Physics

A:

The exact composition of light has eluded physicists for years, but the predominant theory is that light is comprised of a kind of energy called electromagnetic radiation. This energy behaves like a wave and a particle in different situations. Scientists believe electromagnetic radiation is composed of bundles of energy called photons.

See Full Answer
Filed Under:
  • Does light always travel at light speed?

    Q: Does light always travel at light speed?

    A: Light typically travels at 186,000 miles per second, but scientists have found a way to slow it down to 38 miles per hour. A team at the Rowland Institute for Science has found a new state of matter to help slow light down. Sodium atoms were cooled almost to absolute zero, which is 459.67 degrees Fahrenheit below zero. That’s lowest temperature theoretically possible. They then shot a laser through the extremely cold sodium atoms, which acted like “optical molasses” to slow down the beam of light.
    See Full Answer
    Filed Under:
  • What are examples of noncontact forces?

    Q: What are examples of noncontact forces?

    A: Electricity, gravity and magnetism are all examples of non contact forces. A force is anything that can cause a physical change in an object.
    See Full Answer
    Filed Under:
  • What are the parts and functions of a theodolite?

    Q: What are the parts and functions of a theodolite?

    A: A thedolite is an instrument used to measure horizontal and vertical distances using lenses and lines. They include several components, such as a telescope, a leveling mechanism, a tripod and a compass. Theodolites are used for surveying and construction to obtain precise readings of landforms so construction projects remain level and plumb with the ground.
    See Full Answer
    Filed Under:
  • How does gravity affect humans?

    Q: How does gravity affect humans?

    A: Humans evolved with gravity, and gravity affects human physiology and general health. Studies show that weightlessness has a number of negative health effects. Finding ways to mitigate these dangers is essential for long-distance space travel.
    See Full Answer
    Filed Under:
  • What were the contributions of Archimedes to the field of physics?

    Q: What were the contributions of Archimedes to the field of physics?

    A: The first-century inventor and scientist Archimedes is remembered by physicists as the originator of the principles of mechanics, buoyancy, the lever and the pulley, according to Famousscientists.org. Perhaps his best-known contribution to physics is his discovery of the principle of displacement, which states that objects displace a volume of water equal to their own weight.
    See Full Answer
    Filed Under:
  • What are the Laws of Attraction and Repulsion?

    Q: What are the Laws of Attraction and Repulsion?

    A: The Law of Attraction is the belief that a person's thoughts attract specific things, people and situations into his life. The Law of Repulsion is the belief that the more a person thinks about what he does not want, the more he attracts what he does want. According to SelfGrowth.com, both beliefs support the idea that what a person thinks about, negative or positive, can manifest into reality.
    See Full Answer
    Filed Under:
  • Why does rubbing your hands together make them warmer?

    Q: Why does rubbing your hands together make them warmer?

    A: Friction causes the hands to warm up when rubbed together. The greater the amount of friction between two objects is, the more heat is generated.
    See Full Answer
    Filed Under:
  • Why does a bouncy ball bounce so high?

    Q: Why does a bouncy ball bounce so high?

    A: Bouncy balls bounce high because the material of the ball is extremely elastic and can convert the kinetic energy from the fall into potential energy and back again with very little loss in momentum. Bouncy balls are used in many physics classrooms because they aptly demonstrate conservation of momentum through a highly elastic collision.
    See Full Answer
    Filed Under:
  • How are mass and weight related to each other?

    Q: How are mass and weight related to each other?

    A: Mass and weight are closely related because mass affects the weight of an object experiencing the effects of gravity. Weight is the measure of the force of gravity on an object's mass, while mass is the measure of how much matter there is in an object.
    See Full Answer
    Filed Under:
  • How does a fulcrum work?

    Q: How does a fulcrum work?

    A: A fulcrum is the fixed support or pivot point for a lever, which is a simple machine used to overcome resistance. The lever is a stiff rod or bar, and the location of the fulcrum determines the class of the lever. Levers are useful to increase force, increase speed or change direction of a force, according to HowStuffWorks.
    See Full Answer
    Filed Under:
  • What is the purpose of a windmill?

