The thermometer turns red when i turn on my car, it's normally blue.. what does that mean

That's totally normal, that's just the sensors in you car making their self tests while starting the engine to ensure that they are working ok. It's just testing that the coolant temperature warning system if working ok, hence the red thermometer appearing. After that all the systems go back to normal and give you their true readings, and that's why it goes to blue, which means the engine is cold and just started. After a while when the engine heats up normally and has run for a few minutes, the thermometer should disappear completely. My 2005 toyota echo does exactly the same thing, and so do many newer vehicules. So nothing to worry about, it just means everything on that system is working fine and like it should.:)