1)Consider a beam of electrons in a CRO striking the phosphor screen.How does the uncertainity principle pan out here? Technically, we are getting the exact position of the electron due to the point made on the screen.And, we can most certainly calculate the velocity by estimating the time in which the electron went from the cathode to the screen.So, both momentum and position are known. 2)Consider a gas enclosed in a container(high density,so wave functions overlap).What is the reason here for the uncertainity in the gas molecules ?Because , as such we are not interacting, or measuring the position of each molecule explicitly. We have just left the gas in the container independent of any more interference. I know my questions may sound elementary to some but I'll be grateful for any clarifications.