I began creating my first circuit by attaching the 9v battery to the connector, plugging it into the power supply, and connecting the power supply into the breadboard. Next, I made sure that the plastic pieces on either side of the power supply were set to 5v, and placed one jumper cable connecting the positive-charged left column into A15 on the breadboard. I then added a red LED to row 15, placing the anode toward the jumper cable in E15, and the cathode in H15. Lastly, I inserted a 220 Ohm resistor next to the LED, with one wire in J15 and the other wire in the ground column on the right side of the breadboard. I tested my circuit by turning on the switch on the power supply and making sure the LED turned on. 

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I created the LDR Circuit by following the same process as the first circuit described above, but with a light-dependent resistor (LDR) in the place of the 220 Ohm resistor. I tested this circuit by turning on the power supply, and covering the sensor with my finger to see if the brightness of the LED would change with the amount of Light shone on the LDR. When the LDR was covered, the LED would get dim. When a light was shone on the LDR, the LED would get bright. This caused me to reason that more light allows the LDR to have less resistance, allowing more charge flow through the circuit, and causing the LED to be brighter.