Learn Arabic (Modern Standard): سخنت مريم الهواء في المنطاد. - Maryam heated the air in the hot air balloon.

The basic Form I verb سخن means 'to become hot' and does not take an object. By using Form II, which doubles the middle root letter (سخّن), we make the verb causative. This changes the meaning to 'to make hot' or 'to heat something'. The ت at the end makes it feminine to match the subject, مريم.

How could I use the lesson's target grammar, مما (mimma), with this sentence?

Although it is not used in this exact sentence, مما is perfectly suited to attach a consequence to this whole idea. You could say سخنت مريم الهواء في المنطاد، مما جعله يرتفع (Maryam heated the air in the balloon, which made it rise). Here, مما means 'which' or 'from what' and refers back to the entire preceding action of her heating the air.

What kind of noun is المنطاد (al-mintaad)?

It means 'hot air balloon' or 'blimp' and is built on the مفعال (mif'aal) pattern. This is a very common Arabic pattern for tools, instruments, or machines (like مفتاح for key). It takes a regular kasra at the end here because it follows the preposition في.

Why does the subject مريم only take a single vowel at the end instead of tanween?

Feminine names and foreign names in Arabic, like مريم, belong to a special group of nouns called diptotes. This means they are restricted from taking tanween (the double vowel 'nn' sound at the end). Therefore, as the doer of the verb, it takes a single damma instead of a double damma.