In nodeBook we interpret functions as derived attributes. They will be included in the data exactly as attributes, except that the values will be computed.
For example: Oxygen's atomic number is same as the number of protons. We add the attribute number of protons as a regular attribute, however for atomic number we use a function that says how to compute it. in this simple case, it is same as the number of protons. However this special attribute, will work for all the elements.
Another example: Oxygen's atomic mass can be computed by adding the number of neutrons and protons.
A Physics example: Given the position data and time of a car, we can compute the distance travelled, displacement, speed, velocity, acceleration etc. if we know the mass, then we can also compute force.
This is how functions are interpretted, and we expect the students to learn the meaning of what they are from this approach. In this way they will also know why scientists use equations, which are nothing but derived attributes.