Investigate the school grounds to see where there is electricity being used. Make a simple anemometer to see where the best place would be to build a wind turbine.
Using a seed tray investigate the requirements of different seeds and plants and create a mini-allotment to grow in the classroom and then later transplant outside.
Use your ears, nose, mouth, eyes and fingers to investigate the local park or school grounds by pretending you have crash landed on a lost planet and have to send information back to NASA