WHAT IS SOUND? ď ˝
Sound is a form of energy that is transmitted by pressure variation that the human ear can detect. Sound can also travel through other media, such as water or steel. Frequency and intensity are the two features of sound
 Noise is any annoying, disturbing or unwanted sound, that disturbs people or makes it difficult to hear wanted sounds. Depending on the quantity of dB it can hurt in different ways
THE MEASUREMENT OF THE SOUND PRESSURE DOESN'T HAVE A LINEAR EQUIVALENCE RELATION.IT IS A LOGARITHMIC FUNCTION
EFFECTS OF NOISE ON HEALTH
The decibel (dB) table compares some common sounds and shows how they rank in potential harm to hearing. 70 dB is the point at which noise begins to harm hearing. To the ear, each 10 dB increase seems twice as loud.
Sound Levels and Human Response Common sounds
Noise Level [dB]
Effect
Rocket launching pad (no ear protection)
180
Irreversible hearing loss
Carrier deck jet operation (25 m). Thunderclap Jet takeoff (60 m)
140 130 120
Painfully loud Maximum vocal effort
Rock concert
110
Extremely loud
Firecrackers Heavy truck (15 m). City traffic
100 90
Very loud Very annoying Hearing damage (8h)
Alarm clock (0,7 m). Hair dryer
80
Annoying
Noisy restaurant. Business office Conversational speech Light auto traffic (30 m) Living-room, bedroom. Quiet office Library. Soft whisper (5 m) Broadcasting studio
70 60 50 40 30 20 10 0
Telephone use difficult Intrusive Quiet Very quiet Just audible Hearing begins
Cardio-respiratory disfunction Variations in the endocrine system Irritate people Reduce working efficiency Disturb people Hearing loss
Place
Time
Decibels(dB)
Hall
Entry time (8:20)
72
Corridor
Between lesson
78-82
Normal Class
Maths lesson (11:35)
74
Normal Class
English lesson (14:00)
80
Playground
Break (11:15)
90-95
Library
Break(11:15)
68
Normal Class
Break(11:15)
65
Hall
Departure time
95
ď ˝
We can observe that in some moments of the day there is too much noise (78-79 dB), so it can be harmful. That happens because students are in corridors speaking loudly. Nevertheless, in other places there is more silence, maybe because some steps have already been taken. (Example: library)
When it’s yellow or green: Nothing will happen. When it’s red: Students must lower their voice
Awareness posters:
•Through a competition students make a poster to raise awareness of the importance of keeping silence • The winner will get between 50€ and 70€ for school supplies, books…