Neil deGrasse Tyson Explains the Difference Between Mass, Weight, and Density

If you’re trying to get in shape you need to lose weight, right? Neil deGrasse Tyson says wrong. On this StarTalk explainer, Neil and comic co-host Chuck Nice are breaking down the differences between mass, weight, and density.

To start, Neil tells us why when you want to get in shape, you need to lose mass. You’ll learn why a weight-loss book written by a physicist would just be one sentence. We explore the difference between mass and weight and why weight is all about forces.

Then, we move on to density. Find out why heavy cream is lighter than skim milk. We explore how the hull of a ship keeps the ship buoyant. All that, plus, Neil explains why, if you want to lose weight quickly, just head to the Moon and hop on a scale.

About the prints that flank Neil in this video:

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Science meets pop culture on StarTalk! Astrophysicist & Hayden Planetarium director Neil deGrasse Tyson, his comic co-hosts, guest celebrities & scientists discuss astronomy, physics, and everything else about life in the universe. Keep Looking Up!

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0:00 - Introduction
1:07 - How To Lose Weight
1:38 - Mass
3:57 - Weight
5:01 - Density
7:47 - Neil’s Coffeeshop Dispute
9:02 - How To Float
11:15 - Units of Mass, Weight and Density
13:41 - Why Fat Floats
14:24 - Why Ice Floats
14:53 - Closing Notes

[alexkid]

One on momentum, angular momentum, torque etc would also be nice.

[HecJ]

At this point, Chuck is getting a free PhD just by being around Neil 😂

[EdwardHowton]

Mass is an amount of stuff.
Weight is the amount of force exerted by stuff under gravity.
Density is the amount of stuff in a given amount of space.

A bunch of feathers is a mass that weighs 5kg and takes up a huge amount of space because it isn't dense.
A barbell is a mass that weighs 5kg and takes up a small amount of space because it's pretty dense.
"Mass" is hard to quantify without gravity. If you have a six-sided die (d6) made out of _papier maché_ and another one made out of iridium, one will be much heavier, because it's much denser, meaning it has more mass in the same volume as the other one. A box of tissues and a gold brick have about the same volume, but you can pick up the tissues with your bare hands. With no gravity, you can pick up both, but the gold bar will still have more mass, and it will still have the same density.

You can file that under Things Flat Earthers Refuse To Understand.

[talonit]

"YOU JUST GOT SCIENCED"
Neil Degrasse Tyson, 21st century, 2020 (human calendar), Milky way, Planet Earth.

[aquadark]

Just randomly about the ivory soap floating being a feature. It was likely a selling point when showers weren't a thing and you only had people taking baths. So if you let go of the soap you'd rather have it float and be easy to find than try and find a slippery thing at the bottom of some murky water.

[Metalhorse_]

I wish my Science teacher taught me like this, I wouldn't have taken Commerce and Accounts.

[isatousarr]

Listening to the StarTalk podcast always takes me on a nostalgic trip down memory lane, reminding me of my high school science classes. I have fond memories of physics, chemistry, biology, and agricultural science lessons that laid the foundation for understanding concepts like mass, weight, and density. It's fascinating to revisit how mass is the amount of matter in an object, weight is the force of gravity acting on that mass, and density is the mass per unit volume. I’m truly grateful to all my teachers and the school administration for their excellent work in making these subjects so engaging and informative.
I also want to extend a heartfelt thank you to my university lecturers and higher education module leads for their dedication in providing me with deeper insights into the scientific world. Additionally, my work mentors and supervisors have been instrumental in teaching me both research lab work and the theoretical and practical thinking that have been invaluable in my career. Thank you to Neil and Chuck for a job well done on the StarTalk podcast; you guys rock! How do you think our early education in science shapes our understanding of the world today?

[kaloyankolev]

Imagine entering a coffee shop and seeing Neil Degrasse Tyson outsmarting the waiter who lied to him haha. Tremendous.

[GlenHunt]

Gotta say that these videos are more important to me during this time than you could ever know. Thank you for doing you!

[garyb]

Here in Ireland (in the UK too, I think), what you call "heavy cream" in the US is called "double cream". We have "single cream", "whipping cream", and "double cream", which all have differing amounts of fat.

[FlareDarkStormGem]

I have been told that the soap floating was a selling point because at the time people still took baths in lakes and if you dropped your soap it was very difficult to find, whereas if it floats you can see it float and get it very easily
Idk how true that is but I remember being taught that

[kaizerdestiny]

This episode was very interesting. I knew these things, but was never able to explain it to others. Thanks for the lessons! I love you guys.

[Bryanhaproff]

It's 4:20 and time for another Xplainer VIdeo! Never miss an episode. Thank you Chuck for all your hard work at making me Feel More Intelligent than I normally do.

[coffeeshangarworkshop]

I think Chuck gets an additional bonus in any gravitational situation because his humor is so uplifting. :-)

[originaldylanbaxter]

Thanks for the mention fella's. We lumberjacks certainly appreciate the enormous physics/dynamics we unleash during production of our wood cylinders. Big fan!
- Paul Bunyan Guy

[christosbereris]

Neil and Chuck! When I was in grade 9, I my science teacher stated that as gas compressed to liquid and then solid, it's volume diminished...but ice-water was an exception. I asked why it behaved differently and she simply answered: I don't know. It's been bothering me ever since, and I'm now 36 years old. Please please please don't forget to answer this question in either an explainer video or a cosmos queries. Thank you!

[juliedattilo]

Love this explanation, might have a few words in it ;-) that I might hesitate sharing with my 4th graders, love the explanation! Neil is the only one who can explain about astronomy to this elementary science teacher and have her understand!

[pulkitmohta]

The only explainer video where these guys talk about the topics of future explainer videos. They better make those videos soon

[rakshitkumar]

Have a question: difference between neutron star, pulsars and quasars?

[drottningu]

With this episode you have me excited for some cool future explainers!!!