How can you tell that a white powder is salt without tasting it

Which statement describes james chadwick’s discovery.

Avariable that is not being directly tested during an experiment should be changed varied experimented controlled

An engineer decides to use a slightly weaker material rather than a stronger material, since she knows that the stronger material can break suddenly. this is an example of what? a choosing a material that will show warning before it fails b using composite materials that combine strength c using a material for multiple applications d using design techniques that increase efficiency and reduce cost