user: I'm conducting an experiment with four objects of different materials and need to calculate their densities. The metal cube weighs 500 grams and takes up 100 cc, the plastic sphere is 200 grams and 50 cc, the wooden block is 300 grams and has a volume of 75 cc, and the glass cylinder is 400 grams with an 80 cc volume. Could you determine the density for each one?

Available functions:
name: calculate_density
description: Calculates the density of an object.
parameters: type: dict
properties: mass: type: float
description: The mass of the object, in kilograms.
volume: type: float
description: The volume of the object, in cubic meters.
required: mass
volume