<p>Use food coloring, not some weird chemical reaction. If you drink enough green beer, it could cause your <a href="https://www.thoughtco.com/drinking-green-beer-turn-pee-green-607374" data-type="internalLink" data-component="link" data-source="inlineLink" data-ordinal="1">urine to turn green</a>. I imagine you might see even see leprechauns, though that would be from the <a href="https://www.thoughtco.com/gallery-of-e-name-chemical-structures-4122744" data-type="internalLink" data-component="link" data-source="inlineLink" data-ordinal="2">alcohol</a>, not the coloring.</p>Wasn&#39;t there green fire in Disney&#39;s 1959 movie &#34;Darby O&#39;Gill and the Little People&#34;? If not, there should have been. Eldritch green fire screams Irish and St. Patrick&#39;s Day.Use chemistry to make your very own pot of gold by changing the color of pennies from copper to silver and finally to gold! Some say leprechaun gold vanishes before you can spend it. You can&#39;t spend this gold either, but that doesn&#39;t make the project any less fun.Eat fried green eggs for breakfast. They look a little strange, but most people would prefer it to cabbage and corned beef. Actually, this project uses cabbage juice to turn the eggs green, so it&#39;s highly appropriate.<p>... or play a prank on someone else. If you <a href="https://www.thoughtco.com/drinking-green-beer-turn-pee-green-607374" data-type="internalLink" data-component="link" data-source="inlineLink" data-ordinal="1">drink enough green beer</a> (or anything containing green food coloring) this can be one of the consequences. However, green food coloring is not the only way to color urine green.</p>The non-permanent way to achieve this is to use cosmetic hair spray. You can use chemistry to impart a lasting shade of green.Make green slime and set it someplace tricky to try to catch a leprechaun! It&#39;s like a humane glue trap, right? Personally, I&#39;ll be highly surprised if you manage to catch a leprechaun using green slime, but it&#39;s worth a try.If you put green food coloring in a white flower&#39;s water, you can get a pretty green flower. It&#39;s also possible to apply a little chemistry know-how to make a glowing green flower for St. Pats.