E_QUEST1 How does a faucet control when water turns on and off?
E_QUEST2 How does the base of an electric light bulb work?
E_QUEST3 What kind of bottle cap keeps a lid on tightest?
D_TEXTBLOCK_TEXT A screw is an <HL Topic=Incline.tpc>INCLINED PLANE</HL> that winds around in a spiral. It helps to <HL Topic=Work.tpc>WORK</HL> through each turn, and is a simple <HL Topic=Machine.tpc>MACHINE</HL>. <HL Topic=Friction.tpc>FRICTION</HL> helps keep the screw from turning backward or pulling out.
O_TEXTBLOCK_TEXT As this <HL Topic=Machine.tpc>MACHINE</HL> screw is made, you can see the metal wrapping around its shank. This forms an <HL Topic=Incline.tpc>INCLINED PLANE</HL> which will help do <HL Topic=Work.tpc>WORK</HL> each time the <HL Topic=Machine.tpc>MACHINE</HL> screw is turned.