The Celsius temperature scale is used all over the world today, but not many people know how it came to be. This article will take you through the history of the Celsius scale, the role of Anders Celsius, and how temperature measurement has evolved over time.
Anders Celsius was a Swedish astronomer who is often thought to have created the Celsius temperature scale. However, he didn’t actually use the scale as we know it today. In 1741, while teaching at Uppsala University, Celsius made a thermometer with a scale that marked the freezing and boiling points of water in a way that might surprise you: he set zero degrees at the boiling point and one hundred degrees at the freezing point. This upside-down scale was influenced by the Delisle scale, which also used descending numbers to avoid negative temperatures, a practical choice in Sweden’s cold climate.
It might seem odd to us now, but Celsius’s decision to put the boiling point at zero and the freezing point at one hundred made sense at the time. It helped avoid dealing with negative numbers, which weren’t as important in Sweden, where temperatures rarely got as high as the boiling point of water. Even though this approach was unusual, it was a big step forward in measuring temperature. Celsius continued to use his inverted scale until he passed away in 1744.
The Celsius scale we use today was developed after Celsius’s death. In 1745, Uppsala University started using the familiar scale, thanks to instrument maker Ekström. Another professor, Carl Linnaeus, also claimed to have flipped the scale for his greenhouse thermometer, helping to shape the Celsius scale we know. Around the same time, a French scientist named Jean Pierre Christin independently created a thermometer in 1743 that used zero degrees for freezing and one hundred degrees for boiling. Despite this, the scale became known as Celsius, partly because a popular 19th-century chemistry textbook by Berzelius mistakenly credited Celsius with its creation.
Even though Celsius didn’t create the scale that bears his name, his work in temperature measurement was incredibly important. At a time when many different temperature scales existed, Celsius set reliable fixed points for measuring temperature. He showed that melting snow stays at a constant temperature and explained how boiling points change with air pressure, helping to create a universal system for measuring temperature.
Today, the Celsius scale isn’t just based on the freezing and boiling points of water. It’s linked to the Kelvin scale, which is defined by the triple point of water—where solid, liquid, and gas all exist together at exactly 273.16 Kelvin. This modern definition allows for more precise temperature measurements, with pure water boiling at 99.974 degrees Celsius and freezing at -0.0001 degrees Celsius.
The Celsius scale is the result of many scientists working together over the years. While Anders Celsius played a key role in setting up reliable ways to measure temperature, the scale itself evolved thanks to contributions from many people. The “C” in Celsius stands for not just one person’s legacy, but the collective achievements of the scientific community in creating a reliable and widely accepted system for measuring temperature.
Create a timeline that traces the history of the Celsius temperature scale. Include key events such as Anders Celsius’s original scale, the transition to the modern scale, and the contributions of other scientists like Jean Pierre Christin and Carl Linnaeus. Use drawings or digital tools to make your timeline visually engaging.
Conduct an experiment to observe the freezing and boiling points of water. Measure the temperature at which water freezes and boils using a thermometer. Compare your findings to the modern Celsius scale and discuss any differences you observe. Consider factors like air pressure and purity of water.
Practice converting temperatures between Celsius, Fahrenheit, and Kelvin. Use the formulas: $F = frac{9}{5}C + 32$ and $K = C + 273.15$. Solve problems where you convert temperatures from one scale to another, and discuss why understanding these conversions is important in science.
Engage in a role-play activity where you and your classmates debate the merits of different temperature scales from the 18th century. Take on the roles of Anders Celsius, Jean Pierre Christin, and other scientists. Discuss why each scale was developed and how it contributed to the evolution of temperature measurement.
Research the Kelvin scale and its relationship to the Celsius scale. Create a presentation that explains the concept of absolute zero and the significance of the triple point of water. Discuss how the Kelvin scale is used in scientific research and why it is important for precise temperature measurements.
Celsius – A scale for measuring temperature where $0^circ$ is the freezing point of water and $100^circ$ is the boiling point. – The weather forecast predicted a high of $25^circ$ Celsius today, which is quite warm for this time of year.
Temperature – A measure of the average kinetic energy of the particles in a substance. – The temperature of the classroom was set to $22^circ$ Celsius to ensure a comfortable learning environment.
Scale – A system of ordered marks at fixed intervals used as a reference standard in measurement. – Scientists use the Kelvin scale to measure extremely low temperatures in space.
Freezing – The process of a liquid turning into a solid when it is cooled to its freezing point. – When the temperature drops to $0^circ$ Celsius, water begins freezing into ice.
Boiling – The process of a liquid turning into a gas when it is heated to its boiling point. – At sea level, water reaches its boiling point at $100^circ$ Celsius.
Measurement – The process of obtaining the magnitude of a quantity relative to an agreed standard. – Accurate measurement of temperature is crucial in scientific experiments to ensure reliable results.
Kelvin – The SI base unit of temperature, where $0$ Kelvin is absolute zero, the point at which all molecular motion stops. – The Kelvin scale is often used in physics because it starts at absolute zero, making calculations simpler.
Scientist – A person who conducts scientific research to advance knowledge in an area of interest. – The scientist carefully recorded the temperature changes during the experiment to analyze the results.
Water – A transparent, tasteless, odorless, and nearly colorless chemical substance, essential for most forms of life. – Water is unique because it expands when it freezes, unlike most other substances.
Legacy – Something handed down from an ancestor or from the past. – The legacy of Isaac Newton’s work in physics continues to influence modern scientific thought.
