Electromagnet Criteria Criteria Design 1 - iron nail, switch, 75 cm wire cut into 3 pieces, battery Design 2 - iron nail, 75 cm
wire, battery Design 3 - pencil, switch, 75 cm wire cut into 3 pieces, battery Design 4 - iron nail, light bulb, receptacle, switch, 75 cm wire cut into 3 pieces Pick up 10 staples Yes Yes No No Cost $3.15 $2.80 $3.15 $5.13 Switch on/off Yes No No No Electromagnets are used in junk yards and recycling plants to pick up and move certain metal objects. The more strength the electromagnet has, the greater the mass it can move. Mr. Garcia challenged his students to build an electromagnet. To simulate the mess of a recycling plant, the students were given 10 staples that their magnet had to pick up to be considered successful. Since an electromagnet requires electricity to control it, turn it on or off, the students had batteries to work with. Their job was to find the right design and orientation of the wire so that its magnetic field works just like a regular magnet, but you can turn it on and off, and it must be strong enough to pick up all 10 staples. Each group was given the following materials: 1 6-V Zn-C battery (US$1.30) 1 compass (diameter 16 mm; US$1.00) 1 75-cm length wire (US$1.50) 1 6.2 V, 0.5 A incandescent light bulb (US$1.30) 1 light bulb receptacle (US$1.98) 1 switch (US$0.35) 10 staples 1 iron/steel nail or other long cylindrical object 1 pencil or other long cylindrical wooden object The students set to work and ran the first trial of their electromagnets. The students data is compiled in the data table. Mr. Garcia told his students to evaluate their designs as if they were engineers. Design Team 4 had (1) the most expensive design and (2) it met none of the criteria. What modifications should Design Team 4 consider for the next trial? A) Use low cost materials. B) Add a battery and a switch. C) Replace the light bulb and holder with a battery. D) Use a battery, a switch, and a longer piece of wire.
