Season 1, Episode 21:
Spartan Crafts Club
Senku: When you want something to burn, what do you do?
Chrome: Feed it a ton of extra air with a blowing machine.
Senku: So what do you do to keep something from burning?
Making cell phones takes a lot of materials and tools. Senku begins by upgrading their equipment using the waterwheel Chrome and Kaseki invented and built together.
Feats of Science:
- Lead-acid battery.
- Hydro-powered furnace blowers.
- Pickling.
- Light bulbs.
- A Christmas tree!
- Electric miner's headlamp.
- Vacuum tubes.
Tropes:
- Christmas Episode: Downplayed. The science team decorates a tree with light bulbs just in time for the holiday.
- Cue the Sun: During the sunrise, tungsten is discovered!
- Failure Montage: An even more brutal one than usual. Vacuum tubes are especially difficult to make.
- Hard-Work Montage: Preparing for the winter and doing SCIENCE.
- Old-Fashioned Fruit Stomping: Ruri and Kohaku look so cute doing it.
- Training Montage: Kohaku whips the fighters into shape.
- The Stoic:I don't have time to sulk.— Senku
- X-Ray Sparks: Ginro's electrocution convinces everybody that the batteries indeed store a lot of energy.