The aim for students in the MINERvA masterclass will be to estimate the size of the carbon nucleus from momentum transfer. In an event, a neutrino might strike a neutron in the carbon nucleus, which is ejected as a proton plus a muon due to the momentum of the neutrino. We can measure the momenta of the two objects in the x- and y-directions, perpendicular to the neutrino beam, which is in the z-direction. We can use this to infer px and py for the neutron before it encountered the neutrino. If we repeat this enough, we can plot the distributions of px and py and measure their uncertainties. We then use the Uncertainty Principle to find the uncertainties in x and y, which should be in the same range as the diameter of the carbon nucleus.