What type of celestial body, left over from the formation of our own solar system, is a rock-like object smaller than a planet?
Hundreds of thousands of asteroids are located in the "asteroid belt," a region of space between Mars and Jupiter. The largest asteroids are almost 600 miles in diameter.
Which 20th-century German-born physicist is considered the father of modern physics, thanks to his development of the general theory of relativity?
Although he won the 1921 Nobel Prize in Physics for his work pertaining to the photoelectric effect (which helped lead to quantum theory), he is best known for his mass-energy equivalence formula E=mc2, which helped lead to the development of nuclear fission.
What landmark historical event occurred on July 20, 1969?
On this day, the first humans set foot on the moon.
Three Americans were on this mission aboard Apollo 11: Neil Armstrong, Buzz Aldrin, and Michael Collins. Armstrong became the first man to walk on the moon, and made the iconic statement, "one small step for [a] man, one giant leap for mankind."
Sound is measured in ___.
- 10 dB: silence
- 60 dB: conversation
- 85 dB: hearing damage possible
- 120 dB: rock concert (front row)
- 140 dB: hearing damage will occur without protection
- 165 dB: jet takeoff
What is the difference between an atom, an element, and a molecule?
Atoms are tiny units of matter made of neutrons, protons, and electrons
- An element is a pure chemical substance consisting of a single type of atom (e.g. hydrogen, carbon, neon.) The 118 elements currently known are summarized in the Periodic Table
- A molecule is a group of two or more atoms held together by chemical bonds
Which 20th- and 21st-century English physicist wrote the famous science nonfiction book A Brief History of Time in 1988?
He is renowned for his work on general relativity, black holes, and quantum mechanics, and is currently 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. Hawking passed away in March 2018.
This branch of physics deals with sound and waves.
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.
What celestial body releases gas or dust and is made of ice and other materials left over from the Big Bang?
Comets can be seen from Earth, leaving a visible trail of gas and dust. This spectacle is commonly referred to as a meteor shower. It is believed that some of the organic compounds that make up our water and made early life possible traveled to Earth by comet.
Why does dry ice produce a smoky substance?
The smoke is the gaseous form of carbon dioxide.
The substance that we colloquially refer to as "dry ice" is actually the frozen form of carbon dioxide, and is about -100º F. When introduced to our surroundings, the carbon dioxide begins to melt. However, since it can only reach its liquid form in high-pressure environments, it changes directly from solid to gas.
Which 19th- and 20th-century Polish physicist was the first woman to win a Nobel Prize?
She is best known for her research on radioactivity and the techniques of isolating radioactive isotopes.
What was the first satellite launched by humans on October 4, 1957?
The satellite was launched by Russia and traveled for 92 days in space before burning up in the atmosphere upon its return. Sputnik has historical significance, as it led to the Space Race between the United States and Russia in a time where tensions were already high as a result of the Cold War.
___ energy is the energy of an object in motion; ___ energy is the stored energy of an object based on its current state or position.
For example, a skiier has lots of potential energy at the top of a slope. However, when he begins to ski down the mountain, that energy becomes kinetic due to his motion.
What is pH a measure of?
pH is a measure of how acidic or basic a substance is, ranging from 0 (most acidic) to 14 (most basic).
- Orange juice is acidic and has a pH level of 4
- Water is neutral and has a pH level of 7
- Bleach is basic and has a pH level of 13
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?
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.
What event, believed to have occurred 13.8 billion years ago, may mark the inception of our universe?
The Big Bang
The universe started in a small, dense, and hot state, then began expanding and cooling. Evidence for the Big Bang is found in the form of Cosmic Microwave Background radiation.
Which American physicist of the 20th century is known as the "father of the atomic bomb?"
John Robert Oppenheimer
He played a major role in the Manhattan Project, which developed the first nuclear weapons.
How do 3D glasses work?
3D glasses take advantage of humans' naturally existing binocular vision.
Traditional 3D glasses have one red and one blue lens. The movie actually projects two images, one red and one blue, resulting in the red image going to one eye (red lens) and the blue image going to the other eye (blue lens). This gives the illusion of 3D.
