We present the application of scanning force microscopy using the jumping mode to investigate microtubules adsorbed to glass in air and in liquid. To fix the microtubules the glass surfaces were silanized with aminopropyl-triethoxy-silane. The observed structures ranged from disrupted microtubules in air to intact microtubules in liquid. Intact microtubules show heights between 20 and 24 nm confirming the diameter found in electron microscopy studies. The force applied by the tip was critical for the microtubule height, indicating deformation by the tip. Internal structure, corresponding to protofilaments, was found.