小学校の時、塾で石灰水が二酸化炭素に反応して白く濁るのを確かめる実験で呼気をストローで石灰水に吹き込む実験をやったが・・・【再】
Most people probably remember the elementary school science experiment where they blew into limewater with a straw to detect carbon dioxide in their breath. This content brings back nostalgic memories of that experience, from being amazed by the cloudiness to recalling unexpected mishaps. Online, the experiment sparked various reactions, including fond memories, humorous anecdotes ('Someone actually drank it!'), and new perspectives.
Related Keywords
What is Limewater?
It's a saturated solution of calcium hydroxide in water, which is colorless, transparent, and alkaline. It reacts with carbon dioxide in the air to produce calcium carbonate, causing it to turn cloudy. This property makes it commonly used for detecting carbon dioxide. In elementary school science experiments, it's a familiar chemical often used to confirm carbon dioxide in exhaled breath. It's relatively safe and widely utilized in educational settings.
What is Carbon Dioxide?
It's a compound made of carbon and oxygen, with the chemical formula CO₂. At room temperature, it's a colorless, odorless gas. It exists in trace amounts in Earth's atmosphere, is used by plants for photosynthesis, and is also produced by animal respiration and the combustion of organic matter. Known as a greenhouse gas, it has attracted international attention as a key contributor to the global warming problem. When dissolved in water, it forms carbonic acid, which makes the familiar limewater cloudy in elementary school science experiments.
What is Exhaled Breath?
It refers to the gas expelled from the lungs by living organisms during respiration. Compared to inhaled air, it has a lower concentration of oxygen and a higher concentration of carbon dioxide and water vapor. For humans, while inhaled air has about 21% oxygen, exhaled breath has about 16%; and while inhaled CO₂ is about 0.04%, exhaled CO₂ is about 4%. In experiments involving blowing into limewater, the carbon dioxide contained in this exhaled breath is used to observe the reaction.
What is the Straw Experiment?
It's a common science experiment, often performed in elementary school, to detect carbon dioxide in exhaled breath. A straw is inserted into limewater in a test tube or similar container, and one's breath (exhalation) is slowly blown into it to observe the limewater turning cloudy. This allows for a visual understanding that carbon dioxide is expelled through our breathing. Because it's easy to conduct, it has become a fundamental experiment for learning about the mechanisms of biological respiration.