Science 1 ACADEC

What phenomenon was observed when certain materials were rubbed together?

They could attract lightweight objects like feathers or slips of paper due to an invisible force.

What name did William Gilbert give to the mysterious force observed in rubbed materials?

The "electric force."

In what year did William Gilbert name the electric force, and what was he experimenting with?

In 1600, while experimenting with amber.

What is the Greek word for amber, and why is it important?

"Elektron"; it is the root of the word "electric."

How did knowledge of electric phenomena progress in the centuries following Gilbert's experiments?

Philosophers made various observations, slowly increasing understanding without knowing the underlying cause.

What ancient theory explained the composition of matter in Western thought for centuries?

The theory that all things are made of four elements: earth, air, fire, and water.

What is the definition of an element in ancient philosophy?

A fundamental substance that cannot be made of anything else because everything else is made from it.

Why are earth, air, fire, and water no longer considered fundamental elements?

Because they are made of substances that can be broken down further; for example, water is made of hydrogen and oxygen.

What tool do students use today to learn about the elements?

The Periodic Table.

Why are elements like hydrogen and oxygen still called "elements" even though they're made of smaller parts?

For historical reasons, even though we now know they are not truly fundamental.

What do all things on Earth consist of according to modern science?

Some combination of elements from the Periodic Table.

What does the word "atom" mean in Greek?

Indivisible.

What did some ancient philosophers believe about atoms?

That all matter was made of indivisible particles called atoms.

What was the opposing ancient view to atoms being indivisible?

That matter was infinitely divisible—capable of being divided into smaller pieces forever.

What is the current scientific belief about the smallest pieces of matter?

That we have likely found the point beyond which matter can no longer be divided, although it's possible even these pieces are made of smaller things.

Are scientists certain that the current fundamental particles are truly indivisible?

No, it's still a hypothesis that they might be made of even smaller components.

What role did Benjamin Franklin play in the founding of the United States despite never becoming president?

He helped draft the Declaration of Independence and promoted it in Europe, especially in France.

Why was Benjamin Franklin popular in France?

Because of his scientific work and inventions prior to his political involvement, including his experiments with electricity.

What is a Leyden jar?

A device that stores electricity and can deliver an electric shock.

What did Franklin call the mysterious electrical phenomenon he observed?

"Electrical fire."

What important discovery did Franklin make about electric charge?

Electric charge is conserved—it cannot be created or destroyed, only moved between objects.

How did Franklin safely test the idea that lightning is electrical?

He attached a key to a stand under a small shelter, not by holding it himself, and measured static electricity buildup from a thunderstorm.

What did Franklin's kite experiment ultimately prove?

That lightning is an electrical phenomenon.

What is Franklin's "electrical fire" actually, according to modern science?

It is electrically charged particles moving from atom to atom.

What are atoms composed of?

Three types of particles: protons, neutrons, and electrons.

What is a particle in physics?

A fundamental piece of matter of which everything else is made.

What is located at the center of an atom, similar to the Sun in the solar system?

The nucleus.

What two types of particles are found in the nucleus?

Protons and neutrons.

How are protons and neutrons similar?

They have nearly the same mass.

What is mass, and how is it measured?

Mass is a fundamental quantity of nature that determines an object's response to forces; it is measured in kilograms (kg).

How much is 1 kilogram approximately equal to in everyday terms?

About the mass of 1 liter of water.

What is the typical mass of an adult human?

About 60 to 70 kg.

What is another term for mass that refers to resistance to motion?

Inertia.

What is the third type of particle found in atoms, in addition to protons and neutrons?

The electron.

Where are electrons located in an atom?

Far outside the nucleus, orbiting around it, similar to how planets orbit the Sun.

What is the typical relationship between the number of protons and electrons in an atom?

Most atoms have an equal number of protons and electrons.

How many protons and electrons does a hydrogen atom typically have?

1 proton and 1 electron.

How many protons and electrons does a typical oxygen atom have?

8 protons and 8 electrons.

What defines an element on the periodic table?

The number of protons in its nucleus.

If an oxygen atom has an extra electron, does it stop being oxygen?

No, it is still considered oxygen because the number of protons defines the element.

Which atomic particle is most involved in electricity?

The electron.

What is the role of neutrons in electricity?

Neutrons play no role in electricity because they are electrically neutral.

What does the term "neutral" mean in the context of neutrons?

It means having no electric charge.

What kind of electric charge do protons and electrons have?

Protons have a positive charge, and electrons have a negative charge.

Do protons and electrons have the same amount of electric charge?

Yes, but the charges are opposite in sign.

What happens when two particles have opposite charges?

They attract each other.

What happens when two particles have the same type of charge?

They repel each other.

What force keeps electrons in orbit around the nucleus?

The electrostatic attraction between negatively charged electrons and positively charged protons.

If protons and electrons have the same amount of charge, why is electricity mostly about electrons?

Because electrons are much less massive than protons, making them easier to move.

What makes protons harder to move than electrons?

Protons are located in the nucleus and have much more mass, so they resist motion more due to inertia.

Why do electrons orbit the nucleus instead of the nucleus orbiting the electrons?

