Just to compare them and not to weigh them, then you could use a seesaw.
balance
It is used to compare masses.
A student could use a digital scale or a balance to compare the masses of two small rocks. Simply place one rock on the scale, record the mass, then repeat with the other rock to make the comparison.
Compare their weights when they're both in the same gravitational environment ... on the surface of the Earth, for example. Under those conditions, their weights will be directly proportional to their masses.
mass of electron = 1/1836 mass of proton (or neutron)
grams
A student could use a balance scale to compare the masses of two small rocks. Place each rock on one side of the scale and observe which side is heavier to determine which rock has a greater mass.
A balance or a scale can be used to compare the masses of two objects. By placing the objects on either side of the balance or scale, you can visually determine which object has a greater or lesser mass.
0.8 kg and 800 g are equivalent masses.
Why should you compare activities for applicability
They have different masses, electrical charge, dimensions, life time, spin etc.