DIY Science & Engineering · School Edition
13 School-Inspired DIY Inventions That Look Impossible — From a Robo Bug to an Iron Man Blaster
Build Count
13 inventions
Estimated Cost
$1 – $20 each
Inspiration
School Science Class
Difficulty
★★☆☆☆ Easy–Medium
Overview
Presenters Ethan and Max recreate a series of inventions inspired by things you could theoretically build at school — using only household materials, recycled packaging, and a bit of creative engineering. The video escalates from a simple pencil crossbow all the way to a hydraulic Iron Man blaster, touching on physics concepts like air pressure, resonance, refraction, combustion, and stored mechanical energy along the way.
Despite the casual, comedic format, each build is genuinely functional and documented with real test results — a hand-powered fan that out-blows a $100 Dyson, a battery cannon that punches through 100 layers of paper, and a DIY blender capable of shredding a PSA 10 Pokémon card.
Pencil Crossbow
Rubber-band tension launcher using pencils and a binder clip trigger
Robo Bug
Motor + battery + LED + paper clip legs — a crawling micro-robot
Hand-Powered Fan
Skewer, popsicle sticks, bottle, and a rip cord — beats a $100 Dyson
Smoke Bomb
Tennis ball shell, sugar + stump remover + baking soda + dye
Rubber-Band Plane
Cup propeller, skewer body, rubber-band engine — actually flies
Hologram Projector
45° plastic lid over your phone screen creates a floating-image illusion
Matchstick Gun
Clothespin spring trigger, matchstick ammo — can fire burning rounds
DIY Soda Machine
Air pressure dispenses three soda flavors from a cardboard box
Match Whistle
Two matchsticks + rubber band — creates a loud high-pitched note via resonance
Lava Lamp
Light bulb filled with baking soda, vegetable oil, dyed vinegar
Battery Cannon
Battery heat-ignites matchstick powder; triple-barrel version fires three rounds
DIY Blender
Coke-can blades + Pringles can + small motor — blended a $100 Pokémon card
Iron Man Blaster
Hydraulic popsicle piston + marker barrel + Coke can shell — rises on command
Materials List
Most items can be sourced from your recycling bin, a dollar store, or a craft supply shop. Combustion-related builds require adult supervision and outdoor space.
Pencils, popsicle sticks, skewers
Rubber bands (various sizes)
Small DC motor + 9V / AA batteries
LEDs + basic wire + paper clips
Tennis ball + plastic bottle caps
Stump remover (potassium nitrate)
Sugar + baking soda + food dye
Plastic cups + toothpicks
Transparent plastic lid (hologram)
Clothespins + safety matches
Cardboard box + straws + piping
Coke/Pringles cans + glue gun
Light bulb + vegetable oil + vinegar
Syringe + marker barrel (Iron Man)
Tin foil + metal tube (cannon)
Tin can + tea candle (oven)
Reference Video
Source: YouTube · Original Video · For educational reference only
Safety & Warnings
Read before attempting any of these builds
- Always ask a parent or guardian before building anything on this list. Several builds involve fire, combustion, sharp tools, or electrical components.
- The smoke bomb, battery cannon, and matchstick gun all involve controlled combustion. These must be built and tested outdoors, with water nearby and adult supervision at all times.
- The smoke mixture (potassium nitrate + sugar) is highly flammable before baking soda is added. Do not skip the baking soda — without it, you have rocket fuel, not a smoke compound.
- Do not inhale smoke from the smoke bomb or cannon. Evacuate the area immediately after ignition.
- The Robo Bug and battery cannon involve electrical components. Never short-circuit a battery, and keep wiring away from flammable materials.
- The DIY blender uses sharpened can edges. Use gloves when cutting or handling metal. Keep fingers away from the blade assembly at all times.
- This content is for educational purposes only. Always comply with local laws and school regulations.
Build Guide
Pencil Crossbow
Cross two pencils and bind them tightly with rubber bands to form the frame. Thread another rubber band lengthwise across the front to act as the bowstring. Load an ink cartridge as your bolt, pull back, and release. Simple, surprisingly powerful, and made entirely from a pencil case.
Robo Bug
Attach a small vibration motor and battery to a pin or coin as the body. Solder or tape on two LEDs for eyes. Unfold paper clips and bend them outward to create six legs. A dab of hot glue holds everything in place. When powered on, the motor's vibration makes the bug scuttle unpredictably across flat surfaces.
