Fireworks

What it is

You build a 3 inch firework in cross section, then fire it. The colors are real chemistry: strontium burns red, barium green, copper blue. Blue is the hard one for the same reason it is hard in real life, the copper only holds its color in a narrow temperature band and any fuel you add to brighten it washes it out.

How it works

Click inside the shell to place stars, pick a metal salt, add magnesium or titanium if you want it brighter or sparkier. Fire it. Where you put a star in the shell is where it lands in the sky. Then build a whole show on a timeline, pick a job, and see if the crowd stays with you.

• 94 m up, about 60 m across, the numbers a real 3 inch shell hits
• You hear the break three quarters of a second after you see it
• Four metal salts, two fuels, five jobs with a budget each