Quantum theory.

14. Summary
 All in all, all these forces come hand in hand, and without
them, all the matter in the universe would float away. The
interactions of the forces are characterized by the types of
particles to experience the force, strength of the force,
range over which the force works, and the nature of the
particles that mediate the force.

15. Works Cited
 Electromagnetism.(2017). In Encyclopedia Britannica. Retrieved from
http://school.eb.com/levels/high/article/electromagnetism/106021
 “Kepler’s Three Laws.” Kepler’s Three Laws. Web.19 Nov. 2015.
http://www.physicsclassroom.com/class/circles/lesson-4/kepler-s-three-
laws
 Newton’s laws of motion.(2017). In Encyclopedia Britannica. Retrieved from
http://school.eb.com/levels/high/article/Newtons-laws-of-motion/55622
 “The Strong Nuclear Force.” The Strong Nuclear Force. Web.18 Nov. 2015.
http://aether.lbl.gov/elements/stellar/strong/strong.html
 “What is The Weak Force?” LiveScience.com. Web. 18 Nov. 2015.
http://m.livescience.com/49254-weak-force.html