Have you ever wondered why we feel cold? It’s a chilly -1 degree Celsius, and while it feels cold, technically, “cold” isn’t something you can touch or feel. It’s more about what’s missing rather than what’s there.
Everything around us, including air, ice, and even our bodies, is made up of tiny particles called atoms. These atoms are always moving, even if things feel solid. Temperature measures how fast these atoms are moving, which is known as their kinetic energy. Temperatures can range from super hot, like the lead ions in the Large Hadron Collider at five and a half trillion kelvin, to absolute zero, where all atomic motion stops.
When it gets cold, we don’t feel the temperature itself; we feel the energy leaving our bodies. This happens in three ways: conduction (heat transfer between solid objects), convection (heat transfer through fluids like air or water), and radiation (heat transfer through electromagnetic waves). Feeling cold is just energy moving from our bodies to the colder surroundings, making our atoms move less.
Which do you think is hotter: a boiling tea kettle or an iceberg? While the kettle has a higher temperature, the iceberg actually holds more thermal energy. If both were placed in a pool of ultra-cold liquid nitrogen, the iceberg would warm the pool more than the kettle.
Space is often thought of as empty, but it’s not completely void. If you were floating in deep space, you’d freeze quickly, even though the few atoms out there can be extremely hot, up to a million kelvin. Temperature depends on the average kinetic energy of atoms, not their number. A thermometer wouldn’t work well in space because there’s not enough matter to measure.
On a cold day, wind can make us feel even colder. You might think moving air should be warmer, but it’s not. The atoms in our skin and the air are already moving fast. When wind brings in new, colder air, it causes us to lose more heat, making us feel colder. This is why blowing on hot tea cools it down and why a tile floor feels colder than carpet.
Heat transfer explains why you lose heat faster in cold water than in snow and why touching a hot pan can burn you while you can briefly put your hand in a hot oven. It’s also why you should never touch your tongue to a frozen flagpole!
We feel cold because of the second law of thermodynamics. The universe is always trying to balance things out, spreading energy evenly. Life, however, is about holding onto energy and using it in interesting ways.
Isn’t that fascinating? Keep exploring and stay curious!
Conduct a simple experiment to understand how temperature relates to the movement of atoms. Fill two bowls with water: one with hot water and one with cold water. Add a drop of food coloring to each and observe how quickly the color spreads. Discuss how this relates to the kinetic energy of the water molecules.
In groups, role-play the three types of heat transfer: conduction, convection, and radiation. Use props like a metal spoon, a fan, and a flashlight to demonstrate each type. Explain how each method transfers heat and why it makes us feel cold.
Engage in a debate about which holds more thermal energy: a boiling kettle or an iceberg. Research and present arguments for both sides, considering temperature and total energy content. Conclude with a discussion on how this relates to real-world scenarios.
Simulate the effect of wind chill by using a fan and a thermometer. Measure the temperature of a wet sponge with and without the fan blowing on it. Discuss how wind increases heat loss and why it makes us feel colder.
Research and create a presentation on temperature in space. Include information on why space can be both extremely hot and cold, and why traditional thermometers don’t work well there. Share your findings with the class.
Sure! Here’s a sanitized version of the transcript:
—
[MUSIC] It is currently -1 degree Celsius, it is raining, and I am feeling quite cold. Technically speaking, there’s no such thing as “cold” as a substance; you can’t literally feel cold. When you touch something frigid, there’s nothing called “cold” in there. It’s what isn’t there that really matters.
[MUSIC] Matter makes up air, ice, human beings, and everything else. It’s composed of atoms, and no matter how solid something feels, those atoms are constantly in motion. Temperature is a measure of that motion, or the kinetic energy of the atoms. The scale of temperature ranges from lead ions in the Large Hadron Collider at five and a half trillion kelvin to absolute zero, where all atomic motion stops.
