Physics

This chapter covers topics such as Asteroids, Comets, Meteors and Meteorites, Stars and the Star World, Planets of the Sun, etc.

This chapter covers topics such as Human Eye—A Living Lens, Spherical Lenses, Eye Defects, Introduction to Refraction, Formation of Images by Lenses, etc.

This chapter covers topics such as Reflection of Sound and Echo, Hearing of Sound, Amplitude, Frequency and Time Period of Vibration, Sound and Medium, Properties of Sound, The Sound Produced by Different Musical Instruments, and Production of Sound.

This chapter covers topics such as Electric Cell, Liquids Conduct Electricity, Electroplating, Chemical Effects of Electric Current, etc.

This chapter covers topics such as Wind, Steam and Nuclear Energies, Fossil Fuels, Primary Source of Energy, Solar Energy, Hydroelectric and Tidal Energies, etc.

This chapter covers topics such as Factors Affecting Friction, Friction a Necessary Evil, Earthquake—A Natural Phenomenon, Methods of Increasing or Reducing Friction, Force of Friction, Fluid Friction, etc.