Sometimes, dyspepsia is a more sudden, noticeable (acute) sensation. Depending on the cause of the dyspepsia, people may have other symptoms such as a poor appetite, nausea, constipation, diarrhea, flatulence, and belching. For some people, eating makes symptoms worse. For others, eating relieves symptoms.
An X-ray machine is essentially a camera. Instead of visible light, however, it uses X-rays to expose the film. X-rays are like light in that they are electromagnetic waves, but they are more energetic so they can penetrate many materials to varying degrees.
X-rays are very high frequency waves, and carry a lot of energy. They will pass through most substances, and this makes them useful in medicine and industry to see inside things. X-rays are given off by stars, and strongly by some types of nebula. An X-ray machine works by firing a beam of electrons at a target.