Download Student Exploration Sheet: Growing Plants

SNC1DI
Name: __________________
Date: __________________
Ohm’s Law Gizmo
Go to www.explorelearning.com and click on “Enroll in a Class” (blue button), and enter class code:
SNC1DI-01: 4WXDWMVZPB
SNC1DI-02: QBMZUVA3YC
Click on continue and follow directions to “Register now to enroll”. Write down your username and password:
Username: ________________________

Password: ______________________
You will see a Gizmo called “Circuits” on our class page. Click on “Launch Gizmo”.
NOTE: a yellow bar will appear across the top of your screen. Click on “Run this time”.
Gizmo Warm-up
Drag and drop components onto the circuit board to create a circuit with a battery, a light
switch, a wire, and a light bulb, as shown. Turn on show current and select electron flow. The
moving dots represent a current of electrons—tiny, negatively charged particles—moving
through the wire.
Under “Selected battery voltage”, drag the slider all the way to the left (so voltage is 1 V), and then drag the slider slowly
to the right to increase the battery’s voltage.
A. How does increasing the battery’s voltage affect the current?
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B. How does changing the battery’s voltage affect the brightness of the light?
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Lab Activity: Ohm’s Law
Introduction: Resistors are devices that slow the flow of current in a wire. The resistance is measured in ohms.
Question: What is the relationship between voltage, current, and resistance?
Hypothesis:
 If the resistance in the circuit is increased, then current will ______________________.
Procedure and Observations:
1. Create the circuit shown at right. (Be sure to use the 10 ohm resistor.)
 Draw a circuit diagram of the circuit you have built using the proper symbols.
(For this diagram, draw a 2-cell battery).
2. Click on the battery. Set the Selected battery voltage to 10 volts.
3. Turn the light switch On to start the flow of current.
4. Drag the Ammeter ( ) to various parts of the circuit. The ammeter’s measurements can be seen in the box on the
left hand side of the screen called “Meters” beside the word “Ammeter”.
 Is the current the same throughout the circuit, or does it change?
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5. Use the Ammeter to measure the current in the circuit when the voltage of the battery is set to 10 volts, 20 volts and
30 volts.
 Complete Table 1 below to show the current in the circuit as the voltage is increased.
Table 1: Voltage and current with 10 ohm resistor
Current (A)
Table 2: Voltage and current with a 20 ohm resistor
Current (A)
Voltage (V)
Voltage (V)
10
10
20
20
30
30
6. Change the 10 ohm resistor in your circuit to a 20 ohm resistor and record the current in Table 2 of step 5 above.
Analysis:
1. What is the mathematical relationship between voltage (V), resistance (R), and current (I)? Express your answer as an
equation. This equation is known as Ohm’s law.
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2. Using Excel, make a graph of voltage vs. current (your graph should have 2 lines, one for the 10 ohm resistor and
one for the 20 ohm resistor). Use the graphing handout to help you make your graph. Print your completed graph.
a. Find the slope of each line from the equation of the trendline.
Slope of 10 ohm resistor: ___________________
Slope of 20 ohm resistor: ___________________
b. How does the slope of the line relate to the resistance of the resistor?
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c. Use your graph to find the current through each resistor if the voltage was 12 V. Use dotted lines and a ruler to
show how you used your graph to determine the current for each resistor.
Current for 10 Ω resistor: _________________
Current for 20 Ω resistor: ____________
Check your answer using the Gizmo.
3. Use Ohm’s law to find the resistance of the light bulb in the Gizmo.
Include the following in your answer:
 Draw a diagram of the circuit you built
 Record all necessary data
 Show the calculations needed to determine the resistance.
4. Challenge! Do this only if you have extra time. Use the Gizmo to design a circuit where one battery powers two
light bulbs, and each light bulb can be controlled by its own switch. Draw a circuit diagram showing your design.
5. Homework: Complete this Gizmo and answer questions from textbook on p. 319 # 1, 2a, 4, 5, 6, 7. The Gizmo will be
collected next class. The homework will be checked but not collected.