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How was the universe created if physics states matter can neither be created nor destroyed? Find out the answer »
Since water molecules are negatively charged on one side and positive on the other, can you freeze a container of water which you place in a magnetic field and create an ice-magnet? Find out the answer »
A ninth grader wants to know what it's like to be a physicist. Here is one physicist's response.
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On Saturday, I accidentally left a full cup of diet soda sitting in my car. It was originally full of ice, which of course melted over the course of a day and a half. When I got into my car on Monday morning, the straw was just over half full of soda, extending about 2" above the full level of soda in the cup. This condition held constant for quite some time, even when the cup was lifted and jiggled/disturbed. Once I had taken a tiny sip, the level of soda in the straw went back down to where I would have expected to find it (at the same level as the soda in the cup). Given that this was a standard lid (with an opening at the top for the straw that is certainly not airtight, nor was the top opening of the straw airtight at all) I could not imagine how the soda in the straw was being pushed or pressured to a higher level than the soda in the cup. The weather over the weekend was cold, but not freezing, averaging in the low 50's. Why did the liquid level in the straw from my soda rise above the liquid in the cup after being left in my car for the weekend? Find out the answer »
If the recent result of the tests of the speed of the neutrino are validated by other research groups what are its implications for the standard model of particle physics as it has been described to date?
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There seems to be a lot of debate about how accurately CERN measured the departure of their neutrinos. Could they not aim them at some other neutrino detector in the world and just use the difference in distance and time from the readings in Italy as this would eliminate the error in not knowing exactly when the neutrinos left CERN?
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When carrying out the double slit experiment using electrons or buckyball molecules, do the particles have to be traveling at near light speed velocities to produce an interference pattern?
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When we talk about an object on an incline, the force of gravity has two components, one vertical and one parallel to the incline, as you know, while the normal force is matched in magnitude by the vertical component of gravity. When we talk about a banked road, however, the normal force becomes the force whose both components are considered, while gravity becomes the force that is matched by the vertical component of normal force. In a way, they almost reverse their roles. Why is that?
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If you shake the sun, how long would it take before it had an effect on the position of the earth?
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Since the earthquake in Japan the country has been having trouble with their nuclear energy plants and possible meltdown. The question is why aren’t they using lead to absorb the radiation?
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Does an ice cube have heat energy (kinetic energy)? If so, does a glass of water with ice have more heat energy than a glass of water without ice?
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If a helicopter hovers in a fixed position for 24 hours will the earth rotate around it?
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I built a sand art box for performing sand art but I have a problem. The sand I use keeps bouncing around on the glass as opposed to being pencil thin. How or what kind of sand can I use to remedy that?
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If an object is sitting on the ground, not moving, is it accelerating towards the earth? I ask because gravity is an acceleration and gravity is always acting on all objects, but acceleration measures the change in speed of an object. So if it is not speeding up, but gravity is acting on it, is it accelerating?
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Can you explain why a penny under a glass beaker of water disappears? If you add some water to top of the penny and return it to under the beaker it is visible.
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What are the scientific reasons for spin or curve on a soccer ball? What forces are affecting this?
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Why is it said that increasing heights of building affect the revolution time of earth?
