Metal, Heat and Pressure: teacher key

How Cars Are Made, grade 9 edition, written for 9th grade. How presses, hydroforming, die casting and welding turn flat metal into a car body, and what each method gains and costs.

Read the book. Print this page for the key.

Questions and answers

1. What does hydroforming use to press metal into a die?
   • A rope and winch
   • High-pressure hydraulic fluid (answer)
   • Molten aluminum
2. Which is a trade-off of big castings?
   • They need no tooling
   • They use more parts
   • Voids can form inside (answer)
3. What is body in white?
   • The stage when the frame has been joined, before painting (answer)
   • A white primer coat
   • A kind of robot
4. How does spot welding melt the metal?
   • A flame
   • Electrodes concentrate a large current into a small spot (answer)
   • Hydraulic fluid
5. Why is a big cast part hard to do well?
   • It needs no tooling
   • It always has 70 parts
   • A single flaw can ruin the whole piece (answer)

Words

• hydroforming: fluid-pressure shaping
• stamping: pressing metal
• voids: empty pockets
• unibody: one-piece body
• electrodes: current carriers