a ruler and pan balance
a triple beam balance
Triple beam balance
A triple-beam balance scale
The most common instrument used to measure isotopes is a mass spectrometer. Mass spectrometry allows scientists to accurately determine the mass and abundance of isotopes in a sample. It works by ionizing the atoms in the sample and separating them based on their mass-to-charge ratio.
triple beam balance
Mass spectrometer would work.
a balance
A set of scales
a viscometer is used to determine viscosity(density) of a liquid.
You would determine its mass using a mass balance.
You would first determine the mass of the egg. Then you would need to determine the volume of the egg through water displacement. Then you would need to divide its mass by its volume, and that will give you the density.
Any instruments that can measure mass and length. (not at the same time, doesnt have to be the same instrument). By measuring the length, height and width of an object you can determine it's volume and by weighing it you can determine it's mass. From these results it's possible to calculate the objects density.
The answer will depend on how big the rock is.