Physics, in Layman's Terms Trivia Quiz

Answer: Gravity

Hopefully that question was an easy one to get you started. On our little blue planet a-twirling 'round the sun, gravity is the invisible force that gives weight to objects and keeps them grounded. On a grander scale, gravity orchestrates the dance of planets, stars, and galaxies in the vast cosmic ballroom.

Without gravity, things would get... well, a bit weird. Celestial bodies wouldn't orbit one another, and the universe as we know it (Earth, for example) simply wouldn't exist. One of the incorrect answers, air pressure, wouldn't be a factor since there'd be no atmosphere to begin with.

Interestingly, gravity is the weakest of the four fundamental forces. Hover a magnet over a paperclip. Watch how that tiny magnet outmuscles the gravitational pull of the entire Earth to lift the clip. That's electromagnetism. The other two fundamental forces, by the way, deal with the peculiar world of subatomic particles, and we'll just leave it at that. (And of course, you beat the gravitational force of the earth acting on the magnet by simply picking it up!)

Despite being the underdog of forces, gravity does stretch its influence across infinite distances, playing a crucial role in shaping the universe. From the birth of stars and black holes to the ongoing expansion of the cosmos, gravity's kind of a big deal.

One final cautionary note for the thrill-seekers out there. While gravity might be the weakest force, don't test that whole paperclip experiment near a black hole. When you're dealing with immense mass, gravity gets a bit aggressive.

Answer: The shape of the wings forces air to push up on the plane

Airplanes manage to stay in the sky thanks to the phenomenon of lift, a key force at play when their wings move through the air. Lift works against the pull of gravity, and it's all thanks to some pretty clever design and the physics of airflow.

The magic here lies in the wings' shape, called an "airfoil", which is specially designed so that air flows faster over the curved top surface of the wing than the flatter underside. Faster-moving air creates lower pressure (Bernoulli's Principle). This means there's less pressure above the wing and more below, and this difference generates an upward push, or what we call "lift". It's the same principle that makes a kite soar when the wind blows: the air rushing past creates lift, pulling the kite upward.

However, lift alone isn't quite enough to keep your plane from catastrophe. Thrust, generated by the airplane's engines, is also crucial. Thrust propels the plane forward, forcing air to move over the wings. As long as there's enough thrust to keep the air moving fast enough over the wings, and enough lift to counteract gravity, the airplane remains airborne. It's all about balancing the four forces of of flight: lift, gravity, thrust, and drag.

Answer: Your body wants to keep moving in a straight line

This sensation comes down to Newton's First Law of Motion, which states that "an object in motion will continue moving in a straight line unless acted upon by an external force." So, when a car makes a sharp turn, your body's natural tendency is to keep moving in the direction it was already traveling.

As the car begins to curve, the vehicle's structure (seat, seatbelt, door) exerts a force on your body, pulling it along the turn. However, your body is a bit stubborn and resists this change in direction. Initially, you continue moving straight (or outward, relative to the car's turn), which makes you feel like you're being "pushed" to one side.

The friction between your body and the seat eventually helps you move with the car, but that lag creates the leaning sensation we're all familiar with. If you're not wearing a seatbelt, inertia can hurt you a great deal, as can occur during sudden stops, like in a collision. When the car stops abruptly, your body still wants to keep moving forward at its previous speed. Without the restraint of a seatbelt, your body would continue its motion unchecked, which can lead to serious injury if the force of friction isn't enough to counteract inertia.

This force you feel when the car turns is often called "centrifugal force", but technically, it's not a real force; it's just inertia making you feel like you're being "pushed" outward.

Answer: Metal absorbs heat from your hand faster

This is all about the physics of heat transfer, specifically a property called "thermal conductivity". Metal feels colder than plastic because it's far better at conducting heat. When you touch a metal spoon, it efficiently pulls heat away from your skin, causing your fingers to lose warmth rapidly. Your body perceives this quick heat loss as "cold," even though both spoons are at the same temperature. It's not that metal is inherently colder. It's just more greedy about borrowing your body heat!

