In the Herbology classroom, walk into the room with four flower pots on a table and notice a bucket hanging on the ceiling above the dancing water can. Cast Wingardium Leviosa on the bucket and let it hover over each of the pots. It will pour dirt into them. Then, cast Wingardium Leviosa on the water can and hover it over each dirt-filled pot until it spews water on them. Spikey-plants will grow and you will receive Discovery Points. Then, go to the entrance of the Herbology room and walk forward into the dead-end hallway directly in front of the door in the classroom. You will see a rope hanging up in a corner. Use Accio. It will air out the room and give you Discovery Points.