bumpiness

Everyday

1. Bumpiness is how bumpy something is: how many lumps, holes or rough parts a surface has. tree →
2. Bumpiness is also the feeling of being shaken up and down, like on a rough road, a bumpy flight or a choppy boat ride. tree →

In the lessons

In science and maths it describes how rough or smooth a surface is, for example when testing how far a toy car rolls on carpet, sand or a smooth floor (more bumpiness means more friction). In everyday life it describes rough journeys. Phrases: the bumpiness of the road, a bit of bumpiness.

Examples

• The bumpiness of the old track made the bike rattle. tree →
• The pilot said to expect some bumpiness during the flight. tree →
• We measured how the bumpiness of the surface changed how far the car rolled. tree →
• The bumpiness of the lane made Dad drive very slowly. tree →
• Sandpaper has more bumpiness than glass, so there is more friction. tree →
• The baby slept through all the bumpiness of the bus ride. tree →

Note

Uncountable: no plural, no «a» (say «some bumpiness» or «the bumpiness»). Made from bumpy + -ness; the y changes to i: bumpiness. Opposite: smoothness. On planes the proper word for bumpiness is turbulence.