Can you look at something without affecting it in some way?

You are walking in the woods and you stop and stare at a tree. Is that tree affected by your observation of it, or does it just go along living it's happy little tree life without having ever known you watched it?

of course a profound effect if your cat is wrestling said tree!

The Observer Effect

It is not possible to observe any object without changing it in some way. Light is shadowed by your slight movement, for instance, or an ever so small change of direction of air because you came upon the object in order to see it. The effects of your observation may be negligible, however the object still experienced a change. The protons and light used by an electron microscope would move the electron. When you watch a field of antelope on the Serengeti the animals will act differently. A doctor asking a patient questions is affecting her- she may be trying to hide a medical fubar like the fact she had a cigarette last week after 5 years of having quit. Or she is nervous so will sweat and her pulse will rise. If I ask you something today- I'm in a good mood, we are at ease and comfortable, you'll give me an answer. but if I ask you the same question next week after we are having an argument and upset with each other, your answer might be slightly or even completely different.

This is why scientists work very hard trying to observe without interfering as little as possible. But no matter how seemingly insignificant, there is still a change.