    Q: What is the purpose of a windmill?

    A: A windmill uses wind power to create rotational energy for the use in mills, pumps and presses. In the Netherlands, where windmills became important for local economies, they were used to make boards, paint, oil, paper and bread.
    See Full Answer
    Filed Under:
  • What are some good lab experiments that explain centripetal force?

    Q: What are some good lab experiments that explain centripetal force?

    A: One good experiment that explains centripetal force is the spinning penny. A penny is put inside a balloon, and the balloon is filled with air. Then, the balloon is swirled around until the penny rolls around inside of the balloon. The penny continues to spin even after the swirling stops.
    See Full Answer
    Filed Under:
  • What is the formula for tension in physics?

    Q: What is the formula for tension in physics?

    A: In physics, the tension on a suspended object said to be equal to the weight of the object plus or minus the mass of the object times the acceleration acting on it. In other words, this is the weight of the object plus or minus the force on it, depending on the direction in which the force is acting.
    See Full Answer
    Filed Under:
  • What is the difference between kinetic and potential energy?

    Q: What is the difference between kinetic and potential energy?

    A: Kinetic energy is contained in a moving object, while potential energy exists in a stored form. Potential energy can be changed into kinetic energy. Potential energy is ready for release, while kinetic energy is already doing work. The property of a body determines the type of energy it contains.
    See Full Answer
    Filed Under:
  • What is the difference between an atomic bomb and a nuclear bomb?

    Q: What is the difference between an atomic bomb and a nuclear bomb?

    A: Although both atomic and nuclear bombs derive their immense power from reactions that take place in the nucleus of the atom, they do so in different ways. As the terms are most commonly used, an atomic bomb derives its energy from fission, or splitting atoms, while a nuclear device, or "H-bomb," is driven by fusion.
    See Full Answer
    Filed Under:
  • What are the pros and cons of Maglev technology?

    Q: What are the pros and cons of Maglev technology?

    A: In comparison with existing modes, Maglev technology is a better way of moving people and freight because it has a long service life and is faster, safer, cheaper and less congested. Maglev also saves energy because of its high efficiency and lack of pollution emission. However, Maglev guideways cost more than the conventional railway tracks. The lack of existing infrastructure is also a disadvantage.
    See Full Answer
    Filed Under:
  • How can I determine the positive and negative sides of a magnet?

    Q: How can I determine the positive and negative sides of a magnet?

    A: The north and south poles, often called the negative and positive sides, of a magnet are determined by using the directional properties of magnets. The north pole of the magnet is attracted to Earth's geographical north pole, and the south pole is attracted to Earth's geographical south pole.
    See Full Answer
    Filed Under:
  • Why doesn't sound travel through a vacuum?

    Q: Why doesn't sound travel through a vacuum?

    A: Sound does not travel through a vacuum because molecules of matter are required for sound to exist, and vacuums do not have any matter. The vibrations and movements of small particles of matter are what create sound and allow it to be heard. In a vacuum without any matter, such as space, it is impossible for sound to travel.
    See Full Answer
    Filed Under:
  • What are radio waves used for?

    Q: What are radio waves used for?

    A: Radio waves are used to receive and transmit signals between two objects. These waves help to transfer signals from broadcasting stations to televisions and radios, and they are also used to transmit signals for cellular phones.
    See Full Answer
    Filed Under:
  • What are the characteristics of sound waves?

    Q: What are the characteristics of sound waves?

    A: The most basic characteristics of a sound wave are pitch, loudness and tone. A sound wave's frequency is experienced as the wave's pitch. The amplitude determines loudness or volume. The tone of a sound wave can be recognized by the regularity of its vibration.
    See Full Answer
    Filed Under:
  • What is the Doppler effect?

    Q: What is the Doppler effect?

    A: The Doppler effect is an observed shift in the frequency of a wave as the source of the emission moves relative to the observer. As a sound- or light-emitting object moves closer to an observer, the pitch of the emissions rises. As the object recedes, the pitch falls.
    See Full Answer
    Filed Under: