On Density

Density is one of those topics that science classes frequently include – especially in the physical sciences. Yes, it’s the ratio of mass to volume – or as I like to think – how much stuff is contained in a given space.

Like any formula as D=M/V, given any two variables, it’s possible to calculate the unknown. Density is more than just working formulas – after all – it is an important concept to understand – but most teachers focus on density as it’s covered in a textbook or as their designated drills to pass a state-mandated test.

To me, it’s the application of density into our everyday world that gives the topic relevance. For instance, wood is more than just wood. Product information for a new fireplace or wood-burning stove may include information about softwood and hardwood.

Given 2 logs of the same size, the hardwood log (oak) will have more mass (think of it as heavier when you pick it up) than the softwood log (pine). There’s more wood substance packed into the given space as the same-sized log of softwood. Bottom line being that the hardwood log will burn longer and release more heat.

When density is applied to populations in biology, Hong Kong is very dense – just like hardwoods – well, more like ebony, one of the most dense hardwoods.

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Which is heavier, five pounds (kilos) or one pound (kilo) of water? That’s a no brainer – the oil is heavier, so will five pounds (kilos) float on one pound (kilo) of water? Sure it will because oil is less dense than water (Note: we could include a discussion about solubility, but will stick to density). Yep – that’s why we shake that bottle of Italian dressing before we use it.

Hot air doesn’t rise – (it never has and it never will) – but it is displaced upward by the colder air that is also more dense. (Here’s a past post that addresses that misconception). The same idea can be applied to any fluid (liquid and gases), so now density helps explain currents in the atmosphere and in bodies of water. https://afrankangle.wordpress.com/2012/08/08/on-hot-air/

You may remember the story of Archimedes (Greek mathematician, physicist, and inventor) whom the king called upon to determine if the crown was real gold or not. Legend has it that the explanation came to Archimedes while in a bathtub – “Eureka!” Of course, his points about density and displacement eventually led to how boats and ships float.

While at a party, you want a soda – which is found in a large metal tub. All the ice has melted, but the cold water is still keeping the cans cold. You notice some of the cans are floating and others lie on the bottom. The sign says Diet Soda and Regular Soda. You want a Diet soda, and density is telling you which one to pick.

Readers are wondering why I wrote this post – or at least what sparked the idea. After all, long-time readers here know I have reasons for what I do. I like Chex cereals – and earlier this year I bought a box of each of my favorites in the Chex family. (The written number represent ounces and grams.) Personally, I like the more dense one better – and it’s more filling – which should not be a surprise.

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47 thoughts on “On Density

  1. So your fondness for Wheat Chex inspired this post, eh Frank? I used to eat Wheat Chex, too, but when I switched my diet to organic and/or locally grown foodstuffs, I switched to Kashi’s Organic Promise Autumn Wheat “naturally sweetened whole wheat biscuits”. It’s rather good with fresh blueberries. The box’s net weight is 16.3 ounces / 462 grams. It’s a dense cereal.

    Liked by 1 person

  2. Your mind does work in interesting ways, Frank! When I got to the comparisons of Chex cereals I had to laugh! Science over breakfast! 🙂 It’s not unusual to hear me talking about population density, which is becoming more and more alarming to me.


    • Debra,
      Cheers to you for getting the chuckle part of my style! Actually, this post has been in my head for some time, so I had to do it. In terms of population density, oh yes … you live it much more than most of us. Can you imagine Hong Kong?


  3. Thanks for the science lesson, Frank. I had no idea where you were going to go with this.
    Hope you enjoyed your Chex. 🙂
    I used to buy all sorts of dry cereals when the girls were home, but now I usually stick to oatmeal (regular, not quick).


  4. Personally, I prefer a small bowl of nuked frozen blueberries topped with just enough Captain Crunch to sweeten them. The Crunch is no doubt concocted arcanely of stuff that’s bad, but some chemical genius found a way to make it resist the milk better than any other I’ve found. Texture is an important part of enjoyment. Crunch is less dense than blueberries, but not much. Yum.

    Liked by 1 person

    • Jim,
      No doubt, science was at work in the creation of Captain Crunch. My wife also enjoys nuked frozen blueberries in the morning …. but she puts them over Greek yogurt and tops the concoction with granola cereal for the crunch. … but your version has to be more crunchy.


      • Gotta have those numbers for that money.
        Sadly, in the beginning progress monitoring and data offer change: you determine where each child is in mastery of a concept, then teach or reteach to individual level making steady progress. But that depended on time to analyze and skill to interpret and flexible curriculum with enough additional matterials/time to support the sequence….what wasn’t anticipated was the collection of data that was only ignored and the march through the textbooks never detoured – only marched on as course mandates said “there simply wasn’t time for anything else”. So that was all a waste of everyone’s time. Then of course peopel tried to “fix” it by having more and more progress monitoring which morphed into endless annoying testing schedules (not geared to checking student’s progress inobstrusively along the learning path with a real purpose). And “experts” (many famous ones/well known resaerchers have no children/ever taught school) over looked the fact that kids are not widgets – and that testing days are a snapshot of that one moment on one day – with hundreds of variables that affect a kid’s score on that day…including lack of sleep, hunger, most often lack of interest in performing on a “stupid test” once past 3rd grade or so. (few researchers want to acknowledge the last one…data researchers often are pure number people – not engaging their social genes)
        Win-win for testing and edu material companies, though. (Big lobbying groups)
        It’s all very sad the wonder of learning and the amazing discovery of all sorts of stuff is systematically being stripped out of kids.
        You’ve seen it, too. Sigh.
        Dense world in many aspects

        Liked by 2 people

  5. Very interesting post, and also your reason for choosing the subject of density, Frank. 🙂 I remember the Eureka moment, in fact it’s about the only think I do remember from my school science and math classes. Nowadays, I’m happy to find that I can buy shampoos and conditioners which promise to improve the density of my hair. 😀

    Liked by 1 person

  6. Science is everywhere and this was a great way of demonstrating the point! I used to do the same with politics–it’s really about power (who has it, who doesn’t, how it’s used). Power having it or wanting it) is a ubiquitous element of social life–not just the stuff of elected officials. Science is not just the stuff of people in white lab coats!

    Liked by 1 person

  7. My current client is a airplane manufacturer, though I work specifically for the service side of the house. One of their services, is paint repair or repainting when the plane is sold to a new owner. Some private jets have fabulous paint jobs, I learned something new recently. When designing those fabulous paint jobs, it requires engineering participation due to the density of paint. The added weight impacts how those jets fly and thus the safety.



      • It is both actually if you talk to Quality or Engineers. If a plane was designed for X and you as the new owner decide to put a new paint job on it changing the total weight significantly, you change the operation of the plane. If that plane wasn’t designed for that weight, especially in the smaller jets (commercial versus business class) you can be putting stress on engines and other mechanical operations.

        There is a vast difference between a 747 and a Learjet.


    • LB,
      You are on the right track … Let’s say both Pepsi (thus dark) … but one diet & one regular. The diet floats because the artificial sweeteners are so sweet, much less of it is used instead of sugar.


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