How to make ammonia from urea? The chemical formula of urea is $\ce{CO(NH2)2}$ or is sometimes written as $\ce{CH4N2O}$. How would I decompose or precipitate the $\ce{CO}$ from urea to get ammonia? I know that in the olden days people used to make gunpowder (potassium nitrate) and ammonium nitrate from human urine, which was made by reacting ammonia and nitric acid, so it should be possible. (Just as a side note: this is for a high school chemistry project, I am not attempting to make explosives out of this).
Short answer: use crushed watermelon seeds (urease)
Combine urea in solution with urease, get some ammonia with carbamate intermediary, which rapidly decomposes to ammonia and carbon dioxide.
$$\ce{(NH2)2CO + H2O -&gt;[urease] NH3 + H2NCOOH -&gt; 2NH3(gas) + CO2(gas)}$$
Of course the ammonia gas dissolves in the water and increases the pH.
Sources:

https://www.hemmaodlat.se/research/citrullus%20lanatus%20seeds%20as%20a%20urine%20catalyst%20for%20anthroponic%20use.pdf
https://en.wikipedia.org/wiki/Urease
https://en.wikipedia.org/wiki/Ammonia_volatilization_from_urea