Parallel and Series Lab Inquiry with Solar Panels

Purpose: To discover the differences between connecting solar panels in parallel and series by measuring voltages and current and using a water pump to do work.

Hypothesis: Because a ______circuit creates ______

(parallel/series) (more current/more voltage)

it should allow the pump to do work faster (have more ______).

Materials: See Setting Up on page 1 in the solar kit box to check all is there. For this experiment you need:

·  2 solar panels

·  wires with clips

·  water pump

·  multimeter

·  two large containers (one with water)

·  switch

·  stopwatch

·  graduated cylinder

Methods:

Part 1: Measuring V and I alone and in parallel and Series Circuit

1)  Follow directions on page 2 “measure the Voltage and Current for One Panel) to determine the voltage and current. Record in table.

2)  Predict the total voltage and current for TWO panels connected in series and in parallel. Record in table.

3)  Follow direction on page 3 “Connecting Two Panels in Series.” Measure and record readings in table.

4)  Follow direction on page 4 “Connecting Two Panels in Parallel.” Measure and record readings in table.

Circuit / Predicted I (A) / Predicted V (V) / Actual I (A) / Actual V
(V)
Single Panel
Series
Parallel

Question 1: Were your predictions correct? Why or why not?

Question 2: Using what you know about parallel and series circuits, why did you get the readings you did?

Question 3: Which set up will allow the water pump to do the most work in the least amount of time? Why?

Part 2: Determining the power given to a water pump.

1)  Using ONE panel and a switch in SERIES, connect your panel to the water pump. Make sure the switch is OPENED while connecting wires. See page 6 for some help with connections but use only ONE panel.

2)  Place pump in bucket of water so it is submerged but free wires are in the air.

3)  Place the other end of the pump in an empty bucket.

4)  Close the switch and start your stopwatch. Allow the pump run for 30 seconds.

5)  Measure and record the volume of water collected.

6)  Repeat for THREE trials.

7)  Repeat for TWO panels connected in series.

8)  Repeat for TWO panels connected in parallel.

Circuit / Trial / Volume of water in 30s
Single / 1
2
3
Avg
Series / 1
2
3
Avg
Parallel / 1
2
3
Avg

Question 4: Which set up had the most power? How did you know?

Question 5: Which set ups had the same power? How do you know?

Question 6: Which measurement, voltage or current, was directly proportional to power? Why?