A poltiergiest is a spirit able to move and disturb things or people.
A appartion is able to communicate with people and is easily seen in photo's as fog or orbs.
Poltiergiests
Poltiergiests are known as the noisy spirit. They do attract mostly to children going through puberty. With thier ability to move things most people do not like them and try to stay away from them. As usual though you can ask them firmly to go away. Though some spirits are the works of the Lord, most of them from my expierience are works of the Devil and have a strong sense of the bad guy syndrome. If they stay consult a priest to bless your house.
Apparitions
Apparitions can be seen by the naked eye, and they can be seen in photos. Apparitions are the easiest to be seen in pictures. They can be orbs or even fog. These things in your picture though are not always triggered by ghosts. Most of them in fact are dust on the lense of your camera, or bad lighting. Even a reflection can mess up the picture. Apparitions can be heard though. If you listen hard enough you might be able to help them too. These are the most common, and are probably the ones you see "floating" around your house.
Fun Info
Have you ever seen something out of the corner of your eye, but when you look its not there? Did you know something is actually there!!?? You really are seeing something, but it can not be seen in color! The real question is though, what are you seeing???