Hand-Powered Fan
Drill two holes in a plastic bottle and two through a popsicle stick. Push a skewer through the stick to form a propeller cross. Thread a length of string into the bottle, tie it to the skewer, then loop the bottle's ring around the string to make a rip cord. Pull hard — the wound string spins the blades at remarkable speed. In a live test it visibly out-blew a $100 bladeless fan using dry ice as a tracer.
Smoke Bomb
Cut open a tennis ball to use as the shell. Build the trigger by folding a match striker strip over a keyring with matches sandwiched inside — pull to ignite the wick. For the smoke compound, mix equal parts potassium nitrate (stump remover) and sugar, then add a small amount of baking soda to slow the burn rate and prevent it becoming a flare. Add colored dye for a tinted cloud. Fill the shell, seal with the trigger ring, and pull only when outdoors with a clear exit path.
Rubber-Band Plane
Plastic cups are slightly curved, which makes them natural propeller blades — attach two to a toothpick and fix in a paper clip hub. Glue skewers together for the fuselage and link the propeller to the rear with a chain of rubber bands. Cut and glue cardboard wings and a tail fin. Winding the propeller stores tension in the rubber bands; releasing it drives the plane forward.
Hologram Projector
Cut a semicircle from a clear plastic lid and angle it at 45° over your phone screen, held in place with a small piece of tape. Play any video with a black background on the phone beneath it. The transparent plastic acts as a partial mirror — it reflects the 2D screen image at an angle that makes the image appear to float in mid-air. Not a true hologram, but a classic Pepper's Ghost illusion executed with one piece of recycled plastic.
Matchstick Gun
Mark and cut the clothespin body with an X-Acto knife, then use additional clothespin tips to build up the handle. The trigger is a reverse-mounted spring. Push a matchstick all the way into the barrel channel — it self-loads. Press the spring to fire. An optional matchbox drum can be glued to the side for decoration. Flaming rounds are possible by lighting the matchstick head before inserting.
DIY Soda Machine
Saw the tops off three used soda bottles and attach them to short pipes. Feed each pipe through the lid of a full soda bottle, then insert a straw alongside the pipe in each lid. When the bottle is inverted inside the cardboard box, the straw lets air in — atmospheric pressure pushes the liquid up the pipe and out into your cup. Three bottles give three flavors; a fourth unlabeled tap can be a mystery. The principle is identical to how a straw works when you suck on it.
Match Whistle
Place two matchsticks side by side with a tiny gap between them and wrap a rubber band tightly around both ends to hold them parallel. Blow a sharp puff of air through the gap — the surfaces vibrate rapidly as air forces them apart and together, generating a loud, high-pitched note. The narrower the gap, the tighter the resonance and the louder and higher the pitch. The video also features an ancient Aztec skull whistle that reportedly produces a sound intense enough to shatter glass.
Lava Lamp (Light Bulb)
Add four teaspoons of baking soda to the inside of a clear light bulb. Fill it with vegetable oil. In a separate container, mix white vinegar with food dye in whatever color you want, then carefully pour the mixture into the bulb. The acid-base reaction between the vinegar and baking soda produces CO₂ bubbles that push the colored droplets through the oil — creating a churning, alien-planet lava effect. No heat required; the chemistry does all the work.
Battery Cannon
Wire batteries together to create a resistive heating element inside a metal tube — the same principle as a battery cannon from the previous JT video. Ground matchstick heads into powder for propellant, then scrunch tin foil into a cannonball. When current flows, the element heats enough to ignite the powder and expel the foil ball. In testing, the single-barrel version punched clean through 100 sheets of paper. The triple-barrel version fires three rounds in rapid succession.
DIY Blender
Score and fold a drink can into blade shapes, then skewer the blades together and press-fit them into a Pringles can as the blending chamber. Hot-glue a small DC motor to the lid and connect it to a battery with a switch. Lower the lid assembly into the Pringles can and you have a functioning blender. Test results: shredded McDonald's fries, disintegrated a cream bomb, and destroyed a PSA 10 graded Pokémon card. Use thick gloves when handling the sharpened can edges.
Iron Man Blaster
Build the hydraulic brace by gluing popsicle sticks into two X-shapes and threading a syringe through the joint — pushing the syringe plunger extends the mechanism. Use a marker as the barrel for the shooter. Complete the housing with a Coke can shell; a button on the outside triggers the syringe, causing the blaster to extend and fire in one motion — just like the MCU suit. The mechanism mirrors the same piston approach from the JT video, extended here to include a complete wrist-mount enclosure.
Which build are you trying first? Share your results, tips, or questions below.