Physics 201 Curiosity Questions, Fall 2007:
Collected from students before taking intro physics. This is a wonderful colection of uninhibited natural world questions. Many were addressed in class.



What would happen to the earth if the sun suddenly ceased to exist? Would it instantly fling off into space instantly? Wouldn't that mean gravity traveled faster than the speed of light?

Can ice really be made into a viable bullet, is something other than water frozen to make it work, or is it just Hollywood make-believe?

How does the F-117A Nighthawk deflect incoming radar, and why are these angles (of the body plating) optimal for being stealthy against radar?

Is  levitation truly possible?  Also, as a physicist, have you encountered  
anything related to physics that cannot be explained, or can be  
considered as something of the supernatural?  If most of the world can  
be explained through the eyes of a mathematician, how much of it  
cannot?

What are some physics applications in the human body?

How can I relate physics to the human  
body and its movement?  I am an athletic training major and want to  
know some sample problems that relate to the human body and its  
actions or movements, instead of problems about the speed or velocity  
of a ball or a car.

Which is stronger : triangles or arches?

Anyway, my question was spurred by the rumors and kind of "urban legends" surrounding living near a power substation. I realize that there has been substantial research done on the subject and no deleterious health effects have been proven. However, since we currently have one in our backyard, I was wondering if it was possible that electromagnetic forces could somehow otherwise affect our bodies ( i.e., thoughts/dreams/etc?) and the mechanism by which it could do that.

I know that sun dials work by the change of the sun's position during  
the day, but in higher lattitudes, where winter days are shorter, are  
sundials still used? If so do they have to take into acount the amount  
of light/dark? Or do they plug in the date and angle of shadow into an  
equation to get the time?

Why when your walking to class in the rain do you get less wet then if  
you are running or biking to class? (Ignoring the splash factor on a  
bike). It seems like the faster you go the more wet you get. I believe  
it was proved on Myth busters but does (and if yes, what kind of)  
physics backs this up?

Lets say an anvil and apple where dropped from the same exact height.  
Which of the two would reach the ground faster?

So my little brother once asked me if you fired a bullet straight up  
would it fall back into the barrell and my mom and I had a  
disagreement on why not, or under what circumstances it might happen.

If you toss  
a ball straight up in the air 2 meters and catch it at the exact same  
spot you threw it from, at 1/2 meter above that spot is the ball going  
faster on the way or on the way down?

Can you predict where a leaf will land based on the wind, the shape of the leaf, and the height it falls from, or are all those measurements too variable?  Are there other variables that would also matter?  

Why is it when you are snorkeling, or swimming and you do a breast  
stroke with your arms and then begin kicking it seems to shoot you  
forward?

I was wondering how baseball stitching affects its spin, and if it
would be possible to throw a whole different variety of pitches if the
balls were stitched differently.  I know that the stitching and spin
on the ball is how movement in pitches is achieved but why and how
much is spin and how much is the stitching.

How does a boomerang work?  Why does it come back when you throw it?

My question is why does water stay in a bucket if you rotate
it over your head?

How is it that the simple act of swinging your legs back and forth  
can keep you  swinging when you're on a swing?

My question is how is a bumble bee able to fly with such a large body and small wings?

my question is about the physics surrounding the world of winter sports athletes and the extreme jumps they are able to live through.  I have a general knowledge of why these jumps are possible but i would like to know the actual forces that are coming together to make it possible.  Just for your information as far as i know the current world records for a cliff drop (a vertical fall) is approximately 250 vertical feet and the longest distance covered horizontally as approximately 190 feet. the cliff drop rider had to be dug out of the hole he made on impact (he was reported to be about 6 feet deep in the snow and suffered only a split lip from biting it on impact) and the distance jumper rode away from the jump cleanly with out ever leaving his feet!  

What are some physics applications in the human body?
 
how does a curveball in baseball work? Don't one of the physics laws  
state that an object cannot change motion in midair unless another  
force hits it?

why do some things float in water and some things not?

why do densities effect weight.

why does the world rotate (at all) on an axis?  and what does the  
rotation affect on earth?

What causes the earth to continually rotate?

Why do the stars seem to stay in the same place if the world is moving as well as the sun/moon?

what keeps planets in orbit?

