How is physics knowledge used in everyday life?

[Orodruin]

I feel that my knowledge of physics let's me adapt better to new situations, in particular when trying out a new sport or activity. It is one thing to learn how to do an activity from an instructor, but that is helped along significantly if you can understand the underlying mechanisms. Would I have needed to know physics to learn how to scuba dive? Probably not, but it certainly helped. I will never forget my course in Nitrox diving (diving with a different mixture of nitrogen and oxygen than the atmospheric one). The students were me, my father, my sister, and my brother-in-law. I am a theoretical physicist and they are all medical doctors and at some point I almost felt sorry for the poor diving instructor who had to "teach" us about the physical and physiological effects of different gas mixtures.

Another use of physics knowledge is avoiding overly pedantic physicists nitpicking on internet forums ...

- A simple acknowledgment of momentum increasing exponentially with speed could have kept her out of the ditch in the first place.

Momentum increases linearly with speed, unless you go at relativistic velocities where it increases faster than exponentially.

- McDonald's might have something to say about how much latent heat is in a hot cup of coffee.

Nothing contains latent heat (or any type of heat). Heat in general is energy that is thermally transferred between two systems and latent heat is the heat released to (or absorbed from) the environment without temperature change during a first order phase transition. What you are implicitly referring to here are the heat conduction and heat capacity properties of hot coffee.

 

[Rive]

How is physics knowledge used in everyday life?

Well, I think the answer is more or less the same for science in general, not just for physics. People are just fine with the surface, and there is no need for 'real' knowledge anymore.

As I see our civilization is advanced through creating (working) operating instructions: science was/is a successful tool for this. But this success also means that most people will never met with science: they will met only with the instructions. This makes things easy - but also makes science to something distant//mystic//difficult//boring for the most.

 

[hmmm27]

Another use of physics knowledge is avoiding overly pedantic physicists nitpicking on internet forums ...

More than fair enough. I'll take you up on the perceived back-pedant opportunity, of course - conductivity seems of rather negligible import compared to heat-capacity in the McDonald's coffee incident.

 

[Orodruin]

More than fair enough. I'll take you up on the perceived back-pedant opportunity, of course - conductivity seems of rather negligible import compared to heat-capacity in the McDonald's coffee incident.

If heat conductivity was negligible you would not burn yourself. It would mean the stored internal energy (given by the heat capacity) would have no way to transfer to the skin in the form of heat.

 

[hmmm27]

If heat conductivity was negligible you would not burn yourself. It would mean the stored internal energy (given by the heat capacity) would have no way to transfer to the skin in the form of heat.

One could (will) argue that thermal conductivity is applied as a macro property, and that the shape of the spill, ie: a meniscus thick or less, minimizes its relevance.

 

[Orodruin]

One could (will) argue that thermal conductivity is applied as a macro property, and that the shape of the spill, ie: a meniscus thick or less, minimizes its relevance.

That still does not make it irrelevant. It still needs to be above some reasonable threshold to equilibrate quickly enough to produce a burn. Of course, that threshold is minimised by a larger contact surface and the fact that both body and coffee are mostly water makes it likely that this condition is satisfied. But it is still not irrelevant to mention it.

 

[hmmm27]

That still does not make it irrelevant. It still needs to be above some reasonable threshold to equilibrate quickly enough to produce a burn. Of course, that threshold is minimised by a larger contact surface and the fact that both body and coffee are mostly water makes it likely that this condition is satisfied. But it is still not irrelevant to mention it.

I think I'm going to pull the ripcord here, and mention that - while I see your point, completely - turbulence of a spill is going to constantly put the newest(ie: hottest) liquid directly onto the contact area.

 

[gleem]

Without delving into the profiles of the endorsers of the usefulness in physics in your everyday life I would bet that most here are physicists or had a strong physics background. As a potential student thinking about taking a physics course for its purported usefulness in everyday life wouldn't you put more credence in the endorsements of non physicists?

 

[nrqed]

Another use of physics knowledge is avoiding overly pedantic physicists nitpicking on internet forums ...

.

This reminds me of an argument I hd with someone on this forum who was adamant that time is exactly the same as space because the two are combined in the metric.. :-)

 

[nrqed]

We all know the question: why do I need to know this? I have been thinking recently about how to add relevance to my curriculum. What I am struggling to come to grips with is how knowing physics, the topics typically taught in a high school intro course, can be useful in everyday life. I am not looking for everyday examples of physics concepts. I mean real actual examples of using Newton’s laws or momentum in real life purposefully. For example, understanding ratios from math is applied purposefully to compare grocery store prices.

