ddt
part of speech
noun, abbreviation (DDT, uncountable)
meaning for a pupil
1) DDT is a strong chemical insecticide (short for dichlorodiphenyltrichloroethane) that was once sprayed widely to kill mosquitoes, lice and crop pests. tree →
2) DDT was found to harm wildlife, especially birds of prey, whose eggshells became thin and broke; it was banned for farm use in many countries, though small amounts are still used against malaria mosquitoes in some places. tree →
sense in the lessons
In science and history lessons DDT is a key example of how a chemical can build up along a food chain (bioaccumulation): from insects to fish to eagles and ospreys. Rachel Carson's book «Silent Spring» warned about it and helped start the environmental movement. It also saved many lives by controlling malaria and typhus. Phrases: DDT spray, banned DDT, the effects of DDT.
examples
- DDT was sprayed on fields to kill insects. tree →
- DDT made birds' eggshells too thin. tree →
- Rachel Carson wrote about the dangers of DDT. tree →
- DDT builds up in animals higher up the food chain. tree →
- Many countries banned DDT for farming. tree →
- Bald eagles recovered after DDT was banned in the USA. tree →
- DDT was once used to kill lice on soldiers. tree →
- Some countries still use DDT inside homes to fight malaria. tree →
note
An abbreviation: always written in capitals, DDT, and said letter by letter, «dee-dee-tee». Uncountable: «DDT is», not «a DDT». The full chemical name is long and hard; pupils are not expected to remember it. It is a good example of a trade-off: helpful against disease, harmful to wildlife.
Trees and pragmatics
Every meaning and example of «ddt» parsed by Mova, each sentence with its dependency tree and frames.