I know that sun dials work by the change of the sun's position during  
the day, but in higher lattitudes, where winter days are shorter, are  
sundials still used? If so do they have to take into acount the amount  
of light/dark? Or do they plug in the date and angle of shadow into an  
equation to get the time?

Which is more of a phenomena; lunar eclipses or solar eclipses?
Why is the moon year shorter than the sun’s rotation around the earth?

Why does the full moon have such a strong impact the the tides?
I know the text book answer, "gravity," but break it down for me. Is  
it really as simple as the moon being closest to that area at that  
time and thus looking full and pulling more on the water in that area  
of the ocean? I feel like there must be more to it, what else is going  
on?

How does the pull of the moon control the tides?  How can one predict the high and low tides?

What is the distance between the earths core and the surface?

I read in the textbook that physics plays a role in the medical  
profession in aiding in the obtainment of images of the interior of  
the human body. I am curious as to how it does, because I do not  
clearly see the connection.

How is it that the gravitational pull is always to the centre of the planet? Or is this  
only because that is all we see?

I have heard that the moon controls the waves or tides in the ocean. Is this true and if so how does it work?

The moon, earth, and sun all have a gravitational pull, but what causes this? How exactly does it suck objects towards them?


What keeps a satellite in orbit around the Earth?

Why do planets rotate and why can we not feel it?

What are the effects of physics on a roller coaster??

Why does a pendulum swing for so long?

Why is it that the time duration between each swing on a swing-set  
(The duration of going back and going forward) is the same no matter  
the height of the swing? (eg Bob starts his swinging and is swinging  
really high. Carl starts swinging but swings half as high as Bob. The  
duration for Bob to swing forward when he is back is the same duration  
for Carl to swing forward when is back and vice versa.)


When a tree falls in the forest and there is nobody around to hear it, does the tree still make a noise when it falls? 

I would love to know more about how timbre is created.  What  
determines different timbres?  I play the clarinet and music revolves  
around different timbres so it would be great to learn more about it.


On a piano, as the notes get lower, the strings in the piano get thicker and shorter. Why does the string size and thickness cause the sound to change?

How is it that my son and I can talk to eachother with 2 tin cans and  
some string and hear eachother clearly? When you are driving a car...why is the sound pitch of an approaching  
car high as it approaches you and low after is passes you?

How is it possible to measure the speed of sound? Speed of light?

How do soundwaves affect the stability of structures (i.e. bridges,  
buildings, spiderwebs, etc

I heard somewhere that certain sound frequencies can breakdown specific materials.  If this is true, would it just have to be one blast of  
that frequency or would there have to be a prolonged exposure to it for say a bridge to collapse because of it? Also, if sound waves can break apart materials, can they help strengthen them or protect them?

How do radio waves penetrate walls (how does a radio receive signals within a house)?

Why is it easier to climb up than climb down?

If a weight is swung is the challenge of that weight greater or less then if it simply lifted?

How and why do earthquakes occur?

It's my understanding that the potential energy of an object increases
as it's lifted from the floor for example to a desk. (maybe this is
wrong) If this increases the objects potential energy, what happens if
the object is lifted beyond the gravitational field of the planet?

How do people jump?"

If a bullet from a rifle is fired into  
a body of water how far will it actually descend? 


Why does time differ from a moving object and an object standing still?

What is time made of? (particles? waves? a line with a forward arrow? or is it just a concept used to describe a dimension?)

What is faster than the speed of light?


I am curious why liquid assumes a tear  drop shape in the air?

How is it that when you turn a bucket upside down in water it is hard to bring it up out of the water even though it doesn't have any water in it?-And how high can you lift it?

I studied Poiseuille's law in one of my classes, unfortunately  
everybody had taken physics so they understood the concept.
I find hemodynamics facinating, so I guess my question is more of a  
request:
I'd love to know more about Poiseuille's Law and if there is ever a  
situation in which Poiseuille's Law DOES NOT work? (i.e. elevation,  
etc.)

One physics observation or question that I thought up upon pondering the universe was how we use blood pressure to determine cardiac health. I am a pre-pharmacy major so this is of some interest to my field.

In the average human body, how much force does our body have to exert on our veins to return the blood from our feet to our heart?  I know that there is not enough force exerted by the heart to return the blood all the way from our extremeties so the veins have valves that prevent backflow and our muscles squeezing the veins during movement help bring the blood back.  I have always been curious as to how much work needs to be done be the muscles to bring that blood back.