In electricity, what is the difference between AC and DC?
AC, or alternating current, means that electricity flows in both directions. This is the type of current that runs through our homes. 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 subjects including calculus, light, motion, and gravity?
He is considered one of the greatest scientists in human history.
Why does metal spark in a microwave?
Metal reflects the radiation rather than absorbing it.
Microwaves heat food using electromagnetic radiation, which freely passes through container materials such as glass and plastic. However, this radiation is not absorbed and does not pass through metal. Instead, it reflects, which can lead to damage to the microwave, electrical sparks, or fire.
How does a battery work?
Batteries use a chemical reaction to produce energy.
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 occurs within the battery and an electrical charge is produced. A battery eventually stops working when the chemical reaction can no longer continue.
Which 19th- and 20th-century Scottish-American inventor is credited with the invention of the telephone?
Alexander Graham Bell
He 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.
Why do boats and other large objects stay afloat in bodies of water?
These objects remain above water because they are less dense than the water they displace.
In chemistry, what is the difference between an element and a compound?
- An element is made up of only one type of atom (e.g. oxygen).
- A compound is made up of more than one type of atom (e.g. H2O: two hydrogen atoms and one oxygen atom form water).
Which wealthy Swedish scientist and arms manufacturer of the 19th century invented dynamite?
After his death, his fortune was used to establish the Nobel Prizes, awards for cultural and scientific achievement. Famous Nobel Prize winners include Albert Einstein, Marie Curie, and Martin Luther King, Jr.
In chemistry, what is the difference between ionic and covalent bonds?
- A covalent bond forms between a non-metal and another non-metal.
Ionic bonds result when atoms have an electrostatic attraction. An ionic bond forms between a non-metal and a metal.
Which 19th-century English scientist is most famous for establishing the notion of the electromagnetic field in physics?
He is credited with discovering diamagnetism (which creates a magnetic field), electromagnetic induction, and the laws of electrolysis.
How is laser light different from other types of light?
Lasers are brighter and more concentrated than regular light.
Lasers are produced by exciting electrons and directing them to project at the same time and direction, producing single-wavelength light. Low-power lasers are used in laser pointers and CD players. High-power lasers are used in nuclear fusion, to cut hard materials, and in certain surgical applications.
Which 20th-century American scientist and author gained widespread popularity for his 1980 television series Cosmos: A Personal Voyage, and its accompanying book by the same name?
Sagan was a celebrated astronomy researcher who studied the surface temperatures of Venus and the possibility of extraterrestrial life.
What is Newton's First Law of Motion?
An object at rest stays at rest and an object in motion stays in motion, unless an outside force acts on it.
Example: A ball rolling on the ground would continue to roll without stopping if it did not experience friction from the ground and the air.
What is Newton's Second Law of Motion?
Force is equal to mass times acceleration (F = ma); if objects with different masses are pushed with the same force, they will accelerate at different rates.
Example: If you push a brick and a cube of foam across the floor with the same force, the foam cube will accelerate faster because it has less mass.
What is Newton's Third Law of Motion?
When one object applies force to a second object, the second object applies an equal and opposite force to the first object.
Example: When two cars hit each other, the first car hits and applies a force. The second car then also applies that same amount of force to the first, in the other direction.
Which American brothers and inventors of the 19th and 20th centuries built the first successful airplane and achieved the first sustained human flight in Kitty Hawk, NC in 1903?
Orville and Wilbur Wright (The Wright Brothers)
They subsequently developed their machine into the first practical fixed-wing aircraft and invented three-axis control, which remains the standard system of aircraft controls.
How does a plane fly?
Planes are able to fly because of the airfoil shape of their wings.
This shape produces a difference in pressure between the top and the bottom of the wing, pushing the plane upward. This force is called lift. Keep in mind that lift is also produced by increasing the angle of attack (the angle between the flight direction and the chord line of the wing).
Other forces are acting on the plane, too. Thrust pushes the plane forward, typically via a propeller or jet engine. Drag slows the plane down through friction with the air. Weight pushes the plane downward due to gravity.
