Why is the sky blue?

The sky is blue because of light passing through it. Light from the sun enters Earth's atmosphere, the the layer of gases (air) that surrounds Earth, and hits the atoms and molecules in the air. The light from the sun is made of many colors of light that, when we look at them together, look white. 

Source: Hyperphysics

This is called scattering. Light is an electromagnetic wave that can come in many colors (see What is Color?). What we call "color" refers to the wavelength (and frequency) of light. The concept of wavelength is described in What is Color?. Certain wavelengths, or colors, of light are scattered more often than others. Blue light (shorter wavelength) is scattered more frequently red light (longer wavelength). This scattered light goes in all directions, including into your eye. 

Consequently, during the day, the sky appears blue since the scattered blue light, when you look at the sky not around the sun, you are seeing this scattered blue light. At dawn and dusk, you are looking more directly in the direction of the sun. Much of the blue light that the sun sent to earth is scattered in other directions, so less of the blue light reaches you. The light that reaches you tends to be orange and red. Consequently, the sky looks red or orange.

What is an electron microscope?

A microscope is similar to a telescope or a pair of eye glasses. All microscopes, telescopes, and glasses have something in common, lenses. A lens is normally a curved piece of glass that bends the light that passes through it, think of a magnifying glass. Similar to how eye glasses makes things that are blurry and how telescopes make things that are far away seem close up, microscopes make things that are very small seem larger.
Below is an example of how light waves bend through different kinds of lenses:

Source: http://www.shokabo.co.jp/sp_e/optical/labo/lens/lens.htm

Light microscopes used in a number of areas such as medicine, science, and engineering. Microscopes that use light are powerful tools, but they cannot see the very small objects like atoms. For this, we can use an electron microscope, a microscope that uses electrons rather than light.

Source: http://www.microscopy.ethz.ch/lens.htm

Since electron microscopes do not use light, it also does not use typical lenses. Instead, it uses magnets. Just as lenses bend lights, magnets will make electrons bend. Since you cannot see electrons with your eyes, we use some other equipment to make a television signal that shows an image on a tv screen. The tv at your home uses electrons to produce an image as well. An electron microscope is kind of like a tv attached to some magnets!

What are scientists like?

On TV, scientists are often shown as extremely smart people separate from the rest of society who speak in terms that few people understand. Big Bang Theory allows the scientists on the show to at least be a part of the rest of society and humanizes them, although they still fall into most stereotypes of scientists(stereotypes are exaggerated characters often used to make fun of a group). These are just stereotypes. Scientists are a diverse bunch of people. What unites scientists is an interest in how at least one aspect of the world works. Scientists like to ask questions, come up with ideas about the answers to these questions, and test these possible answers, called hypotheses. A hypothesis must be testable. 

For example, my office mate enjoys photography, soccer, and watching MMA. Another person in my research group enjoys listening to smooth jazz and movies. I play the saxophone (alto and tenor), enjoy playing most sports, love science fiction (especially Stargate SG-1), and enjoy debating public policy. This is only a part of my research group. There is even more diversity in our larger collaboration and in science, in general. Scientists come from all races and are of all genders. Curiosity unites us.