The following are the pin outs for the 555 Timer IC (source: http://www.markallen.com/teaching/ucsd/147a/lectures/lecture4/5.php): Pin 1 is ground. It is connected to the negative side of your battery or ...
1 Base Grid (11” x 7.7”) # 6SC BG
1 Eight-Pin IC Socket # 6SC ?U8
1 0.02uF Capacitor # 6SC C1
1 Variable Resistor #6SC RV
1 Whistle Chip # 6SC WC
1 9 Volt Battery Holder # 6SC B5
4 Single Snap Conductor # 6SC 01
7 Conductor with 2-snaps # 6SC 02
2 Conductor with 3-snaps # 6SC 03
3 Conductor with 4-snaps # 6SC 04
Build the circuit shown in the photographs.
When you move the slider on the Variable Resistor (RV) this changes the resistance of the circuit. Since the Variable resistor is connected to pin 7 changing the resistance controls the timing of how often the 0.02uf capacitor (C1) charges and discharges. When you change the resistance in the circuit, you change the pitch of the the square wave tone you hear on the speaker.