PhysicsLAB: Test Scenario: History of Matter

Refer to the following information for the next 22 questions.

Some important names (this list does not provide an answer to every blank)

Anderson	Fermi
Aristotle	Gell-Mann
Becquerel	Maxwell
Bohr	Mendeleev
Chadwick	Millikan
Copernicus	Newton
Coulomb	Pauli
Dirac	Roentgen
Einstein	Rutherford
Faraday	Thomson

1. In 1868, ________________woke up one morning and said "I saw in a dream a table where all the elements fell into place as required.” His table was arranged by increasing atomic mass. At that time scientists believed that the 80 elements listed were each made up of unique, indivisible spheres called atoms.

2. Roughly 30 years later in 1896 ________________make the 1st medical x-ray of his wife’s hand. Notice that her wedding ring can also be seen.

3. Also during 1896, ________________discovered natural, “spontaneous” radioactivity when some uranium salts produced a shadow of a Maltese cross on photographic film stored in the same drawer. This was alarming since the film had never been exposed to visible light.

4. In 1897, ________________discovered the electron. Prior to his discovery, scientists thought that the lightest known particle was the hydrogen atom. Since his electron had a mass that was roughly 1/2000 smaller than that of a hydrogen atom, he had discovered the first ______________ particle.

Since atoms were known to be electrically neutral, this scientist went on to propose the first “picture” of an atom known as the _______________ model.

5. In 1909, ________________ was able to obtain a measurement for the fundamental electric charge. Although his value does not agree with today’s accepted value of 1.602 x 10^-19 C, it was within 1%.

6. His investigation showed that every oil droplet carried a(n)_______________ of this charge. They concluded that this value was the charge on a single electron.

7. In 1913, ______________ published his mathematical atomic model in which electrons move in circular orbits that are located at specific distances from the nucleus and have distinct energy levels. His model is often called the solar system model.

8. In 1926 the _______________ model of the atom replaced orbits with electron clouds or orbitals. In this model neither the exact location of an electron nor its instantaneous energy or speed were exactly known – the only information available was just a probability of where an electron “might be.”

9. In 1928, ________________mathematically proposed the necessity for the existence of anti-matter.

10. Soon afterwards, in 1932, ____________ provided experimental evidence of anti-matter when he observed the track of a positron (a positively charged electron) within the cosmic rays that were moving through his apparatus.

Around 1932, Rutherford's assistant ___________ discovered that neutrons were released when Beryllium was bombarded by alpha rays. These penetrating, uncharged particles were tracked by Irene Curie when the beam struck paraffin and released protons.

11. During the 1950’s American physicist ________________restored order and elegance to the ever-increasing particle zoo. He proposed patterns that united the newly discovered particles with the already known particles of everyday matter. In 1968, at the Stanford Linear Accelerator, physicists used a high energy electron beam found experimental evidence that the proton was made of three objects with the correct charges confirming the ________________theory.

Today we use the Standard Model to organize the 12 indivisible particles believed to form all matter in the universe. The model also includes the bosons, or force carriers, for three of the four known fundamental forces.

12. List the four fundamental forces.

13. In the mid-1800’s ________________ experimentally united electricity and magnetism.

14. Later in that century, ________________ mathematically united electricity and magnetism “uncovering” the mathematical connection between electricity, magnetism, and optics – the speed of light.

15. In 1933, ________________ proposed the weak nuclear force as being responsible for natural radioactive decay. In particular, the decay of a free neutron into a proton, electron, and anti-electron neutrino. Today scientists are extending their knowledge of beta decay by investigating the energy distributions of recently discovered gamma rays that are also released in the process.

15 ________________, in his Theory of General Relativity, defined gravity as the warping of space-time. He predicted the existence of gravity waves that would be created when space-time was disturbed. He also stated that these waves would propagate at the speed of light. In 2015, gravitational waves were observed at two research sites in Washington state and Louisiana. The name given to this experiment is ___________.

16. In our everyday world, matter is primarily composed of 1st generation quarks and leptons. State the quark composition, including each quark’s charge, to yield the final charge of a proton and a neutron.

17. As you read the first three columns (across each row) in the table for the Standard Model from left to right, choose the property or properties that change(s)?

charge increasescharge decreasesmass increasesmass decreases

18. During the summer of 2012, scientists at the LHC experimentally uncovered evidence of the existence of the ________________. This result gave strong confirmation to the Standard Model by supporting the theory, developed 40+ years earlier, that had mathematically explained the unique mass of each particle and boson present in the table of the Standard Model.

19. How is Einstein’s equation, E = mc², used to analyze data from each and every experiment OR to design new experiments at the LHC? Include in your answer what each variable in the equation represents.

20. In 1948, _________ provided a pictorial representation of particle interactions on the subatomic level. These diagrams are used today to explain the bosons in a reaction involving the weak nuclear force.