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Why does a stationary body above the surface of the earth not change its position after some time while the earth is moving? Suppose if we place an object above the surface of the earth, would it be at the same position after some time and why? Find out the answer »
Is it true that pressure exerted by a human foot is more than than exerted by that of an elephant? Find out the answer »
Explain how beautiful sunrises and sunsets are the result of dust in the atmosphere? Find out the answer »
How is the photoelectric effect used to produce a current in a photovoltaic cell? Find out the answer »
Question: I want to ask why water is shaped like a ball when it is in space without gravity? Find out the answer »
If someone was 137 and 5 foot 7 in. how many newtons would it take them to escape the gravity of earth? Find out the answer »
I understand now why the sky is blue, but why are sunsets red and orange? - AB, Oak Ridge, TN Find out the answer »
Is it possible to have an instantaneous zero speed but still have an acceleration? Please give an example. - J Find out the answer »
Would a vertical pipe 50 miles long, one end at or near sea level and the other end in space, suck air into space? It seems as though the vacuum of space should create a flow through the pipe since the pressure at each end is different. - P Find out the answer »
It was my understanding that the velocity of an object falling through air has to do with gravity and wind resistance only. Does the object's velocity have anything to do with its weight or mass? - JVN, Brisbane, Australia Find out the answer »
What happens when you use the tab on an inside rearview mirror to diminish the brightness of the headlights behind you? RC, Vail Colorado Find out the answer »
How does pressure affect humans? Why do our ears pop at high altitudes? — KC, Chino Hills, CA Find out the answer »
How do the machines that concentrate oxygen out of the air work? These machines are used by people with breathing problems - DK, New Orleans, LA Find out the answer »
On earth, two objects of different masses fall at the same rate. However, in space, larger masses exert greater gravitational attraction than smaller masses. This seems inconsistent. What am I confusing? - DD, Miami, FL Find out the answer »
How does MP3 recording compress digital music by factors near 10? I roughly understand zip encoding, but that usually only reduces file sizes by 2 or less. — J, Greenbelt, MD Find out the answer »
What is mass? I thought mass was the same as weight, but my friend pointed out that in orbit you have no weight but you still have mass. So what actually IS mass? — TP, London, UK Find out the answer »
Why is it that when you hear an airplane it sounds like it is coming from somewhere behind where the airplane really is? Is it because light travels faster than sound? - S, TX Find out the answer »
Some lights in my home are controlled by two different switches. How is this possible? - V Find out the answer »
Why is it that when you severely kink an Ethernet cable, you can no longer transmit data on it? That cable contains 4 twisted pairs of copper wires and kinking the cable doesn't break or short out those wires. Why should the kink matter? - DB, Evansville, Indiana Find out the answer »
My brother asked me if there's a difference in weight between an empty and a full hard disk. He was kidding, but it made me wonder if there might be a small difference on the molecular scale. Is there? — RVO, The Hague, The Netherlands Find out the answer »
What are the advantages and disadvantages of convection ovens over standard ovens? – KK, Rochester, NY Find out the answer »
My electric toothbrush charges up by sitting in its base unit. There is no metal-to-metal contact—only plastic-to-plastic. Since the plastic is non-conductive, how does it charge? – RS Find out the answer »
How does the placement of a car's center of gravity affect it? - SM, York Beach, Maine Find out the answer »
Why are the earth and other large celestial objects always spherical? – SP, Mumbai, India Find out the answer »
I've heard that digital encoding on audio CDs represents a pressure wave. But audio has so many components like volume, pitch, and timbre; how can the binary encoding of a pressure wave encompass all these attributes? RY, Madison Wisconsin. Find out the answer »
Why does a steel ball bounced on a steel surface bounce higher than any other ball on the same surface? - JL, California Find out the answer »
Why if you drop a ball from say 2 meters does it bounce higher than a ball dropped from 1 meter? - E Find out the answer »
How do water-bottle rocket work? I know about Newton's third law and everything, but I don't know how it all goes together in a bottle rocket. - Z, Vancouver, WA Find out the answer »
Do bubbles last longer in cold weather or hot weather? Why? — A, Alpharetta, Georgia Find out the answer »
After a tropic thunderstorm, why does it feel so nice to breath? - WM, Kota Baru, Kelantan, Malaysia Find out the answer »
