How can we see the Sun if it is made up of only gas? So I'm researching if the sun is transparent or not and have found that it is made up of gases. From what I know the gases the sun is made from are transparent. So why can we see the sun if it's made of transparent things.
 A: This has an answer on several levels.
As others have indicated, the physics reason is because the Sun itself is opaque to light; it isn't transparent.
There are many sources of opacity in the gases that make up the Sun. These arise in processes that can be classified as: bound-bound (radiative transitions between bound states in ions and atoms that occur at discrete energies); bound-free (transitions of electrons from bound to free, or ionised, states and vice-versa - e.g. photoelectric effect); or free-free (involving the acceleration of free electrons - e.g. inverse bremsstrahlung).
Bound-free and free-free processes produce absorption over a continuum and if you have enough gas, then it becomes "optically thick" (has an optical depth much greater than unity) to radiation. That is, a photon has no chance of passing unabsorbed through the Sun.
Now the next part is determining what the Sun looks like. Because it is roughly in thermal equilibrium and opaque, the sun emits (roughly) blackbody radiation. The temperature of the blackbody is the temperature of the upper layer of the Sun's gas where photons are able to escape (the Sun gets hotter as you move inwards). This is somewhat wavelength dependent, which is why the spectrum of the Sun is not a perfect Planck function. The opacity source that is mostly important here is continuum opacity due to bound-free transitions with H$^{-}$ ions (Wildt 1939). In the Sun this leads to a relationship between temperature and optical depth such that photons escape the "surface" from gas that is at around 5800K. The escaping blackbody radiation peaks (by Wien's law) in the visible part of the spectrum. This layer is what we refer to as the Sun's photosphere or visible "surface".
Why can we see this radiation? Well that's down to the development of the eye and evolution.
A: when electrically neutral, gases are transparent. the gases that form the sun are so hot that their outermost electrons have been torn loose (this is called ionization), rendering the gas electrically conductive. light cannot travel through anything that is electrically conductive, so you cannot "see" through the sun even though it is made of gas. 
to clarify: I meant transparent at wavelengths your eye uses to observe the sun. 
A: It is actually made up of plasma. Plasma means ionized gas. The Sun is a big ball of hot ionized gas and we can see it because it emits light. As Samuel said, we can see a candle flame because it is hot and it is glowing.
The main process that happens in the Sun is proton-proton fusion. There is a chain of processes in which the protons inside the Sun collide and fuse into Helium. In these processes there is a release of energy in the form of charged particles, neutrinos and light.
