Words for Wednesday ... on a Tuesday - Easter Holiday 3

In June 2019 WiseWebWoman is providing the prompts.  

Better late than never ... and before the new Words for Wednesday are published tomorrow, I continue the story where I left off last Wednesday: the first Easter holiday at Unicorn farm, Studies in magic has been taking place all through Summer holidays, Autumn week, Christmas holidays and Spring week. The Easter Holiday "term" brings with it exams and tests and new subjects.  

This week's prompts are a picture of fire
and these two groups of 5 words each:

Iceberg
Gas Pump
Cellar
Painting

Blackboard
Carrot
Doorbell
Cheese

Back on Unicorn Farm the green team met in their room, Hilde and Josta conspicuously absent. Thora came in with the two in tow. Wordlessly she pointed to the empty table in front and placed her coffee cup on the table. When everybody was seated she grasped her wand and still without a word turned to the blackboard where two 3D paintings of a hipppocampus emerged. One in their land form, and one in their aquatic form."Veronika," she snapped, and she looked up, clearly expecting an attack of some kind, "you asked, whether hippocampi normally had fish tails. As you all can see, their aquatic form do indeed have a fish tail. Now I'll have you all draw these two forms in your notebook, and write down the differences you see. You may add any observations you did today, while feeding the live specimens carrots, stroking, examining and not least riding them." she said with a furious glance at Hilde. All twelve heads bowed over notebooks; pencils, crayons, pens, and other writing utensils were busy at work.
Thora meanwhile stood at the blackboard, emitting a cold, an iceberg would have been proud of; normally she would have been passing around, looking over the shoulders of the apprentices, correcting a detail here, praising a perfect line here or a good turn of phrase there. The atmosphere in the classroom was so quiet, cool and fiercely concentrated, that they all jumped when the doorbell rang.
Torben came in, carrying an enormous square board with a big sheet of paper tacked to it.
Everybody looked at him. "We're having the traditional Easter Fire a week from now," he said, holding the board aloof. "Whomsoever wants to jump through the fire or stand in it, must write their names on this board which will be hung in the barn under the hayloft."
Susan, Knud, Terje and Veronika looked bewildered. In normal circumstances they would have been asking their neighbours what an Easter fire was, and why someone would want to jump through it or stand in it; but they dared not face Thora's wrath.
"Class dismissed! Hilde and Josta, you are in the cellar by two o'clock!" Thora said, turned around and left.

"What's an Easter fire, and why would anybody want to stay inside it?" It was Veronika who expressed the question burning in their minds. Hilde began giggling, then shut her mouth and left.
All the apprentices whose families were wizards and witches began explaining at once.
"Don't you know .." Kalle began
"We do it every year ..."  Marja said in a loud voice.
"It's a competition ..." Kirstin added.
"We celebrate the victory ..." Rosa said
"Stop it," Torben said. "Nobody's able to hear much less understand anything. You," he said pointing at Kalle, "you seem to know what you're talking about. You tell those of non-magic parentage what it's all about." Torben then hefted the sign and left.