Which 20th-century German-born physicist is considered the father of modern physics, thanks to his development of the general theory of relativity?
Albert Einstein
Einstein won the 1921 Nobel Prize in Physics for his work pertaining to the photoelectric effect (which helped lead to quantum theory).
Einstein is also known for his mass-energy equivalence formula E=mc2, which became the scientific foundation for nuclear fission.
Sound is measured in _____.
decibels
- 10 dB: silence;
- 60 dB: conversation;
- 85 dB: hearing damage possible;
- 120 dB: rock concert (front row);
- 130 dB: A baby’s cry
- 140 dB: hearing damage will occur without protection;
- 165 dB: jet takeoff
Which 20th- and 21st-century English physicist wrote the famous science nonfiction book A Brief History of Time in 1988?
Stephen Hawking
Hawking is renowned for his work on general relativity, black holes, and quantum mechanics, and was the Director of Research at the Centre for Theoretical Cosmology at the University of Cambridge.
Hawking suffered from ALS, a neurological disease that paralyzed him and ultimately claimed his life in March 2018.
What branch of physics deals with sound and waves?
acoustics
One practical application of acoustics deals with the design of buildings, such as concert halls and recording studios.
Recording rooms are designed to absorb sound, typically using a foam or cloth material. Concert halls, on the other hand, are designed to reflect and scatter sound.
Which 19th- and 20th-century Polish physicist was the first woman to win a Nobel Prize?
Marie Curie
Curie is best known for her research on radioactivity and the techniques of isolating radioactive isotopes.
_____ energy is the energy of an object in motion; _____ energy is the stored energy of an object based on its current state or position.
kinetic; potential
For example, a skiier has lots of potential energy at the top of a slope.
However, when they begin to ski down the mountain, that energy becomes kinetic due to their motion.
Which American inventor of the 19th and 20th centuries patented more than a thousand devices and aided in the development and design of numerous others, such as the incandescent lightbulb?
Thomas Edison
Other devices that Edison worked on or was influential in the development of include the phonograph, the motion picture camera, and power stations and generators.
Which American physicist of the 20th century is known as the father of the atomic bomb?
John Robert Oppenheimer
Oppenheimer played a major role in the Manhattan Project, which developed the first nuclear weapons.
What is the term used for electricity that flows in both directions and typically runs through our homes?
AC
(alternating current)
On the other hand, DC, or direct current, means that electricity only flows in one direction. This is the type of current that is produced by a battery.
Real world example: When you plug your cell phone in to charge at your house, the power cord transforms the alternating current running through your home to direct current that will charge your device.
Which 17th- and 18th-century English scientist played an enormous role in developing the modern understanding of calculus, light, motion, and gravity, among other subjects?
Sir Isaac Newton
Newton is considered one of the greatest scientists in human history.
A battery uses a _____ reaction to produce energy.
chemical
A discharging battery has a positive end (cathode) and a negative end (anode).
When the battery is connected to an appliance (load), a chemical reaction (between zinc, mangenese dioxide, and potassium hydroxide) occurs within the battery and an electrical charge is produced. This chemical reaction is called oxidation and reduction.
A battery eventually stops working when the chemical reaction can no longer continue.
Which American brothers and inventors built the first successful airplane and, in 1903, took it for the first sustained human flight in Kitty Hawk, North Carolina?
Orville and Wilbur Wright
(The Wright Brothers)
The Wright brothers subsequently developed their machine into the first practical fixed-wing aircraft and invented three-axis control, which remains the standard system of aircraft controls.
What sound is the result of an aircraft or other object breaking the sound barrier?
sonic boom
To break the sound barrier, an object must be going 768 mph (1,236 km/h) or faster.
A sonic boom is approximately 213 db and can shatter the human eardrum.
An object’s change in velocity (speed) over a period of time is its __________.
acceleration
This equation is typically expressed as: acceleration = Δ velocity / time. Acceleration is always given in units of velocity over time, such as m/s2.
For example, a car that goes from 0 to 100 kph in 10 seconds has an acceleration of 10 km/s2.
What is the significance of this number: 299,792,458 metres per second (or 670,616,629 miles per hour)?
the speed of light
This is the fastest that light can possibly travel, and is simply referred to as the constant “c” in physics.
“c” is often depicted as an estimate in scientific notation:
c = 3*10^8 m/s
Which 20th-century Danish physicist is best known for developing the model of the atom with a nucleus at the center and electrons orbiting around it?
Niels Bohr
Niels Bohr created the Bohr Model of Atomic Structure which showed that electrons traveled in defined circular orbits around the nucleus.
His theory lasted for a few years until physicists improved on his work using new principles of particle behavior.
He was also a contributor to both the Manhattan Project and the field of quantum mechanics.
Bohr won the Nobel Prize in Physics in 1922.
Organized into the Periodic Table, what is the name for a pure chemical substance consisting of a single type of atom?
element
The 118 elements currently known are summarized in the periodic table.
Which 19th- and 20th-century Scottish-American inventor is credited with the invention of the telephone?
Alexander Graham Bell
Bell devoted much of his research and career to elocution, hearing, speech, and the education of the deaf.
He also helped found the National Geographic Society.
Which 19th-century English scientist is most famous for establishing the notion of the electromagnetic field in physics?
Michael Faraday
Faraday is credited with discovering diamagnetism (which creates a magnetic field), electromagnetic induction, and the laws of electrolysis.
What kind of electromagnetic radiation does radar technology use to remotely detect objects such as aircrafts and severe weather?
radio waves
Radar was developed around World War II, and stands for Radio Detection And Ranging. Radio waves are emitted by an antenna.
These waves bounce off of (nearby) objects and are returned to the antenna, providing information about the distance and speed of the faraway object.
Sonar (sound navigation and ranging) works similarly to radar, but uses sound waves instead of radio waves.
Which Serbian-American inventor and engineer of the 19th and 20th centuries is noted for his contributions to the design of the modern AC electric power system?
Nikola Tesla
Tesla Motors is an automobile company named after Nikola Tesla.
Tesla’s AC engine design from 1882 was used for the company’s first vehicle, the Tesla Roadster.
What is used to measure the amount of matter contained by an object?
mass
Weight, on the other hand, is the force of gravity on an object’s mass (w = mg).
An object will have the same mass everywhere, but its weight may differ.
For instance, a person’s weight on Earth and on the moon will not be the same, because those environments have different gravity.
___ ___ proposed the law of universal gravitation.
Isaac Newton
Newton published his Principia in 1687, one of the most important works in the history of science.
His mathematically derived theories led to the development of calculus and physics.
Newton’s primary achievement was to take all the scientific advances of his day and tie them into a single united theory backed by mathematical proof, which was known as Newtonian physics.
Newton’s theory prevailed until Einstein developed his theories of relativity in the early 1900s.