Can you think of a time when you actually used your physics knowledge in everyday life?

Thanks,
Bill

People use physics intuitively all the time, and they do much more often than using chemistry, say, and that at a very young age.. One interesting example is the non trivial physics involved when a child use his/her center of gravity to transfer potential energy to kinetic energy in order to start moving on a swing without touching the ground.

Another example is race car pilots who use the fact that in order to go as fast as possible on a curve, one has to maximize the radius of curvature (to minimize the centripetal acceleration. v^2/R), so before getting to the curve, one has to go on the opposite side of the road, and the one has to "hug" the curve and then head to the opposite side of the road when exiting the curve. I am pretty sure they do not know the physics explanation but they all do that instinctively.

But I think you are probably asking examples where people use their knowledge of physics they have learned in school in a conscious way to solve some problem in everyday life, and the answer is clearly "almost never". People do not use any knowledge from their studies in chemistry, or biology either. And people almost never need to use their knowledge of mathematics either, except for maybe adding or multiplying, and even that they usually do with a calculator.I read a great sci-fi short story once, I am pretty sure it was by Asimov. In it, a person from the future was brought to the present day, but just for a very short time. Of course people ask the visitor from the future things like "will cancer be cured?" and the person answers that cancer was cured. They ask how!? The person canonly say "well, when someone is diagnosed with cancer, the doctor gives us some pill and make us sit in a machine and we are cured". Which is of course the situation today as well, people use technology based on advanced science without knowing the principles involved.

 

[Orodruin]

This reminds me of an argument I hd with someone on this forum who was adamant that time is exactly the same as space because the two are combined in the metric.. :-)

I don’t think this is an argument that I would use. I would say that it is natural to use a system of units where time and length have the same physical dimension since they are both just (non-angular) coordinates on the same manifold relating to the length of curves in that manifold and it makes no sense to introduce an arbitrary conversion factor (apart from convenience for everyday at will show up essentially everywhere to obstruct the actual physics.

 

[marthasimons2]

I don't know if this example is exciting enough to demonstrate the laws of physics in our daily life, but it still is worth mentioning. When you want to open a door, you just use the handle that is situated on the other side of the door's hinge. It would be really difficult to open the door if the handle was situated somewhere in the middle, for example. What is used here is the rule of turning forces. Your goal is to create a large moment around a pivot. This idea can be used in various physical activities in real life. When you know the right way of applying your force, it becomes easier to reach your goal.

 

[pinball1970]

I am not a physicist so this should count. Charging up glow in the dark applications at work I used D65+UV in the light box to get quickest results. Other options being Tungsten, TL84, UV on its own or D65 on its own.

 

[symbolipoint]

Piano (acoustic) and guitar (acoustic), depending on what you know and how much you know.
vibrating strings, and tone-woods.
Why? Waves and wave interference.

Also, have you seen a chladni pattern?

 

[RPinPA]

I grew up in a snowy, icy place. I have a peculiar step I use on ice which my wife calls my "ice walk". I almost never fall down or slip on ice because of it, despite the fact that most of the time I am wearing unsuitable footwear (sneakers).

It came from direct contemplation of the physics. I realized that we normally walk by relying on friction. You push on the ground and expect static friction to cause a force moving you forward. Remove the friction and your foot just slides backward, throwing you off balance.

Better: try as much as possible not to do that backward push. Lift the feet and put them down vertically. Obviously there has to be some forward force as you need to move horizontally, but you are deliberately trying to minimize it. If you do it right, you'll be able to get across a lot of slippery patches that are defeating other people.

I also find myself thinking about the physics constantly around the house, with little fix-it things. How many nails, placed where, would give this thing the right structural strength. How do I stabilize this structure? (A single diagonal brace turns an unstable square structure into a stable one). How can I open this jar? (When I realized that it was the vacuum that created the friction of the jar lid, the answer was simple: pry the lid up just a bit and let the air in). What's the quickest way to get 6" of snow and ice off my windshield? (Ice melts at 32 F/0 C. The first thing you do is open the car and start the heater and then wait a minute. It only has to get the window to 0 C to make your life a lot easier).

There are literally hundreds of examples like that. I think about the physics all the time.

 

[CWatters]

It's a fine line between consciously or unconsciously using physics knowledge...

When you buy a phone you check or compare the battery capacity with other models.
When you buy a light bulb you choose how bright it is.
When you buy a car you check it's fuel consumption figures.
When you buy a duvet you look at the TOG value.
If you replace windows in your house you care about insulation and U-Values.
When you go to the beach you might estimate when the tide will come back in.

 

[Frigus]

I think This video has perfect answer(at least for me) for this question.