On the other hand, plastic is a poor conductor of heat, which is why it feels closer to room temperature. It absorbs heat from your skin much more slowly, so your fingers don't lose warmth as fast.

Thermal conductivity is essentially a material's ability to transfer heat. Metals like steel or aluminum have high thermal conductivity, enabling them to transfer heat rapidly. Meanwhile, materials like plastic, wood, or foam are insulators, meaning they conduct heat slowly and inefficiently.

The principle applies to other everyday experiences too. Think about walking barefoot through your home in winter: a tile floor feels icy cold compared to a carpet. This isn't because the tile is colder than the carpet (they're the same temperature) but tile conducts heat away from your feet much faster. Similarly, a metal spoon in hot soup feels burning to the touch for the same reason. It delivers heat to your skin just as efficiently as it steals it when cold.

Answer: Newton's First Law of Motion (Inertia)

This nifty trick, one my wife wisely won't let me try, works because of Newton's First Law, also called the law of inertia. This law states that objects at rest (like the dishes) will stay at rest unless a force acts on them. When you yank the tablecloth away quickly, the dishes want to stay right where they are due to their inertia.

The friction between the dishes and the tablecloth isn't strong enough (or doesn't last long enough) to overcome that inertia, so the dishes barely move... ideally.

It's like if you suddenly brake in a car. Your body lurches forward because it "wants" to keep moving at the original speed.

Answer: Cold air is denser because its molecules move slower

Hot air rises because its molecules move faster, spread out, and become less dense than cooler air. When air is heated, the energy makes its molecules zip around vigorously, taking up more space. This creates a lighter "packet" of air that floats upward, just like a balloon filled with helium (which is lighter than air) rises. Cold air, on the other hand, has slower-moving molecules that huddle closer together, making it denser and heavier, so it sinks.

Gravity plays a hidden role here: it pulls more strongly on denser, colder air, forcing it downward while the lighter hot air gets pushed up. This movement is part of convection, the process that drives weather, ocean currents, and even your oven's heat circulation. This is why heaters are sometimes placed near the floor (to warm rising air) and AC vents are high (to cool sinking air).

Answer: The air pressure outside the bottle is now greater than the pressure inside

At high altitudes, the air pressure is lower, so the air inside the sealed bottle expands to match that low pressure. When you bring the bottle down to sea level, the surrounding air is much denser (higher pressure), but the air trapped inside the bottle is still at that lower pressure. The result? The higher external pressure pushes inward on the bottle, causing it to collapse slightly.

Answer: The wall pushes back with equal force in the opposite direction

This is a great example of Newton's Third Law of Motion: "For every action, there is an equal and opposite reaction." When the swimmer pushes on the wall, the wall pushes back on them with equal force in the opposite direction, and that's what propels them forward. The wall doesn't need to move for this to happen; it just needs to provide resistance.

This is similar to throwing a tennis ball against a wall and having it bounce back to you. When you throw the ball hits the wall it applies force to it. According to Newton's 3rd Law, the wall pushes back on the ball with equal and opposite force. That's what sends the ball back toward you, the reaction force. (There are other things at play as well, such as conservation of energy and elasticity, but we'll just leave it there.)

Answer: Time moves slower for the astronaut

This is a mind-blowing effect of Einstein's Special Theory of Relativity called "time dilation". The faster you move through space, the slower you move through time relative to someone who isn't moving as fast.

For example, if an astronaut were traveling near the speed of light and returned to Earth, they would have aged less than the people who stayed behind. In extreme cases, years might pass on Earth while only months pass for the astronaut.

Answer: Light and particles can behave like both waves and particles

The double-slit experiment showed something truly bizarre. Tiny particles, like electrons or photons, act like waves when we're not watching them, but like particles when we observe them.

If you shine light (or fire electrons) through two tiny slits, instead of forming two simple lines behind the screen, the particles create a wave-like interference pattern as if they went through both slits at the same time. But if you watch which slit they go through, they suddenly stop acting like waves and behave like individual particles, removing the interference pattern.