Because electrons have less mass and are more easily accelerated by forces, just like the Earth orbits the more massive Sun.

What does Newton's First Law of Motion state?

An object in motion will stay in motion (and an object at rest stays at rest) unless acted on by a net force.

What is inertia?

An object's resistance to changes in motion; related to its mass.

How is the strength of a force measured?

In newtons (N); one newton is roughly the weight of an apple.

What does Newton's Second Law of Motion state?

Force causes acceleration; more force means more acceleration, depending on the object's mass.

Why does the same force cause more acceleration in a small car than in a large truck?

Because the car has less mass, so it resists acceleration less.

What does Newton's Third Law of Motion state?

For every action, there is an equal and opposite reaction.

If the Earth pulls on the Sun with gravity, does the Sun pull back on the Earth?

Yes, with the same force, but the Earth accelerates more because it has less mass.

Why doesn't the Sun noticeably accelerate toward the Earth even though the Earth pulls on it?

Because the Sun has much greater mass, so the acceleration is minimal.

Do protons and electrons pull on each other with the same amount of electrical force?

Yes, because they have the same amount of electric charge, just opposite in sign.

Why do electrons accelerate more than protons when experiencing the same force?

Because electrons have much less mass (over 1,000 times less), so they experience greater acceleration.

What does the high acceleration of electrons cause them to do in an atom?

Electrons are flung around the nucleus, while the heavier nucleus remains mostly stationary.

What analogy helps explain why electrons move more than protons?

It's like a parent swinging a child: the child (electron) makes a bigger circle than the parent (proton).

Are protons and neutrons truly fundamental particles?

No, they are made of smaller particles called quarks.

Are electrons made of smaller parts?

As far as we know, no—electrons are considered truly fundamental.

What are quarks?

Quarks are the fundamental particles that make up protons and neutrons.

Why do scientists often treat protons as fundamental particles even though they are made of quarks?

Because in most situations, such as electricity and atomic behavior, this simplified model is accurate and useful.

What is the purpose of a scientific model?

To approximate reality and help us predict and understand natural phenomena.

Can a scientific model ever be proven 100% true?

No, we can only determine how useful it is in explaining and predicting observations.

What is scientific notation?

A compact way to express very large or very small numbers using powers of ten.

How is the number 2,000,000,000,000,000,000,000,000,000,000 written in scientific notation?

2 × 10³⁰

How is the mass of a proton (0.000000000000000000000000001 kg) written in scientific notation?

1 × 10⁻²⁷ kg

What does a negative exponent in scientific notation mean?

It means dividing by 10 instead of multiplying.

Why is scientific notation helpful in physics?

It simplifies calculations and unit conversions, especially in the metric system.

What does the prefix "kilo" (k) mean?

1,000 or 10³

What does "mega" (M) mean in metric units?

1,000,000 or 10⁶

What does the prefix "centi" (c) mean?

0.01 or 10⁻²

What does the prefix "milli" (m) mean?

0.001 or 10⁻³

What does "micro" (μ) stand for?

0.000001 or 10⁻⁶

What does the prefix "nano" (n) mean?

0.000000001 or 10⁻⁹

How many fundamental forces are there in nature?

Four

What are the four fundamental forces?

Gravity, electromagnetic force, strong nuclear force, and weak nuclear force.

What does the electromagnetic force do?

Attracts and repels electrically charged particles, holding atoms together.

What is the role of the strong nuclear force?

It holds protons and neutrons together in the atomic nucleus.

What is the weak nuclear force responsible for?

Particle transformation and radioactive decay.

What is gravity?

A force that pulls objects with mass toward one another.

What is the equation for gravitational force?

FG = G × (m₁ × m₂) / r²

In the gravitational equation, what does "G" represent?

The gravitational constant.

What happens to the gravitational force if mass increases?

The force increases; they are directly proportional.

What does it mean when two variables are directly proportional?

Increasing one increases the other by the same factor.

What does it mean if a variable is inversely proportional to distance squared?

As the distance increases, the variable decreases much more quickly—specifically, as 1 divided by the distance squared.

What happens to gravitational force if the distance between two objects doubles?

The gravitational force becomes one-fourth as strong.

If the distance triples, how much gravitational force remains?

1/9 of the original force.

What is an inverse square law?

A law stating that a quantity (like force or brightness) decreases proportionally to the square of the distance from the source.

What is a real-world example of an inverse square law besides gravity?

Brightness of light; e.g., Jupiter is 5 times farther from the Sun than Earth and gets 1/25th the sunlight.

What is the gravitational constant (G) and its value?

G = 6.67 × 10⁻¹¹ N·m²/kg²; it defines the strength of gravity in Newton's law of gravitation.

Why don't we feel gravitational attraction between people or chairs?

Because G is so small, the gravitational force between everyday objects is extremely weak.

Why do we mainly notice gravity from Earth?

Earth's large mass (6 × 10²⁴ kg) creates a force strong enough to overcome the smallness of G.

What is the gravitational force like at the atomic scale?

Negligible—masses of subatomic particles are so small that gravity between them is effectively zero.

What are the masses of a proton and electron?

Proton = 1.7 × 10⁻²⁷ kg; Electron = 9.1 × 10⁻³¹ kg.