In the third episode of the video series “Measured World”, Metrosert’s quantum technology coordinator Nataly Dubbelman introduces the candela. This short video, dedicated to the 150th anniversary of the Metre Convention, offers an overview of the unit of luminous intensity and explains why accurate light measurement is so important in our daily lives.
“We’re used to light being always present – in addition to sunlight, there are streetlights, smartphone screens, and car headlights. But have you ever considered how precisely the parameters of these artificial light sources are determined? To ensure that the light is sufficient but not blinding, science uses the international unit of measurement – the candela,” Nataly Dubbelman explains in the new episode.
The candela is the international unit of luminous intensity that describes how much visible light is emitted by a source in a specific direction. “The name ‘candela’ comes from the Latin word candela, meaning candle. Indeed, the flame of a regular wax candle could be roughly equivalent to one candela, but nowadays we’re more often talking about LED lights and lasers,” Dubbelman notes.
When the Metre Convention was signed in Paris in 1875, the candela was not originally among the international units of measurement. It wasn’t until the 1940s, when the need for accurate light measurement increased and scientific advancements made it possible, that the candela was added to the International System of Units (SI). “Thanks to this, we can be sure that the light surrounding us is accurately measured and safe,” Dubbelman explains.
Metrosert’s researchers are developing the national standard for optical quantities to ensure the accuracy and reliability of light measurements in Estonia. “Our role is to make sure that the measuring devices used in Estonia are always properly calibrated and their readings are comparable with those of other countries,” Dubbelman adds.
Although the role of the candela in everyday life might go unnoticed, it affects us all – whether it’s safe traffic conditions, clear displays, or a comfortable working environment.
The 150th anniversary of the Metre Convention is a great opportunity to raise awareness about the importance of metrology and measurement in both science and everyday life. The engaging video series “Measured World” provides an in-depth look at SI units and the many facets and future directions of metrology. The series features experts from the field who explain how precise measurements contribute to our daily lives and the broader development of the world.