radioactive
part of speech
adjective (radioactive; noun: radioactivity, uncountable)
meaning for a pupil
1) Something radioactive gives off strong, invisible energy called radiation because the centres of its atoms are breaking apart. tree →
2) (informal, joking) Radioactive can describe something so unpopular or dangerous that everyone stays away from it. tree →
sense in the lessons
In science lessons radioactivity was discovered by Henri Becquerel and studied by Marie Curie, who found radium and polonium. Radioactive materials are used in nuclear power stations, in hospitals to treat cancer and take scans, and in smoke alarms in tiny safe amounts. They can be dangerous: too much radiation damages living cells, as in the Chernobyl disaster in Ukraine. Safety: warning sign is a yellow-and-black trefoil. Phrases: «radioactive waste», «radioactive material», «half-life».
examples
- Uranium is radioactive. tree →
- Marie Curie studied radioactive elements. tree →
- Radioactive waste must be stored safely for thousands of years. tree →
- The area around Chernobyl is still radioactive. tree →
- Doctors use radioactive substances to find and treat illnesses. tree →
- You cannot see, hear or smell radiation, so workers wear special badges to measure it. tree →
- In comics, a radioactive spider gave Peter Parker his powers. tree →
- After the scandal, the singer was radioactive — no company would hire him. (informal) tree →
note
«Radioactivity» is uncountable. Myth: radioactive things do not glow green as in cartoons. Trap: «radiation» also includes harmless or useful things like light and radio waves; «radioactive» is about atoms breaking apart. A small amount (background radiation) is around us all the time.
In the corpora
- The heat inside the Earth comes partly from when the planet formed and partly from radioactive elements slowly breaking down.
- Some atoms are radioactive and slowly change into other atoms at a steady rate, like sand falling through an hourglass.
Trees and pragmatics
Every meaning and example of «radioactive» parsed by Mova, each sentence with its dependency tree and frames.