Lesson 1: Physics and Other Sciences

Video Lesson:

Lesson Objective:

Dear learner,

At the end of this section, you will be able to

Explain the relationship of physics with chemistry, biology, geology and astronomy.

Brainstorming Questions:

• List as many other sciences or specializations as possible in which the word physics appears in their names.
• How is knowledge of physics used or applied in these sciences or specializations?

Key Terms and Concepts

Physics and other Sciences

• Science is systemic knowledge of the physical or material world gained through observations and experimentation.
• Science is a collection of different scientific fields, or disciplines.
• Scientific disciplines do not have fixed borders.
• Physics is a science that deals with matter, energy and their interactions.
• We can find different concepts of physics in many of the modern sciences.

1. Physics and chemistry

• Both physics and chemistry deals about matter and energy. However, physics looks at this question on a much smaller scale.
• Physics concerns the movement of physical objects in time, while chemistry concerns the transformation of physical matter from one type to another.
• Chemists and physics share such knowledge of physics as:
  • Thermodynamics
  • atomic physics
  • nuclear physics
  • matter and energy
  • Chemical bonding
• The boundary between physics and chemistry is not clear.
• Chemists use thermodynamics concepts in many activities like reaction mechanism to calculate the energy involved the reaction and to determine the reaction route and the final product.
• Chemists also use advanced instrument like ultraviolet spectrometer, Infrared spectrometer, nuclear resonance magnetic spectrometer, X-ray diffraction, scanning electron microscope, energy dispersive X-ray and other instruments to study composition, structure, properties, behavior and the changes they undergo during a reaction with other substances of minute entities like elements, atoms, molecules and ions. The working principles of these instruments are based on one or more concepts of physics.
• Spectroscopy is the study of the interaction between matter and electromagnetic radiation as a function of the wavelength or frequency of the radiation.
• Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation.
• Most of what we know about the structure of atoms and molecules come from spectroscopic study. In simpler terms, spectroscopy is the precise study of color as generalized from visible light to all bands of the electromagnetic spectrum.
• The spectroscopic techniques are developed by collaborative work of physicists and chemists.
• In general, the study of matter and electricity in physics is fundamental towards the understanding of concepts in chemistry, such as atomic structure, molecular structure, X-ray diffractions, radioactivity, periodic properties of elements, nature of valency, chemical bonds in molecules, crystal structure of solids and others. This shows that chemistry is rooted in atomic and molecular physics.

2. Physics and Biology

• The laws of physics are important to explain:
  • the mechanics of muscles and body movements,
  • flow of body fluid, blood and air,
  • hearing and audio properties of the ears,
  • vision optics,
  • heat and energy,
  • message transmission.
• Newtonian mechanics tells a biologist about:
  • How different animals and their body parts move.
  • Muscle movements and physical behavior of bones, lungs and the heart.
  • Equilibrium of the body

• Physics of fluid flow tells a biologist about:
  • The circulation of blood in multicellular organism.
  • Movement of soft-body animals like worms.
• Physics of sound wave tells a biologist about:
  • Mechanism of sound creation and transmission

• Physics of electricity and biology / Optical Physics and biology
  • The nervous system of animals and the control of muscle movement is controlled by electrical interactions.
  • Neurons are message transmitting networks in our body with the brain as the center of the network.
  • The message in our body is transmitted as electric pulse by the neurons.
  • Our electrical condition measured externally can give our health condition.
  • Shark uses electric signal to locate their prey and to communicate with other sharks.
  • Electric eel can generate along its skin electric pulses up to 500 V.
  • Though electric signal is always there in our body, a current larger than about 10 mA damages our body by contracting muscles.
  • Light is important for animals to see objects and for photosynthesis for plants.
  • Optical physics supports biology by providing optical instruments, like microscopes, which are important to study biological properties.

3. Physics and Astronomy

• Astronomers study objects far from them (Earth).
• Astrophysics is the study of the physics of heavenly objects, called astronomical objects, in the sky like the solar system and its constituents, the properties, birth, life and death of stars, interstellar gas and dust, galaxies and clusters of galaxies, and finally the study of the Universe as a whole.
• Astronomers try to study astronomical objects by studying the component of electromagnetic radiation from these objects.
• Astronomers use Newton ‘s law of gravitation
  • to describe the motion of astronomical objects around an orbit.
  • Mass of astronomical objects
• Astronomers use light to:
  • Measure distance between astronomical objects.
  • study the properties of astronomical objects from the properties of the light they emit.
  • The energy emitted by the astronomical objects.
  • Temperature of the astronomical objects.
• Astronomers use different telescope to detect the type of light coming from the astronomical objects.
• A telescope is an optical instrument using lenses, curved mirrors, or a combination of both to observe distant objects, or various devices used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation.
• Telescopes may be classified by the wavelengths of light they detect:
  • X-ray telescopes, using shorter wavelengths than ultraviolet light
  • Ultraviolet telescopes, using shorter wavelengths than visible light
  • Optical telescopes, using visible light
  • Infrared telescopes, using longer wavelengths than visible light
  • Submillimeter telescopes, using microwave wavelengths that are longer than those of infrared light
  • Radio telescopes that use even longer wavelengths
• Astronomers used light year as an astronomical distance measuring unit. A light year is the distance the light travel in one year.
• Atomic physics plays a key role in astrophysics as light from astronomical objects is emitted through atomic transitions.

4. Relation of physics with Geology

• Earth Science deals with all aspects of the Earth including molten lava, icy mountain peaks, steep valleys and towering waterfalls, the atmosphere, planet ‘s core.
• Geology is the study of the solid matter that makes up Earth, like rocks, minerals, mountains, and canyons.
• Common geological processes and the analytical techniques use basic physics concepts like force, optics, atomic structure, electromagnetic radiation, heat and heat flow, electricity and magnetism, stress and strain, sea waves, acoustics and fluids and fluid flow.