Which 16th- and 17th-century Italian physicist and philosopher proved that objects with different masses fall at the same velocity, and also discovered the moons of Jupiter?
He was a central figure in the Scientific Revolution and an early supporter of heliocentrism, in which the sun is the center of the solar system and the planets revolve around it. Galileo also made improvements to the design of the telescope and laid the groundwork for modern kinetics, dynamics, and astronomy.
This technology can remotely detect objects such as aircrafts and severe weather using 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 Greek-Roman philosopher of the first and second centuries A.D. authored several important and highly influential scientific treatises on astronomy and mathematics?
Ptolemy (90 A.D. - 168 A.D.)
How do we see color?
Humans have photoreceptor cells in our eyes that we call cones. When we look at an object, it reflects a certain wavelength of light. This wavelength is picked up by the cones in our eyes which transmit the signal to our brain, allowing us to recognize the color.
Name the six simple machines.
- Inclined plane
- Wheel and axle
Each of the simple machines has been around for thousands of years. They increase mechanical advantage, making work easier.
Why is the sky blue?
The sky is not actually blue, but it appears blue to us.
Sunlight allows all visible colors on the spectrum to be seen. Because blue and violet wavelenghths have the most energy, they scatter more, so what we see are those high frequency colors. The reason we see the sky as blue rather than as violet is actually because of our eyes. The part of our eyes that see color (cones) sees this combination of blue and violet as blue and white, causing us to view the sky as a light blue color.
This sound is the result of an aircraft or other object breaking the sound barrier.
To break the sound barrier, an object must be going 768 mph or faster. A sonic boom is approximately 213 db and can shatter the human eardrum.
Which American physicist is currently a professor of theoretical physics at the City College of New York, and has written popular books such as Physics of the Impossible and Physics of the Future?
He has become a pop culture science icon through his many books on the New York Times Bestseller list and as a host on channels such as The Discovery Channel and The History Channel.
An object's change in velocity (speed) over a period of time is its __________.
This equation is typically expressed as: a = 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.
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?
Also a contributor to both the Manhattan Project and the field of quantum mechanics, he won the Nobel Prize in Physics in 1922.
What is the life cycle of a star?
Stars form from clouds of gas and dust, called nebulae. Stars are made up mostly of hydrogen and helium, and they produce their own light and energy through nuclear fusion.
The life of a star depends on its size; large stars burn their fuel much faster, so they have shorter lives. As a star ages and cools, it will be categorized as a red star. The largest red stars are called red supergiants (1000 times larger than our sun), while the smallest are called red dwarves (1/10th the size of our sun).
Eventually the smaller red stars deteriorate into a planetary nebula until all that remains is the hot core of the star. The star is now a white dwarf. Larger stars experience a more violent end; eventually the star will explode, resulting in a supernova. Afterwards, all that remains is either a neutron star or a black hole. Neutron stars are dense, spinning clusters of neutrons. Black holes are dense beyond measure with a strong gravitational pull.
Which 15th- and 16th-century Renaissance Polish astronomer argued that the Earth moves about the Sun, displacing the Earth from the center of the universe?
He was one of the most prominent scientists of the time to support this belief about the movement of celestial bodies.
How does a telescope work?
A telescope is basically a giant magnifiying glass. There are two common types of telescopes: reflector and refractor.
Reflector telescopes use a mirror to collect, then focus, light. When you look through the eyepiece, it magnifies this image so you are able to see it clearly and with detail.
Refractor telescopes work in the same way, except instead of using a mirror, a lens collects the light and focuses it to form an image.
What is a vector?
A vector is a visual method that allows physicists and mathematicians to calculate an object's movement using both direction and magnitude.
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?
Tesla Motors is an automobile company named after Nikola Tesla. His AC engine design from 1882 was used for the company's first vehicle, the Tesla Roadster.
The rate that an object changes position over time is its __________.
Velocity and speed are often used synonymously, but there is a slight difference. Velocity is concerned with the object's change in position over time, so it is a vector term. Speed is concerned simply with the object's movement over time without respect to its original position, so it is a scalar term.
What is the difference between an object's mass and its weight?
Mass is a measure of the amount of matter an object has; weight 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.