We first came up with a question (or hypothesis) that we wanted to test.  We remembered to change only one variable such as the colour or size of the moth and then we placed them on a tree trunk to see which ones were most difficult to see.  We recorded our results and then made our conclusions.  We found that the smaller the moth, the less visible it was and that certain colours stand out more against the background of a tree, which is bad news if you want to stay hidden from hungry predators!  Don’t worry – no real moths were harmed during the experiment because we used paper ones to represent them instead.