Solutions of Sound from SCIENCE For Class 8

This topic tells us what a sound is. Sound is a sense that helps us learn and communicate. Sounds can be of different kinds, soft, loud, melodious, etc. We also learn that all sounds are produced similarly.

The topic explains the production of sound. It tells us sound is produced by the vibration in a body. Students can try the activity to notice whether the sound is produced or not. There are different ways in which sound can be produced.

This topic describes the propagation of sound, which means the mode of travel of sound from start to end. It also tells how does sound moves and in what kind of mediums. It also defines refraction, compression, and amplitude.

This topic says that sound travels through a medium. Sound can travel through the air as well as liquids and solids. It includes two activities to understand the topic practically.

This topic explains that sound travels in all directions with the help of an example of the bell. It also elucidates the difference between sound waves and light. Light cannot reach every corner but, sound can.

In this topic, the velocity of sound through different mediums is recorded. The velocity of sound differs in different mediums. It is different in the air than in the liquid or the solid. Also, activity is given to experiment on.

This topic focuses on amplitude. Through the example of a pendulum, the amplitude is made easier to understand. Amplitude is the maximum distance travelled by a moving body from one point to another.

This topic gives us the definition of the time period, with the help of the example of a pendulum or a stopwatch. The time period can be defined as the time taken by a pendulum to complete one oscillation.

The topic defines frequency and mentions its unit. Activity and questions are also provided in this topic to learn more about frequency. Frequency can be defined as the number of oscillations per second.

The topic highlights the characteristics of sound. The sound is mostly based on its loudness and pitch. It also gives a table of some sounds and their decibel values. It discusses the factors that influence the pitch of the sound.

This topic differentiates between audible and inaudible sounds. It also discusses the sound frequencies that humans can hear or dogs and horses can hear. It also teaches about ultrasonic and its uses in medical science, industry, oceanography, etc.

The topic discusses the comparison between noise and music. Pleasant sounds are music; irritating sounds are noises. It also tells how music is created. It briefs on stringed, percussion and wind instruments.

This topic explains how animals and human beings produce sound. It discusses with the aid of an example that the animals have vocal cords. Whereas, in humans, a voice box is present, which consists of vocal cords.

This topic describes the structure of the human ear through which we hear. A detailed and labelled picture of an ear is given. It illustrates the internal parts of an ear. It also explains how the human ear functions.

In this topic, we will learn about unwanted sound and how it affects our hearing. It also discusses noise pollution, sources of noise pollution, its effect on our lives, and how we can control noise pollution.