Final answer:
A specimen should contain no water when imaging it with scanning electron microscopy (SEM) because water can interfere with the electron beam and cause distortion in the image. Dehydrating the specimen removes water and allows the electrons to pass through the sample for clear imaging. Dehydration also helps preserve the specimen's structure.
Step-by-step explanation:
In order to image a specimen using scanning electron microscopy (SEM), it should contain no water. This is because SEM works by scanning a beam of electrons across the specimen's surface, and the presence of water can interfere with the electron beam and cause distortion in the image. When water is present, it can lead to charging effects and blurring of the image.
By dehydrating the specimen, the water is removed, allowing the electrons to pass through the sample unhindered. This results in clear, detailed images of the specimen's surface. Additionally, dehydrating the specimen also helps to preserve its structure and prevent shrinkage or distortion during imaging.