A piano.

Explanation: A piano has keys that play notes, but they cannot open any locks.

A cold.

Explanation: You "catch" a cold when you get sick, but you can’t physically throw it.

A bottle.

Explanation: A bottle has a neck (the narrow part), but it doesn’t have a head like a living creature.

A teapot.

Explanation: The word "teapot" starts with the letter "T," ends with "T," and holds tea inside.

Your age.

Explanation: Your age increases every year, but it can never decrease.

Rain.

Explanation: Rain falls from the sky when it precipitates, but once it hits the ground, it doesn’t rise back up in the same form.

A towel.

Explanation: A towel dries things by absorbing moisture, but in doing so, it becomes wetter itself.

A candle.

Explanation: A candle starts tall, but as it burns, it melts and becomes shorter.

A clock.

Explanation: A clock has hands (the hour and minute hands), but they cannot physically clap like human hands can.

A sponge.

Explanation: A sponge has many tiny holes, but its porous structure allows it to absorb and hold water.

A piano.

Explanation: A piano has keys that produce musical notes, but they don’t function as keys that unlock anything.

Footsteps.

Explanation: As you walk, you leave footprints behind you. The more steps you take, the more footprints you leave behind.

A bottle.

Explanation: A bottle has a neck, where the opening is, but no actual head like a living creature.

A comb.

Explanation: A comb has "teeth" to untangle hair, but it doesn’t use them to bite like an animal does.

An echo.

Explanation: An echo repeats sounds, but it has no physical form or body, and it is triggered by sound waves bouncing off surfaces.

Neither.

Explanation: Both weigh the same — a pound. The trick is in how the objects are described, but the weight is identical.

Your breath.

Explanation: While breath itself is weightless, it is difficult to hold it for more than a few seconds without exhaling.

A towel.

Explanation: A towel absorbs water as it is used to dry something, which means it gets wetter while the object or person it’s drying becomes drier.

A river.

Explanation: A river "runs" as water flows, it has a "mouth" where it meets a larger body of water, and it has a "bed" (riverbed) where it flows, but none of these things involve typical human actions.

Light.

Explanation: Light can illuminate a room completely, but it has no physical substance or mass, so it doesn’t occupy physical space like objects do.

A clock’s second hand.

Explanation: The second hand of a clock is always in motion, but it remains fixed to the center point of the clock face and doesn’t leave its axis.

Darkness.

Explanation: As darkness increases, the less visible things become. This highlights how absence of light impacts vision.

Silence.

Explanation: Silence is broken when any noise is made, including saying the word "silence," so it "disappears" when mentioned.

An umbrella.

Explanation: When it starts to rain (water comes down), people use umbrellas to shield themselves, which are raised up.

A black hole.

Explanation: A black hole is an area of space where gravity is so strong that nothing, not even light, can escape it. It forms from collapsed stars, but its "center" is a point of infinite density called a singularity, where "nothing" exists.

The cochlea.

Explanation: The cochlea is a part of the inner ear that detects sound vibrations and sends signals to the brain, but it isn’t shaped like an external ear.

A bubble.

Explanation: A bubble is filled with air, making it extremely light, but it pops with even the slightest pressure, so it can't actually be lifted by many hands.

The letter "v".

Explanation: This is a play on words; the phrase “center of gravity” literally has the letter “v” in its center.

Your age.

Explanation: Age always increases as time passes and never decreases, which is why it "comes up but never goes down."

Hydrogen.

Explanation: Hydrogen is the lightest element and is abundant in the universe, found in water, air, and stars, yet it has an almost negligible mass.

A table.

Explanation: A table has legs to stand on, but it doesn't move like a living being.

A river.

Explanation: A river "runs" (flows), has a mouth (where it empties into another body of water), and a bed (the ground beneath the water), but it doesn’t do these actions like a living creature would.

Your breath.

Explanation: Air is light, but even the strongest person cannot hold their breath for long without exhaling.

A teapot.

Explanation: The word "teapot" begins with "T", ends with "T", and contains tea ("T") inside it.

A towel.

Explanation: A towel absorbs water as you dry yourself, meaning it becomes wetter while drying you off.

An egg.

Explanation: To access what's inside an egg (the yolk and white), you must first break its shell.

A candle.

Explanation: A candle starts tall, but as it burns, it becomes shorter over time.

A cold.

Explanation: You can "catch" a cold, meaning you can become sick, but it's not something you physically throw.

Your age.

Explanation: As you grow older, your age increases, but it never decreases.

A clock.

Explanation: A clock has hands that tell the time, but they don’t perform any other functions, like clapping.

Footsteps.

Explanation: When you walk, every step you take leaves a footprint behind, so the more you walk, the more footprints you leave.

A piano.

Explanation: A piano has keys, but these keys produce music, not unlock anything.

A needle.

Explanation: The "eye" of a needle is the small hole you thread with, but it doesn't serve the purpose of seeing.

A stamp.

Explanation: A stamp is placed on letters or packages that travel across the world, yet the stamp itself remains in place on the item.

A towel.

Explanation: A towel absorbs water when it dries something, thus getting wetter as it performs its job.

5 cents.
Explanation: If the ball costs 5 cents, the bat costs $1.05, which makes the total $1.10.

5 minutes.
Explanation: Each machine takes 5 minutes to make one widget, regardless of how many machines are working.

47 days.
Explanation: Since the number of lily pads doubles every day, the pond would be half-covered the day before it becomes fully covered.

75 miles.
Explanation: The trains will collide after 1 hour (100 miles divided by 50 miles per hour). In that time, the bird will have flown 75 miles.

Right back where he started.
Explanation: He walked in a perfect square, returning to his starting point.