Term: what kind of data should we call things like 'periodic table' etc

I am not sure if this should be an English language question but to me I think it is very appropriate...

I am writing an article where I describe different types of data that scientists often use to predict the flooding incidents during a rainfall. To give you some examples, such data may include

• hydrological data (rainfall intensity, watercourse)
• urban planning data (e.g., drainage network)
• topographical data (street elevation etc)
• evaporation

For the last item, people often use a look-up table that defines water evaporation as constants under different temperature conditions. In a way, this is like things like periodic table, where attributes of chemical elements are constant and will not change; constant parameters in other science domains such as speed of light, sound, or mathematical constant pi, ... Such are not data that need to be collected during the flooding incidents, but certainly data that needed to for the prediction tasks.

What should I call such data? Scientific variables? Common sense constants? Or are there any better terms?

Thanks

Perhaps "reference data", "table data", or even just general "scientific data". If the data is specific to a particular topic, such as evaporation, then you could simply call it "evaporation data".

It is important to distinguish between constants, variables and parameters. As you recognize in your question, the constants of the periodic table are the elements, their masses, their subatomic compositions and so forth. Pi is a mathematical constant.

Nevertheless, your own question and the accepted answer fail to make the necessary distinction. Briefly:

A constant does not change. (Mass of an electron, Pi ...)

A parameter may be constant in a limited case but changes from case to case (gravitational acceleration on Earth and Moon is very different, and on earth it is constant at any point but is slightly different at other points).

A variable is something whose value changes (your example of evaporation rate).

In your case evaporation is a variable whose value is linked to another variable (temperature) by an equation in which constant parameters are used to quantify the linkage between evaporation and temperature. I note in passing that evaporation actually depends on many more variables than temperature and that there will be constant parameters for each of them.

I cannot repeat all the material here but you will find useful discussion in

Math Stack Exchange