When the temperature drops, we don’t actually feel the temperature itself; we feel the flow of energy. We feel heat leaving our bodies. There are three ways that energy is transferred: conduction, which is the transfer of heat between solid objects; convection, which uses the movement of fluids; and radiation, which relies on electromagnetic waves. The sensation of being cold is really just energy moving from one temperature to another, causing our matter to jiggle less and the surrounding matter to jiggle more.
Just like when a rubber ball loses energy every time it bounces and eventually comes to a stop, the universe takes energy from us and keeps it for itself. It’s quite greedy!
So, which is hotter: a boiling tea kettle or an iceberg? [TICKING CLOCK] The kettle, obviously. If you put a thermometer in both, the boiling water will register a higher temperature. However, the iceberg contains more thermal energy. If both were dropped into a swimming pool of ultra-cold liquid nitrogen, the iceberg would warm the pool more than the tea kettle.
Once we leave Earth, things get even more complicated. Space is often thought of as a vacuum, but it isn’t completely empty. If we collected a cubic meter of deep space, say, between two galaxies, we might only count a hundred atoms. If you were floating out there, you’d freeze almost instantly, yet those atoms could be at temperatures up to a million kelvin. Temperature doesn’t depend on the number of atoms, just their average kinetic energy. If we put a thermometer out there, it wouldn’t read anything due to the lack of matter.
If temperature is all about kinetic energy, why does wind on a cold day make us feel even colder? Shouldn’t the moving air be hotter? On a small scale, the atoms and molecules in the air and in our skin are already moving quickly, so adding a little wind doesn’t change that much. My atoms are moving at normal body temperature, while the atoms in the cold air are moving slower. When my atoms bump into the slower air atoms, I lose heat and feel cold. Wind brings in fresh, less energetic air, causing me to lose even more heat.
This is also why blowing on a cup of tea cools it down. Heat transfer explains why a tile floor feels colder than carpet; the tile is denser, with more atoms ready to absorb warmth. It’s also why you’ll lose heat faster in cold water than in snow, and why touching a hot pan can burn you while you can briefly put your hand in a hot oven.
And it’s why you should never touch your tongue to a frozen flagpole, even if challenged. We feel cold because of the second law of thermodynamics. The universe is on a long mission to even everything out, increasing entropy and lowering energy until everything reaches equilibrium. Life, on the other hand, is about holding onto energy and using it in interesting ways.
That’s fascinating. Stay curious!
—
Let me know if you need any further modifications!
Temperature – The measure of how hot or cold something is, usually measured in degrees Celsius or Fahrenheit. – The temperature of the water increased as it was heated on the stove.
Atoms – The basic units of matter, consisting of a nucleus surrounded by electrons. – Everything around us, including the air we breathe, is made up of tiny atoms.
Energy – The ability to do work or cause change, which can exist in various forms such as kinetic, potential, thermal, and more. – The energy from the sun is essential for plants to perform photosynthesis.
Heat – A form of energy that is transferred between objects with different temperatures, moving from the hotter object to the cooler one. – When you touch a hot stove, heat is transferred to your hand, causing it to feel warm.
Cold – The absence of heat or a lower temperature, often making objects feel chilly to the touch. – The cold wind made it necessary to wear a jacket outside.
Conduction – The process by which heat or electricity is directly transmitted through a substance when there is a difference of temperature or electrical potential. – Metal is a good conductor of heat, which is why pots and pans are often made of metal.
Convection – The transfer of heat through a fluid (liquid or gas) caused by molecular motion. – In a pot of boiling water, convection currents help distribute the heat evenly.
Radiation – The transfer of energy through space by electromagnetic waves, such as light or heat from the sun. – The warmth you feel from the sun on a sunny day is due to radiation.
Kinetic – Relating to or resulting from motion; kinetic energy is the energy an object possesses due to its motion. – A rolling ball has kinetic energy because it is moving.
Universe – All of space and everything in it, including stars, planets, galaxies, and all forms of matter and energy. – Scientists study the universe to understand how it began and how it works.
