odour
Definition
Odour is a physical property of a substance that is detected by the sense of smell. Odours are caused by volatile organic compounds (VOCs), which are small molecules that can easily evaporate into the air.
VOCs are released by a variety of substances, including plants, animals, foods, and chemicals. When VOCs bind to receptors in the nose, they send a signal to the brain, which is interpreted as an odour.
The human nose can detect a wide range of odours, but some odours are more easily detected than others. For example, we can easily detect the odour of a rose, but we may not be able to detect the odour of a skunk unless it is very close.
The intensity of an odour can also vary depending on the concentration of VOCs in the air. For example, the odour of a rose will be stronger if there are more rose petals in the air.
Odours can also be subjective, meaning that what one person considers to be a pleasant odour, another person may consider to be unpleasant. For example, some people enjoy the smell of coffee, while others find it unpleasant.
How can the word be used?
The sense of smell is important for detecting danger, finding food, and identifying people and objects.
Different forms of the word
Noun: A distinctive smell, typically pleasant.
Verb: To emit an odour.
Adjective: Having a strong or unpleasant odour.
Etymology
The word "odour" comes from the Old French word "odour," which is also the source of the Dutch word "geur" and the German word "Geruch." The Old French word "odour" is thought to be derived from the Latin word "odor," which means "smell.".
The word "odour" was first used in English in the 14th century. It was used to refer to a distinctive smell, typically pleasant.
Question
What can create an odour?
AQA Science Exam Question and Answer
Question:
Describe the role of olfaction in perceiving odours and explain how the brain processes these olfactory signals.
Answer:
Olfaction, the sense of smell, plays a crucial role in perceiving odours and interacting with our environment. When we encounter different substances, molecules from these substances are released into the air as volatile compounds. These molecules enter our nasal passages during inhalation and bind to olfactory receptors located in the olfactory epithelium, a specialised tissue in the nasal cavity.
The olfactory receptors are highly specific and can detect a wide range of odour molecules. Each receptor responds to a particular set of molecules, creating a unique pattern of activation. These signals are then transmitted to the olfactory bulb, which is part of the brain responsible for processing smells.
From the olfactory bulb, the signals are relayed to various brain regions, including the olfactory cortex, which is responsible for identifying and recognising specific odours. Interestingly, olfactory signals also connect with areas of the brain associated with memory and emotion, which is why certain scents can trigger strong emotional responses or vivid memories.
The brain's processing of olfactory signals is complex and involves pattern recognition, comparison with stored odour memories, and integration with emotional responses. This intricate process allows us to perceive and interpret a vast array of odours, enriching our experience of the world around us.