In an electron microscope, the image is produced with the help of electron radiation, which has the advantage that significantly smaller structures can be detected. In this form of microscopy, electrons are directed through electron lenses and shot at the object. This process must take place in a vacuum so that the electrons can reach the object barrier-free. Finally, a detector processes the signals and displays the image.
Explanation for children: In electron microscopy, electrons are shot at the living creature and this creates an image. Imagine electrons as tiny balls: When a ball hits a living being, a clever computer recognizes it and creates the image. To ensure that electron shooting works perfectly, there must be no other things in the air. The great advantage of the electron microscope is that you can look at structures that are millions of times smaller than a millimeter.