Science investigatory project for grade 6 in the Philippines?

A suitable science investigatory project for grade 6 students in the Philippines could be exploring the effects of different fertilizers on plant growth. Students can set up an experiment using three groups of plants: one with organic fertilizer, one with chemical fertilizer, and one with no fertilizer. They can measure and record the growth of the plants over several weeks to analyze which type of fertilizer promotes better growth. This project not only teaches scientific methods but also emphasizes the importance of sustainable practices in agriculture.