How does the blood in the small vessels in the limbs of your body get back to your heart?

How does an airplane stay in the air?

How does a Boeing 737 take off from the ground in terms of physics?

How can the increase of entropy be reversed?

What is fire? Like what makes the flame a flame?

Why is fire so hot amd orange?

I'm not particularly talented at coming up with questions, but I heard my dad asking how water and other liquids can't pass through our skin even though it's all just a bunch of atoms. I am going take that as the question.

How do radio waves penetrate walls (how does a radio receive signals within a house)?


Why is the sunset turn the sky a pink and orange color when its setting?

What makes the sky blue? Does it have to do with the wavelengths of  
light that are reflected or refracted?

Why do microwaves boil water?

What is faster than the speed of light?

How does glow-in-the-dark objects retain light and actually glow?

how does a double rainbow form?

How are telescopes made so that it can magnify the stars to such a degree?

How is physics involved in eyesight?

Why does light bend when it goes through glass?

How exactly do mirrors work?

what makes fiber optics work?

Light as a Particle or wave?

I've noticed that wave crests get closer together as they roll up a beach; that they change direction as they go around a rock, or enter narrow gates. Why does this happen?


How is it that we can determine which chemicals make up a specific compound based off NMR?" Along the same lines, NMR is the same as an MRI but how do we get an image from the same technology?

In the vastness of everything, protons, neutrons, and electrons are still the basic building blocks.  How is it that these simple, tiny structures can compose and set in motion something that is so complex through an explanation of physics?

Is the proton really stable, or does it eventually decay?

How do so many types of waves (radio, television, etc.) travel through the air and our bodies without doing any noticeable harm to us?


How is it that the universe can be said to be infinite? Does this mean that the universe is continuously growing and creating new galaxies, planets, etc? or Has it already been created to point that is so vast an massive that we just say that it is inifinte because we cannot actually prove that it is actually infinite?

Does the universe have an end?  Or is it infinite? Or does it loop?

How is light affected by gravity if it does not have mass? 

I was wondering if there was any way that a machine can be created to travel through time, space, and/or universe?

How can physics help me to understand what dark energy is all about?

What is a black hole? And how can our ordered universe house such a anomoly?

I know that the first three dimensions are spatial and the fourth is generally considered a time dimension but I was curious to know what the fifth dimension was and if it actually existed.

Is it possible to reach speeds faster than light in space [assuming Einstein's theory that space is curved and other theories that space and time are connected] and how would that affect the perception of time for the passengers?

Given the rotation of the rotation of the earth around the sun, the sun around the galaxy, and the galaxy through space, how fast are we moving while just sitting here?

What is the maximum velocity of a falling star?

Is underground liquid water a possibility on Mars? 

Can you explain the process behind shooting stars?

I would like to learn the process of how a star works.

Is there a way that we (people) could set up a habitat on the moon, and if so, why haven't we done it?     

How do you measure the distance between Earth and the Sun?

Is there any scientific basis to support the saying that every atom in our body was once part of a star?


Why are there different eye colors?

Do species really exist or are they simply a useful convention to help us understand nature?

Why do fruits and vegetables change colors as they ripen?

Why do leaves change color in the fall?

Why does the sun lighten our hair, but darken our skin?

Why does ice cream make you thirsty?

Why do people cry when they are sad?

What is stoping humans from using our brains and  bodys to their fullest potential? Such as not using our full strength or using all of our brain.

How do different animals sense different color hues, for example some can sense IR or UV which is out of what we consider "visable" light.  How do they incorporate that into their "mental image" of the world?

So here's my question for you... How is it that hot water freezes  
faster than cold water? I've heard this is true! 

I am the type  
of person that gets the anoying hic-ups very frequently when I dink  
soda pop. And I have tried everythng to get rid of them. One way that  
I found worked was to drink water with a spoon in the glass while  
hanging upside down. How does it work? I heard (sources untold) that  
hic-ups are the bodies way of expressing that they are not getting  
enough oxygen to the muscles. So why would the water spoon trick work?

Could the problem of global warming be solved by moving the earth  
farther from the sun? If so, what other problems would this possibly  
trigger?