• Light and Optics

  • Light I
  • Did you know?

    Did you know that scientists and philosophers debated for centuries about whether light traveled in waves or particles? Finally in the 20th century, one of science's "most beautiful experiments" seemed to confirm the wave-like nature of light, until it was further refined some 100 years later.

    Summary

    For centuries, controversy over whether light is made of particles or waves abounded. This module traces the controversy over time, from Isaac Newton's "corpuscle" (particle) theory, which prevailed for centuries, to Thomas Young's groundbreaking double slit experiment, which provided evidence that light traveled in waves.

    • NGSS
    • HS-C4.3, HS-PS4.B1
    Key Concepts
    • A long-running controversy in science, debated by many prominent scientists, was over whether light consists of particles or waves.
    • In the early 1800s, Thomas Young provided clear evidence that showed that light exhibits properties consistent with wave behavior; specifically showing that it exhibits patterns of constructive and destructive interference.
    • Our modern understanding of light has built on the work of Young and others.

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  • Light and Electromagnetism
  • Did you know?

    Did you know that visible light is no different in its form from microwaves, radio waves, or X-rays? Throughout the nineteenth century, scientists dedicated themselves to the study electricity and magnetism. James Clerk Maxwell unified these two ideas in his theory of “electromagnetism” and demonstrated that light was just another form of electromagnetic radiation.

    Summary

    The study of electricity and magnetism were artfully united in John Clerk Maxwell’s theory of electromagnetism. This module explores the experimental connection between electricity and magnetism, beginning with the work of Oersted, Ampere, and Faraday. The module gives an overview of the electromagnetic nature of light and its properties, as predicted by Maxwell’s mathematical model.

    • NGSS
    • HS-C4.3, HS-PS4.B1
    Key Concepts
    • In the mid-1800s, scientists including Andre Ampere and Michael Faraday noted a connection between electricity and magnetism and carried out a series of experiments that showed how they interact.
    • James Clerk Maxwell built on the work of Faraday and developed a single set of equations defining both electricity and magnetism, unifying the concepts into one theory of electromagnetism.
    • We now know that the electromagnetic spectrum is made up of a series of waves of varying wavelength and visible light is just one small portion of this spectrum.

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  • Mechanics

  • Energy
  • Did you know?

    Did you know that when you warm your hands by rubbing them together fast, you are changing energy from one form to another? There are many different forms of energy, any of which can be changed into other forms. This conversion of energy is what makes all of our daily activities possible.

    Summary

    The concept of energy has fascinated scientists and philosophers for thousands of years. This module describes early ideas about energy and traces the development of our modern understanding of energy through the work of Joule and Faraday. Potential and kinetic energy are distinguished, and the six main forms of energy are described. The module highlights energy conversion and discusses how energy is measured.

    • NGSS
    • HS-C5.3, HS-PS3.A1
    Key Concepts
    • Energy is defined as the capacity to perform work.
    • Energy comes in many forms, such as mechanical, chemical, heat, etc. and all are interchangeable to some extent.
    • James Joule was instrumental in establishing the concept of interchangeability of different forms of energy and quantitatively measured those changes in certain systems.

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  • Gravity
  • Did you know?

    Did you know that the same force that makes an apple fall to the ground holds vast galaxies together? Gravity affects our activities every day, and yet it is not well understood by scientists. However, whether it is a small marble dropping from someone's hand or the motion of planets around the sun, the behavior of objects under the influence of gravity can be described mathematically.

    Summary

    Isaac Newton's description of gravity was not the first explanation of this phenomenon, nor was it the last. This module explores how Newton built on the work of early astronomers and how his theory was confirmed and built upon by others. Mathematical equations are presented for (1) the Law of Universal Gravitation, (2) the Gravitational Constant, (3) Earth's mass, and (4) the gravitational attraction between two people.

    • NGSS
    • HS-C3.5, HS-PS2.B1, HS-PS2.B2
    Key Concepts
    • Though the mechanisms of gravitational force are still a mystery, physicists have been able to effectively describe the influence of gravity on objects.
    • Newton’s mathematical model describing gravitational attraction paved the way for other scientists to build toward an understanding of the relationships between mass, acceleration, and the force of attraction.
    • Using the Law of Universal Gravitation, it is possible to predict the behavior of objects under the influence of gravitational force.
    • According to the Inverse Square Law, as the distance between two objects doubles, the force of gravity between those two objects decreases by a factor of four.

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  • Thermodynamics I
  • Did you know?

    Did you know that heat and temperature are not the same thing? If you add heat to ice water, the temperature of the water does not change until the ice has melted. This is the first Law of Thermodynamics at work. In fact anytime heat makes something happen, the laws of thermodynamics apply.

    Summary

    Without heat flow, nothing can move, no chemical reactions can take place, and no machines can run. This module introduces the concepts of heat and thermodynamics. It explains early ideas about heat and how scientists came to understand that heat and work are two different forms of the same thing. The First Law of Thermodynamics is described (simply put, energy cannot be created or destroyed). Other topics include latent heat and the measurement of heat.

    • NGSS
    • HS-C4.2, HS-C5.3, HS-PS3.B2
    Key Concepts
    • Thermodynamics is the study of the relationships between heat, mechanical, chemical and other forms of energy and the effects of these forms of energy on or within a system.
    • Heat is a form of energy that moves from areas of high to low, and it can be converted into work energy.
    • The First Law of Thermodynamics, a variant of the Law of Conservation of Energy, states that within a closed system, energy may change form but cannot be created or destroyed.

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  • Waves and Wave Motion
  • Did you know?

    Did you know that destructive tsunamis and beautiful music have something in common? They are both types of waves. When a stadium crowd does “the wave,” they are demonstrating the physics of wave motion. Similarly, shaking a Slinky from one end creates wave motion. Waves are all around us in many forms and are important to just about every branch of physics.

    Summary

    Waves have been of interest to philosophers and scientists alike for thousands of years. This module introduces the history of wave theory and offers basic explanations of longitudinal and transverse waves. Wave periods are described in terms of amplitude and length. Wave motion and the concepts of wave speed and frequency are also explored.

    • NGSS
    • HS-C1.4, HS-PS4.A1
    Key Concepts
    • The study of waves dates back to the ancient Greeks who observed how the vibrating strings of musical instruments would generate sound.
    • While there are two fundamental types of waves - longitudinal and transverse - waves can take many forms (e.g., light, sound, and physical waves).
    • Waves can be described by their exhibited properties: frequency, speed, amplitude, and wavelength.

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