and also note the USA profile.
School science projects are about what the student learns in techniques, methods, analysis and linking to wider research. It is not post doc standard original data. A good starting point is - how does any given factor compare with here?
Basic info that's missing is timing, is this a vacation project for autumn? What age group, or what detail level is expected? Three hives are plenty for most purposes and can be compared or averaged but what sort of access is possible? Can they be opened daily for samples? Do we have equipment like a microscope? Pollen trap? Disease treatments? Can we risk reducing crop yield? What sort of time are we putting in?
Forage based studies should be good. Pollen identification by colour and microscope samples maybe? It's finding out what your bees are bringing in and will vary for any location. Sampling week by week is possible, or if time is short does it vary over a day? By weather? Other possible questions are is the same plant providing pollen and nectar by checking what's in the honey? Does the direction they go in change? Photos of bees on the plants will always liven a presentatiion.
Quantitative data such as weighing is possible, but might result in one graph that looks a little thin. Marking drones might be fun, one colour per hive, a hundred marked and observing where they turn up. How many still around in a month? Another good opportunity for photos. Plotting colony size, counting eggs, open brood, sealed is possible but will have missed the early build up. Progress of a split or smaller unit could be interesting.
Try some queen rearing, grafting, mating nucs. Lots to learn. Compare techniques, success rates?
Varroa building up and plotting your counts are possible and might be compared with research elsewhere and general threats and disease problems. Treatment comparisons? Hygienic behaviour? Treatment resistance? Nosema assays?
Morphology studies, what is the local bee population? Dissection?
Lots of possibilities from a few photos to fairly advanced lab techniques, analysis and practical skills like microscope and handling that you can demonstrate. Good luck