It is an art you have to learn. Else, you suffer the consequences in waste of time, follow ups and endless but useless shouting. NOt that learning the art exempts you from these, but the frequency definitely is reduced by say, one or two instances.
What needs to be done is, withold the manna of a scientist. the Piece of Paper. Tell them the project requirements. Make them repeat. Aha! Error etected. Make them look at you. not at the sheet of paper with you. Repeat the requirements. Explain to them, in baby tongue. Keep their phone away. Keep the mouse away. try to keep the head steered in a direction away from the computer monitor. Repeat again, the requirements.
Block exit path because they tend to move a lot when not oops, when forgetting they were listening, if at all they were. Scientists dont listen. they only expound.
then try to bring them back with the award - lure them with the sheet of paper with the project outlined on it. try to make them concentrate on the requirements again.
But now they have the toy - the prize - the sheet of paper. Now all you can do is hope. Hope that your repetitive sentences somehow managed to penetrate the innumerable activities abounding in that brain and enter. Hope that the scientist will do what you want him to do with the project, and not wander off into unrelated mazes. Hope as s/he walks away that the nods and "yes"'s that you got were of understanding, and not a standard conditioned response.
Hope that you only have to repeat this once more...just ONCE more for this project.
Hope that you dont have to do it again. for any project.
And as the figure vanishes from eyesight, you sigh and look up the scientists' number on the directory and call the extension. Because you know the last two hopes are in vain. You call up to remind the project requirements to the scientist ... again....even as he talks to someone in front of him...if at all you manage to catch hold of him on phone.