StarTalk Radio – "Things You Thought You Knew – Force, Heat, & Speed"

Podcast: StarTalk Radio
Host: Neil deGrasse Tyson
Co-Hosts: Chuck Nice, Kevin
Original Air Date: November 18, 2025

Episode Overview

In this lively and comedic science explainer episode, Neil deGrasse Tyson leads co-hosts Chuck Nice and Kevin through three pairs of everyday concepts that people commonly confuse: Force vs. Pressure, Heat vs. Temperature, and Speed vs. Acceleration. Using relatable analogies, witty banter, and pop culture references, Tyson clarifies the true meanings behind these physics terms and points out the misconceptions encoded in our language and culture.

Key Discussion Points & Insights

1. Force vs. Pressure (02:14 – 18:28)

Definitions and Physics Basics

• Force: The push or pull exerted on an object, calculated as mass multiplied by acceleration (Newton’s Second Law).
• Pressure: Force distributed across an area; mathematically, pressure = force ÷ area.

Everyday Examples & Thought Experiments

• The Gym Spotter (04:00 – 07:20)

  • Tyson explains why a gym spotter doesn't need to be super strong: when the upward force and the weight are balanced, even a small additional force can make a difference.
  • "If all forces are balanced, then any force will move it, no matter how small." – Neil deGrasse Tyson (05:16)

• The Role of Net Forces (07:20 – 09:00)

  • Objects move (accelerate) only when there's an imbalance of forces.
  • Constant speed (e.g., cruises at 60 mph) indicates total forces (engine, friction, air resistance) are balanced.

• Pressure in Action (10:00 – 14:18)

  • Walking on Ice & Snowshoes: Spread your weight (force) over a larger area (big shoes or snowshoes) to lessen pressure and avoid breaking through.
    • "If pressure is force divided by area and that area gets smaller and smaller, the pressure gets higher, and you punch through that ice and you die." – Neil deGrasse Tyson (11:10)
    • "You need clown shoes. Get the biggest ass shoes you can find." – Neil deGrasse Tyson (11:29)
  • Sharp vs. Dull Knives: Sharp blades have a smaller area, so the same force means higher pressure, making cutting easier.

• Tornadoes and Exploding Houses (14:18 – 16:41)

  • Tornados cause destruction from pressure differences, not directly from wind force. Even a tiny pressure differential (e.g., 0.1 lb/in²) across a house’s surface area builds to thousands of pounds of total force.
    • "That is pressure at its most deadly." – Neil deGrasse Tyson (16:34)

• Bonus – How Bombs Work (16:52 – 17:41)

  • Bombs and explosions are about rapid expansions, generating sudden pressure differences that destroy structures.

Memorable Moments

• Chuck’s comedic interjections on dating pressure vs. physics pressure (09:04).
• Pop culture quip: "It’s why a tornado can explode your house... That pressure builds on top of £1,000 of pressure." (15:53)

2. Heat vs. Temperature (22:44 – 33:26)

Definitions

• Temperature: The average kinetic energy (motion) of the molecules in a substance.
• Heat: The sum of the kinetic energies—total energy—in all the molecules.

Core Distinctions

• A single molecule does not have a 'temperature' (24:15). Temperature is a property of the whole ensemble.
  • "Temperature is a macroscopic thing... The average kinetic energy of its vibrating molecules." – Neil deGrasse Tyson (23:01)
• Fast-moving molecules at the 'tail' of the distribution can evaporate even if the overall temperature is low (25:33).

Everyday Examples

• Hot Coffee vs. The Ocean (27:39 – 29:34)

  • "Your cup of coffee... at 210 degrees Fahrenheit, is hotter than the ocean, but the ocean has more heat." (27:39)
  • The vast number of molecules in the ocean means it contains far more total energy, despite its lower temperature.
  • "That’s why your coffee cup is not gonna start a hurricane... the ocean can start a hurricane." – Neil deGrasse Tyson (28:11)

• Climate Change & Oceans (28:57 – 30:40)

  • Small average increases in ocean temperature represent colossal amounts of added heat, with significant climate implications.
  • "The ocean wins every time. It’s this tremendous heat reservoir." – Neil deGrasse Tyson (29:34)

• How Air Conditioners Work (30:42 – 32:49)

  • Air conditioners and heat pumps don’t 'create cold'; they move heat from inside to outside (or vice versa in winter).
    • "There is heat inside of your room... There is a pump that takes that heat, removes it from your air and sticks it outside." – Neil deGrasse Tyson (31:36)
    • Heat can be pumped from even 'cold' air, as long as it’s above absolute zero.

