Topic: Physical Sciences - Energy
Software: Franklin’s Lab
Investigation - Resisting the Flow
Lesson Overview
Activity video available at edu.zspace.com
Students will explore how changing the resistors can “slow down” the flow of
current. Students will discover that each type of LED has a specific current and
voltage requirements. They will use this knowledge to change the brightness of
an LED.
Grade level: 3rd - 5th
Lesson Time: 45 Minutes
Key Terms:
Breadboard
Circuit
Closed Circuit
Objectives
Components
○○ Determine the requirements to light an LED
Conductivity
○○ Evaluate the purpose of resistors in the electrical current of a circuit
Current
Electricity
Standards (NGSS and Common Core)
LED
For state specific standards visit edu.zspace.com
Open Circuit
Voltage
Next Generation Science Standards
Resources:
Answer Key
○○ Physical Science - Energy
• 4-PS3-2 Make observations to provide evidence that energy can be transferred
from place to place by sound, light, heat, and electric current.
Common Core Connections
○○ Language Arts
• W.4.7 Conduct short research projects that build knowledge through investigation of different aspects
of a topic.
• W.4.8 Recall relevant information from experiences or gather relevant information from print and
digital sources; take notes and categorize information, and provide a list of sources.
Differentiation (Δ)
○○ Group students heterogeneously to allow students with a strong command of the English language to
assist in reading or interpreting questions
○○ Provide paper copies of diagrams to students to use as a reference
○○ Provide a handout with a list of vocabulary terms and definitions that will appear in the activity
○○ Allow students to provide answers that are handwritten, typed, or verbal
○○ Enrichment: Students could change an additional variable listed in activity and look for patterns
○○ Enrichment: Students could find real-world problems involving the concept and design solutions to
those problems
○○ Specific differentiations are indicated in this document with a Δ symbol
Investigation - Resisting the Flow
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Topic: Physical Sciences - Energy
Software: Franklin’s Lab
Introduction
Students need a basic knowledge of circuits and electrical current before beginning this activity. The
teacher will explain to students that they are going to learn how to light an LED. An LED has specific
current and voltage requirements. Students will investigate how resistors change the current flow.
Students will look for changes in brightness of the LED as they change the resistance.
Activity
1. Complete the circuit below by adding a blue LED and a 100 ohm resistor.
2. Observe the circuit. Did the LED light up? What direction is the current flowing?
3. Changing only the type of resistor, create a second circuit with a dimmer blue LED. Be careful that
the LED does not turn off. What size resistor did you use to successfully complete this circuit? Take a
screenshot of your circuit.
4. Using one of the circuits on your breadboard as a "test,” determine the minimum amount of resistance
to blow the LED. What ohm resistor did you use?
5. Using what you discovered in this investigation, what could you conclude about the relationship
between resistance and LED brightness?
6. Put all the inventory items currently on your breadboard into the trash so you have an empty
breadboard.
7. Extend your learning: Now, attempt to create three different circuits on your breadboard, using
9V batteries and red LEDs in place of blue. The LED in each circuit should have a different level of
brightness. Take a screenshot of your three circuits when they are complete.
8. What ohm resistors did you use to complete this task? (Specify which resistor was used for which level
of brightness!)
Δ Students can light a red LED with a series battery.
Teacher Note: The reference guide for Franklin’s Lab provides a chart for lighting the
different LEDs.
Closing
After the students complete the activity, they will discuss their observations, challenges, and
successes. Students will discuss the role of resistors in a circuit. Students will complete the following
questions.
Investigation - Resisting the Flow
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Topic: Physical Sciences - Energy
Software: Franklin’s Lab
Questions for Discussion
1. How do you know that energy (electricity, in this case) was being transferred?
Answers will vary. Sample Answer: I know that energy was being transferred because the electricity
went from the battery pack into the LED to turn it on.
2. What are some advantages of having the red and blue LEDs light up with different current and voltage
requirements?
Answers will vary. Sample Answer: I could change the resistance and only one of the lights goes on.
3. If you had used ten 100-Ohm resistors on one circuit, and 1 kilo-Ohm (1,000 Ohms) resistor on the
other circuit, how would you expect the current of electricity to compare between the two circuits?
Explain your answer.
Answers will vary. Sample Answer: I would expect the current of electricity to be exactly the same in
each circuit. Ten 100-Ohm resistors would make a total of 1,000 Ohms of resistance, which is the same
as 1 kilo-Ohm (kΩ).
Δ Investigate Further
Follow-up Activity: Complete the "Challenge - Resisting the Flow" activity.
Investigation - Resisting the Flow
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Topic: Physical Sciences - Energy
Software: Franklin’s Lab
Answer Key
Activity Questions Provided in Franklin’s Lab
1. Complete the circuit below by adding a blue LED and a 100 ohm resistor.
2. Observe the circuit. Did the LED light up? What direction is the current flowing?
Answers will vary. Sample Answer: Yes the it did light up. The current is flowing clockwise.
3. Changing only the type of resistor, create a second circuit with a dimmer blue LED. Be careful that
the LED does not turn off. What size resistor did you use to successfully complete this circuit? Take a
screenshot of your circuit.
Answers will vary. Sample Answer: I used a 220 ohm resistor. There is also a screenshot.
4. Using one of the circuits on your breadboard as a "test,” determine the minimum amount of resistance
to blow the LED. What ohm resistor did you use?
Answers will vary. Sample Answer: I need 47 ohms to blow the blue LED.
5. Using what you discovered in this investigation, what could you conclude about the relationship
between resistance and LED brightness?
Answers will vary. Sample Answer: The less resistance the brighter the LED. However, if there is too
little resistance then the LED will blow.
6. Put all the inventory items currently on your breadboard into the trash so you have an empty
breadboard.
7. Extend your learning: Now, attempt to create three different circuits on your breadboard, using
9V batteries and red LEDs in place of blue. The LED in each circuit should have a different level of
brightness. Take a screenshot of your three circuits when they are complete.
8. What ohm resistors did you use to complete this task? (Specify which resistor was used for which level
of brightness!)
Answers will vary. Sample Answer: The red LED was off at 200 ohms, lit at 100 ohms, bright at 11 ohms.
Investigation - Resisting the Flow
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