🚜 Trucks & Diggers!

What you’ll learn

1. Excavators: The Digging ArmLearn how an excavator's arm copies yours, how hydraulics move it, and why it rolls on tracks.An excavator digs with a jointed arm — boom, stick, and bucket — powered by hydraulic cylinders full of oil that does not squash. Tracks spread its weight. The house can spin while the tracks stay still, and the bucket can be swapped for tools like a breaker.
2. Dump Trucks and the GiantsUnderstand how a dump bed works and how big a Caterpillar 797F really is.A dump truck's bed is hinged at the back and lifted by a hydraulic ram. A Cat 797F can carry about 400 tons — about sixty African elephants — on six tires a little over 13 feet tall. The driver climbs a ladder to a cab with real blind spots.
3. Cranes: Lifting Without TippingLearn how counterweights, outriggers, and climbing frames keep cranes useful and upright.Cranes lift with a cable and hook. Counterweights balance the load like a seesaw. Mobile cranes plant outriggers so tires are not holding the lift. Tower cranes can top-climb: a hydraulic frame jacks the top up and a new mast piece slides in.
4. Pushers and SmoothersSee how dozers, graders, rollers, and loaders shape ground and build a road in order.Bulldozers push with a movable blade. Graders shave the dirt flat. Rollers pack it. Loaders scoop piles into trucks. A road is those jobs in order, then pavement.
5. The Truck With a Spinning DrumLearn what concrete is made of, why the drum turns, and that hardening is hydration, not drying.A mixer truck carries cement, sand, stone, and water. The drum turns so the mix does not settle or set. Concrete hardens by hydration and should be kept a little damp while it cures. Rebar takes the pulling that concrete cannot.
6. The Construction TeamSee that operators run every machine, that sites have safety gear for a reason, and that a building is an order of jobs.Every machine needs an operator. Hard hats and bright vests help people stay visible and protected. Watch from outside the fence, name what each machine is doing, and ask who chose today's order.

Questions this course answers

Grounded in trusted sources

• Caterpillar — 797F Mining Truck specifications (nominal payload 400 ton US / 363 t; tires 59/80R63; loading height empty 23 ft / 6,998 mm; front canopy height empty 25.33 ft)
• Finning — '5 Facts You Might Not Know About the 797' (tire a little over 13 ft in diameter; six tires)
• WWF — African elephant (about 6 tons) — used only to turn 363 metric tons of payload into a kid comparison of about sixty elephants
• Portland Cement Association — cement.org, Applications of Cement (portland cement hardens by hydration with water; curing keeps moisture available so concrete keeps gaining strength)
• WorkSafeBC — Hazard Alert WS 2021-02, 'Top climbing a tower crane' (hydraulic ram and climbing frame add mast sections as the crane grows)
• OSHA — 29 CFR 1926.100(a) (protective helmets where there is possible danger of head injury from impact or falling objects)
• OSHA — 29 CFR 1926.651(d) (warning vests or other high-visibility garments when workers are exposed to public vehicular traffic)

Every Wunder lesson is built from real, reputable sources — never invented.

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