"How do we hear sounds" Various sounds PPT courseware 3

"How do we hear sounds" Various sounds PPT courseware 3

I am the best

I can listen carefully to the teacher's explanations and classmates' speeches. ( )

I can speak boldly and express my opinions. ( )

I can actively participate in group discussions. ( )

I can ensure order in the classroom. ( )

1. How is sound produced?

Sound is produced by vibrations of objects.

2. How does sound spread?

Sound spreads around through gases, solids, and liquids.

What is noise?

Tell me about your understanding of noise.

Noise is noise. It is a type of sound that causes people to be irritated or whose volume is too strong and endangers human health. Usually refers to those unpleasant, annoying sounds. Noise pollution mainly comes from transportation, vehicle horns, industrial noise, construction, social noise such as concert halls, loudspeakers, morning markets and people talking loudly. Noise can damage hearing; noise can induce a variety of diseases and affect the human nervous system, leading to cardiovascular system diseases and digestive system disorders; noise interferes with people's normal life and work, affects sleep, and causes fatigue.

Noise prevention and control

Attenuate the sound at the object. Even if you use sound-absorbing materials, try to reduce the vibration of the object as much as possible. For example: modify a noisy machine or replace it with a low-noise machine, and add a muffler to the exhaust pipe of the internal combustion engine.

Attenuation during propagation means finding ways to disperse and absorb the incoming noise. For example: adding obstacles during the linear propagation of noise.

Attenuation at the Human Ear: We cannot fundamentally reduce some noise sources, so we have to find ways to solve them ourselves. In order to be able to work, study and rest normally, when noise is unavoidable, you can wear ear protectors, such as earmuffs, earplugs or a small ball of cotton inserted into the ear hole.

Hearing protection common sense

When washing your hair and swimming, avoid sewage entering the ears, which may cause ear inflammation.

When a foreign object enters the ear canal, do not dig it out yourself to avoid damaging the eardrum. Seek medical attention as soon as possible.

Avoid listening to earphone radios or tape recorders for long periods of time, and the volume should be adjusted to moderate or below.

In noisy environments, cover your ears with your hands or wear ear protection.

Only take medications under the guidance of a doctor, as overdose of some medications may cause tinnitus or hearing loss.

When you notice ear discomfort, such as pain or pus discharge, you should seek medical advice as soon as possible.

Expansion exercises

Put a few beans inside a plastic bottle to make a sound-making device. Through our study in this lesson, think about how to make the sounds we hear softer?

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"How Do We Hear Sounds" Various Sounds PPT Courseware 2:

"How Do We Hear Sounds" Various Sounds PPT Courseware 2 Review Questions: 1. How are sounds produced? Sound is produced by the vibration of objects. 2. How does sound spread to distant places? Sound travels through media. 3. The media that propagate sound include...

"How do we hear sounds" various sound PPT courseware:

"How We Hear Sounds" Various sound PPT courseware 1. The structure of the human ear The basic process of how people perceive sound The vibration of the tympanic membrane of sound from the outside spreads through the ossicles and other tissues The auditory nerve transmits signals The brain produces an introduction to common sense of hearing :just..