What do not have a definite shape or volume in sience?

Significant figures are digits read directly from the measuring instrument plus one more digit, which is __ by the observer.

If you chip a tooth, most likely you will go to the dentist to have the missing material filled in. currently the material used to fill in teeth is a polymer that is flexible when put in, yet is hardened to the strength of a tooth after irradiation with blue light at a wavelength of 461 nm. what is the energy in joules for a photon of light at this wavelength?

Which of these expressions are correct variations of the combined gas law? p1v1t2 = p2v2t1 both