old
Definition
Old is a relative term. It is used to describe something that has existed for a long time, but there is no one definition of what "long time" means.
The age of something can be measured in years, but it can also be measured in other ways, such as the number of generations that have passed or the amount of time it has taken for something to evolve.
For example, a human being who is 80 years old is considered old compared to a human being who is 20 years old. But a star that is 80 million years old is not considered old compared to a star that is 13 billion years old.
The age of something can also be measured in terms of its physical condition. For example, a car that is 20 years old may be considered old if it is starting to rust and break down. But a 200-year-old tree may not be considered old if it is still healthy and strong.
The age of something can also be measured in terms of its cultural significance. For example, a painting that is 100 years old may be considered old if it is no longer popular or relevant to the modern world. But a 10,000-year-old cave painting may be considered old but still be considered culturally significant.
How can the word be used?
Old things can also be worn out and obsolete.
Different forms of the word
Adjective: Having existed for a long time.
Noun: An old person.
Verb: To make old or older.
Etymology
The word "old" comes from the Old English word "eald," which means "having lived for a long time." The Old English word "eald" is also the source of the Dutch word "oud" and the German word "alt.".
The word "old" was first used in English in the 8th century. It was used to refer to something that had existed for a long time.
Question
What makes something old?
AQA Science Exam Question and Answer
Question:
Explain the concept of radioactive decay and how it's used to determine the age of ancient materials.
Answer:
Radioactive decay is a fundamental process by which unstable atomic nuclei transform into more stable configurations, emitting radiation in the form of particles or energy. This process occurs in isotopes with an excess of either protons or neutrons, leading to a more balanced and stable nuclear composition.
One application of radioactive decay is radiometric dating, a technique used to estimate the age of ancient materials. This relies on the known decay rates of certain isotopes, such as carbon-14 and uranium-238. As an example, carbon-14 dating is effective for determining the age of organic remains like fossils or ancient artefacts. Carbon-14 is a radioactive isotope that decays into nitrogen-14 at a known rate. By measuring the remaining ratio of carbon-14 to carbon-12 in a sample, scientists can estimate how long it has been since the organism's death.
Uranium-238, on the other hand, decays into lead-206, and this decay chain is used to date rocks and minerals. By analysing the ratios of uranium and lead isotopes in a mineral sample, scientists can calculate the time elapsed since the rock formed.
In essence, radioactive decay serves as a natural clock that helps us understand the ages of geological formations, archaeological artefacts, and even the Earth itself.