ballast

«ballast» in Mova's school dictionary: Heavy material, such as stones, sand or water, put low in… — its meaning for a pupil, its sense in the lessons and examples.

part of speech

noun (ballast, uncountable); verb (ballast, ballasts, ballasted, ballasting — rare)

meaning for a pupil

1) Heavy material, such as stones, sand or water, put low in a ship or balloon to keep it steady. tree →

2) The stones laid under railway tracks to hold them in place. tree →

3) Something that gives steadiness or balance to a person or plan. tree →

sense in the lessons

In science lessons about floating and balance, ballast shows how weight low down keeps a boat upright and how submarines take in water to sink. Hot-air balloons drop sandbags of ballast to rise. Railway workers lay ballast under tracks. Phrases: "ballast tanks", "drop ballast", "take on ballast".

examples

• The ship carried rocks as ballast to stop it rolling over. tree →
• The submarine filled its ballast tanks with water to dive. tree →
• The balloonist threw out a bag of sand ballast and the balloon rose. tree →
• Grey ballast stones lie under the railway sleepers. tree →
• We added coins to the bottom of our model boat as ballast. tree →
• Weight low down acts as ballast and keeps the boat steady. tree →

note

Usually uncountable: "some ballast". Throwing out ballast makes a balloon lighter so it rises; taking on ballast makes a ship or submarine heavier so it sits lower. Do not confuse with "ballet" or "balance".

Trees and pragmatics

Every meaning and example of «ballast» parsed by Mova, each sentence with its dependency tree and frames.