In the Herbology classroom, go inside the room with four flower pots on a table. You will see a bucket hanging on the ceiling above the dancing water can. Wingardium Leviosa the bucket and let it hover over each of the pots to pour dirt into them. Then Wingardium Leviosa the water can. Hover it over each dirt-filled pot until it spews water on them. Spikey-plants will grow. You will receive Discovery Points. Then, go to the entrance of the Herbology room. 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.