For a science project, I made a parallel circuit and a series circuit. Each is powered by a 6.3-volt battery and has three six-volt lights on it. Why is the series circuit so much dimmer than the parallel circuit? - ML, Woodbridge, CT Find out the answer »
I have a question about a tennis racquet: when I hold the racquet like a frying pan (plane of the head horizontal) and give it one flip, it changes from smooth up to rough up (or vice versa). When I flip it with the plane of the head vertical, nothing peculiar happens. In both cases, I try not to impart any rotation about the long axis. - GF, Shawnee, Kansas Find out the answer »
I can't understand the instruction stated on my tennis racquet about the relation between string tension and string power. It says "higher tension for more control and less power and vice versa". How can it happen? – AT, Hong Kong Find out the answer »
Why does an electric generator slow down when you begin to use the power it is generating? – WV, Waverley, South Africa Find out the answer »
If you coupled a motor to a generator and connected them to the same power source, would the generator be able to recycle wasted power from the motor and thereby reduce costs? — JH, Australia Find out the answer »
Why can a human being sense some accelerations, such as in a car or airplane, but not others, such as free fall? - MDJ, Ozark, MO Find out the answer »
In his book "Understanding Physics," Isaac Asimov writes "As the earth rotates about its axis, the surface of the earth is continually undergoing an acceleration inward toward the center of the earth (just as the moon does in revolving around the earth." Does that mean that the acceleration on the surface (g = 9.8 m/s2) is directly related to the centripetal acceleration of an object traveling in a circle (a = v2/r)? - DW, Raleigh, NC Find out the answer »
How do I explain the difference between the following two situations to my junior high son: (1) The horizontal velocity of a bullet fired horizontally from a gun has no effect on how long the bullet takes to hit the earth, i.e., how long it takes gravity to bring the bullet down to earth. (2) The horizontal velocity of the Space Shuttle orbiting the earth does affect how long it takes for the Space Shuttle to hit the earth. The velocity of the Space Shuttle makes it keep missing the earth in its free fall. – MMH, Ohio Find out the answer »
Why do we see only one side of the moon and the other side is permanently hidden? - KS, Vienna, Austria Find out the answer »
Why does my older farmhouse feel warmer and seemingly easier to heat the colder it gets outside? I live 20 minutes north of Maine, which should give you an idea what kind of winter temperatures we have to endure. - JS, Greenfield, New Brunswick, Canada Find out the answer »
Do you think humans will ever be able to predict the weather? BL, Schenectady, New York Find out the answer »
I'm studying how wind power is used to produce electricity and would like to know how a generator works. - MO, Canandaigua, New York Find out the answer »
As a downhill cyclist, I enjoy riding "drop-offs," i.e. riding off the edge of drops in the ground and landing at the bottom. It seems common sense to me that the faster I go when I hit the edge, the easier the landing. However, some of the physics I have learned in school suggests that my horizontal velocity would not matter, as my vertical velocity would be the same in any case. Is there something I am forgetting? - IE, Oban, Argyll, Scotland Find out the answer »
An electron beam, such as the one found in a TV picture tube, is composed of negatively charged electrons. Why is it that this beam does not rapidly spread out owing to the electric repulsion? I realize that the tube has various focusing magnets and such, but I would think the electronic repulsion would be a serious problem. - JT, Buffalo Grove, IL Find out the answer »
Why does a basketball bounce higher when it has more air in it? - SR, Charlotte, North Carolina Find out the answer »
Why do mylar balloons lose or seem to lose helium when taken outside in the cold and blow back up or seem to blow back up when you take them back in where it is warm? — TS, Alabama Find out the answer »
If a truck full of parrots hits a bump in the road and all the parrots begin flying around inside the truck, does the truck's weight stay the same or not? HJ, Thisted, Denmark Find out the answer »
We're confused about the difference between fluorescent and halogen bulbs. Fluorescent bulbs are classified as hazardous waste because they contain mercury. Do halogen bulbs also contain mercury? - LR and APM, Washington, DC Find out the answer »
What causes the smoke produced when you extinguish a candle flame?— SB, Plymouth, England Find out the answer »
Why is it easy to stay on a bike while moving, but impossible once it stops? - AS, Switzerland Find out the answer »
If you fell into a swimming pool full of Jello, would you be able to swim to the other side? — LM, Charlottesville, VA Find out the answer »
