DIY Flashlight

Spark new insights about electrical engineering!

About the Activity

Electricity keeps the world going. In this electrifying activity, kids will learn about electrical energy using batteries and conductors as they create a battery-powered flashlight with an on/off switch.

 

Grades: 4-7
Topic: Electrical Engineering
Estimated Time: 1 Hour

 

Brought to you by HughesNet and University of Florida Extension

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Supplies
These simple materials will get you started.

  • Small piece of cardboard
  • Two large brass fasteners
  • Red and blue copper wire
  • 1.8W lightbulb
  • 2 D cell batteries
  • Electrical tape
  • Scissors
  • Wire strippers
  • Paper cup
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Activity Steps
Follow these simple steps to create your flashlight.

Before you start the activity, think about the amazing ways that electrical currents work. For electricity to work, flowing electrons—tiny particles that carry electricity—must make a complete path, returning to where it started. That path is called a circuit. What does the word circuit mean? The word circuit comes from the word circle: So the electrons must travel in a circle to keep flowing.

 

  1. To begin the activity, take a piece of cardboard and trace a circle using the end of the opening cardboard paper towel roll. Cut this circle out.

 

  1. Cut a small hole in the center of the cardboard circle and carefully place the lightbulb through it.
  2. Then take the cardboard paper towel roll and cut it lengthwise.
  3. Using two brass fasteners, insert the first fastener inside the seam you just cut, approximately 2 inches below the top edge of the cardboard. Then, place the paperclip around it and insert the second brass fastener close enough for the paperclip to reach it. Did You Know? When you touched the metal paperclip to both fasteners, this created a closed circuit to act as a switch.
  4. Next, take two pieces of individual copper wires and strip them so that approximately two inches of copper is exposed on both ends. Use different colors or label them ‘red’ and ‘blue.'Did You Know? Copper and brass are both good conductors. This means that these metals easily transmit the flow of electricity from the energy source - a battery in this case.
  5. Wrap the red wire around the first brass fastener and the blue wire around the second, and fold the fasteners over to secure the wire.
  6. Place the two D cell batteries on top of each other with the opposite terminals touching and secure them together tightly with electrical tape (see image C for reference).How Does It Work? When you taped the batteries together and attached the wires to the negative terminal and to the metal base of the lightbulb, you created a closed circuit that allowed energy to flow from the batteries into the lightbulb and light it. The brass fasteners act as conductors of electricity.
  7. Take the lightbulb in the cardboard circle and place it at the opening of the cardboard roll.
  8. Lay the batteries flat on top of the brass fasteners and secure them in place with duct tape. Make sure the positive battery terminal makes contact with the metal tip of the lightbulb.Did You Know? Batteries are a way to store electrical energy. In order to access that energy, you need to create a circuit using the battery’s direct current.
  9. Wrap the exposed red wire on the first fastener around the metal base of the lightbulb and secure it with electrical tape.
  10. Now, it’s time to turn your flashlight on! Take the exposed blue wire connected to the second brass fastener and secure it to the bottom of the second battery using electrical tape. Once you connect the paperclip to the second fastener, the lightbulb should light up! To turn the lightbulb off, simply disconnect the paperclip.It Worked! That’s because you created what is called a closed electrical circuit, which simply means that the circuit was completed, letting those electrons flow back to where they started. An electric circuit is considered open if the electrical path is broken and electrons are not allowed to flow to complete the cycle – so, if your light didn’t light up, it’s probably because the circuit was still open.
  11. Roll the cardboard roll together and secure using electrical tape. Flatten and cut the bottom off the paper cup to fit around the top to focus the light from the lightbulb. Secure using electrical tape.How Does It Work? The paper cup helps to illuminate the lightbulb by diffusing the light it emits.
making a flashlight at home

Reflection Questions

Questions for your kids and teens.

  1. Why do the wires need to be stripped to make the lightbulb light up?
  2. Why do the batteries need to touch the brass fasteners?
  3. Is the circuit “open” or “closed when the paperclip touches both brass fasteners and the light is on?
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Investigate and Explore

The next time you hold a flashlight, see if you can identify the difference between it and your DIY flashlight. Can you explain how it works to a friend or parent?

 

Electrical currents are everywhere. They power our screens, our transportation, and even our food preparation. Consider this: Currents and electricity support the lives of the more than 300 million people living in the United States. And 450,000 miles of power lines across the country make that possible. If this activity interested you, you may have a career ahead of you in electrical engineering.

4h-simple-circuit-illustration

Career Connections

4-H youth explores electrical engineering in rural areas
Rural STEM Careers

As it turns out, STEM careers aren’t just in cities. If you live in a rural community, you probably know the farming and agriculture jobs available to you. But did you know that STEM careers exist no matter where you live? It’s true: Science- and tech-centric careers don’t just happen in urban areas.

 

Check out our interview with Martin Nelkie, an electrical engineer in South Dakota to learn more about rural STEM careers.

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