Memorable Quotes

• "Heat is the sum of all the kinetic energies of all the vibrating molecules." – Neil deGrasse Tyson (27:22)
• "Next time you're sipping a cup of coffee, looking out at the ocean... just know that ocean has more heat than this hot, scalding cup of coffee." – Chuck Nice (33:11)

3. Speed vs. Acceleration (36:38 – 48:38)

Definitions & Physics Basics

• Speed: How fast you’re moving—does not specify direction.
• Acceleration: How quickly your speed or direction changes.

Breaking Down the Pop Culture Myth

• Top Gun's “I feel the need for speed!” (37:07)
  • Tyson pokes fun at the iconic movie line, explaining that the thrill pilots feel is not from speed, but acceleration—changes in speed or direction.
    • "Right now... Earth's rotation is carrying us due east at 800 miles an hour. Are you saying I feel the need for speed and this is great? No." – Neil deGrasse Tyson (37:55)
    • "What we think of as motion sickness is not motion sickness. It’s acceleration sickness." – Neil deGrasse Tyson (38:25)
  • The sensation of movement, thrill, or “head snap” is created by acceleration, not constant speed.
    • "When you are moving at constant speed, your body has no idea you’re moving at any speed at all." – Neil deGrasse Tyson (39:14)

Head-Turning Moments: Acceleration in Driving & Flight

• Car ads list both top speed and “0 to 60 mph” times because acceleration is what people actually feel and desire (41:51).
• Electric cars like Tesla are famous for their rapid acceleration; this is what creates the thrilling “head snap” (43:09).
  • "Now that's why everybody loves Tesla... because... very high acceleration." – Neil deGrasse Tyson (43:10)

Going Deeper – The Jerk (44:08 – 45:36)

• “Jerk” is the rate of change of acceleration—this is what causes the most physical distress or damage, as in the sudden snap of a car crash.
  • "If you have a rate of change of acceleration, that has a term in physics, it's called the jerk." – Neil deGrasse Tyson (44:13)
  • "The jerk is what actually does sort of musculoskeletal damage in an accident." – Neil deGrasse Tyson (45:13)
• The old joke: “It’s not the fall that kills you, it’s the sudden stop.” Or, as Chuck puts it:
  • "So what you're basically saying is, jumping out of a 20 story window doesn't kill you... it's the ground that does." – Chuck Nice (45:42)
  • "If there were no ground..." – Neil deGrasse Tyson (45:58)

Why Sports Cars & Motorcycles Feel Exciting

• Rigid suspension in sports cars lets you “feel the road” (46:47).
• It’s the constant banking, jerking, and sudden changes—not simply going fast—that excite enthusiasts.

Notable Quotes & Memorable Moments

• “You get my skinny ass to prevent you from dying...” – Neil deGrasse Tyson jokes about spotting at the gym. (05:39)
• "You need clown shoes. Get the biggest ass shoes you can find." – Neil deGrasse Tyson on pressure and walking on ice. (11:29)
• “That’s more than the Kool Aid man actually exerts through a wall to say, ‘oh, yeah!’” – Chuck Nice, on tornado pressure. (15:57)
• “A single particle has no temperature.” – Neil deGrasse Tyson, busting temperature myths. (24:15)
• “Your coffee cup is hotter than the ocean, but the ocean has more heat.” – Neil deGrasse Tyson. (27:39)
• “What we think of as motion sickness is not motion sickness. It’s acceleration sickness.” (38:25)
• "If you have a rate of change of acceleration, that [is] called the jerk." – Neil deGrasse Tyson. (44:13)
• Chuck’s summative advice: “Please take Neil's word for everything he just said. Let's not try the brick wall experiment for ourselves, okay?” (48:17)

Timestamps of Important Segments

• [02:14] – Force vs. Pressure: physics definitions, net forces, gym spotting, and pressure in real life.
• [14:18] – Pressure and structural destruction: tornadoes and bombs.
• [22:44] – Heat vs. Temperature: molecules, energy, coffee vs ocean, climate.
• [30:42] – How air conditioners work: heat transfer, pumps.
• [36:38] – Speed vs. Acceleration: Top Gun, driving, why 'acceleration' is what thrills us, the “jerk”.
• [46:47] – Why sports cars feel more exciting: suspension, “feeling the road”.
• [47:10] – Motorcycle wheelies and the need for acceleration.

Summary

This episode is a rapid-fire, humor-laced tour through some of the most basic, but most persistently misunderstood, physics concepts in everyday life. Neil deGrasse Tyson and his co-hosts illuminate the crucial distinctions between force and pressure, heat and temperature, and speed and acceleration, helping listeners “feel” and truly understand their significance. They use playful banter and vivid analogies—from tornadoes to Teslas to clown shoes—to make these abstract ideas tangible and memorable. If you’ve ever conflated these terms, this episode will have you laughing—and learning—in equal measure.

Listen to this episode of StarTalk Radio for the full experience. As always, keep looking up!