There's a difference between faith and trust.
If I'm going to believe in (say) leprechauns, I have to have faith in order to do so, because I have not observed any evidence to support their existence. I have heard stories and claims and the like, but I haven't directly observed any evidence, however weak.
In the case of science, I may have to start out with faith that what I am sensing is what's actually there, but the longer I do that, the more predictions I can make about the world around me. E.g. that if I reach out what I believe to be my 'fingers', in what seems, to my limited senses, to be a sufficient 'distance', in what I perceive to be that what-I-shall-call 'direction', I will experience something that I name a 'feeling' of the wall I encounter.
And when I do encounter the wall, my prediction has been provisionally verified (pending further testing). Every time I test my senses and my predictions (at least seem to) come true, then I go further down the road from 'faith' to 'trust' in my perception of the world around me, to the degree that I act as though what I believe - i.e. that what I see around me is 'real' - is true.
Faith is belief in something despite a lack of evidence, or worse, in the face of evidence to the contrary. Trust occurs when you believe in things (or people) that either you have tested to your satisfaction or that someone you trust in turn has done so (and that chain of trust can be arbitrarily long). Trust is harder to gain and easier to lose, but ultimately, I think, more valuable and useful.