Measurements may be accurate, meaning that the measured value is the same as the true value; they may be precise, meaning that multiple measurements give nearly identical values (i.e., reproducible results); they may be both accurate and precise; or they may be neither accurate nor precise. The goal of scientists is to obtain measured values that are both accurate and precise.
Suppose, for example, that the mass of a sample of gold was measured on one balance and found to be 1.896 g. On a different balance, the same sample was found to have a mass of 1.125 g. Which was correct? Careful and repeated measurements, including measurements on a calibrated third balance, showed the sample to have a mass of 1.895 g. The masses obtained from the three balances are in the following table:
Answer:
Its because the steam promotes rust
Explanation:
Water vapour tends to oxidise iron...hence promoting rust
Answer:
A variable is anything that can change or be changed. In other words, it is any factor that can be manipulated, controlled for, or measured in an experiment.
True that in the preindustrial era, settlements were more likely to be near sources of surface water than in the industrial era. The main reason being that during the preindustrial era people were dependent mostly on irrigation. For irrigation people were dependent on surface water. This was the main and basic reason.
