No single instrument; it's actually very expensive to do quality control and product testing.
You could test for fat concentration, but that could be fooled by adding other oils.
You could test for protein, but that could be fooled by adding proteins, or even just by adding chemicals that come up the same on the tests (there are many)
You could test density, but for the same reasons, this won't tell you either.
You could take the milk to a microscope and do a visual confirmation, but this would be very time consuming and random, and wouldn't pick up solutes.
You could test for poisons and other chemicals individually, but for each one you test, that's more time and money spent. Test for lead, test for every possible pesticide.
You could just feed a rat on it and see if the rat dies (the old method); but that will only tell you if it's extremely poisonous (might still kill a human without killing a rat).
A lactometer measures the density of milk. Whole milk has a specific density typically around 1.03g per liter. When the density of milk is lower than the expected density, it means that water was added to the milk. Farmers are typically paid per liter of milk and adding water could increase the volume that the farmer is paid for. Adulteration with water will also lower the butterfat, protein and solids value.
Both lactometers and viscostiymeters are instruments used for measuring the purity of milk.
Purity of milk is measured in a couple of ways: antibiotic test; added water by specific gravity or infrared technology.
Lactometer
lectometer
A measuring cup, of course!
well you just measure it. (:
the tool you use to measure milk in your cereal would be the measuring cup
Lactometerlactometer
This instrument is a balance.
A tiltmeter measures changes in the tilt of the earth. :)A tiltmeter is an instrument that measures changes in the tilt of the earth. :)
A calorimeter measures heat. In contrast, a thermometer measures temperature.A thermometer bolometer - an instrument that measures heat radiation; extremely sensitive calorimeter - a measuring instrument that determines quantities of heatHeat is measured with a ThermometerThermometerThermometer or calorimeterThermometerthermometerHeat is measured with a thermometer.
A thermometer measures molecular energy.
a calender
ruler
An aeroplane