In some embodiments, an apparatus includes a base structure and a tube. The tube has a first tube portion, a second tube portion substantially parallel to the first tube portion, an inlet portion, and an outlet portion. The tube is configured to have a material pass from the inlet portion to the outlet portion. The apparatus further includes a drive element in contact with the tube. The drive element is configured to vibrate the tube such that the first tube portion conducts vibrational movements out of phase with vibrational movements of the second tube portion. The apparatus also includes a sensing element, at least a portion of which is in contact with the tube. The sensing element is configured to sense deflections of the first tube portion and the second tube portion such that at least one property of the material is determined.