Can You Get Two Light Bulbs to
Light?
Using 2 bulbs, 4 wires, 2 batteries, and 2 doohickeys (light bulb
holders), can you get 2 light bulbs to light?
Think about what you know about circuits when doing this
investigation. Make a prediction about how you think you can
do this. Try it out to see if it works, and record the combinations
you try. When you are successful, make a labeled drawing of
your successful combination. Draw some conclusions about
what you learned, what worked and what did not work, and how
a circuit works. You will then demonstrate your combination to
the class.
Can You Get Two Light Bulbs to Light?
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Can You Get Two Light Bulbs to Light?
Suggested Grade Span
3–5
Task
Using 2 bulbs, 4 wires, 2 batteries, and 2 doohickeys (light bulb holders), can you get 2 light
bulbs to light?
Think about what you know about circuits when doing this investigation. Make a prediction
about how you think you can do this. Try it out to see if it works, and record the combinations
you try. When you are successful, make a labeled drawing of your successful combination.
Draw some conclusions about what you learned, what worked and what did not work, and how
a circuit works. You will then demonstrate your combination to the class.
Big Ideas and Unifying Concepts
Cause and effect
Models
Physical Science Concept
Transfer and transformation of energy
Mathematics Concepts
Data collection, organization and analysis
Diagrams
Time Required for the Task
Approximately two 45-minute sessions.
Context
This task is used to assess students’ understanding of circuits. We previously lit one light bulb
using one bulb, one battery and two wires. We discussed what a circuit is and how it works.
Students will apply this knowledge to the more complex problem of lighting two bulbs. Students
will also practice the scientific method during this investigation.
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What the Task Accomplishes
This task allows the teacher to assess the students’ understanding of electrical circuits and see
how well they use science process skills – such as drawing conclusions based on data.
Students will make predictions using prior knowledge about circuits and then test their ideas.
Students will draw a detailed and labeled picture of their circuit and then draw conclusions
about what they learned from this investigation. As a whole class, each student group will
demonstrate its circuit in order to see the many different combinations that can be made. This is
important for students to understand: There is not just one solution.
How the Student Will Investigate
Before beginning this task, we reviewed what a circuit is and how students made one to light
one bulb. Students were then given the materials. First, the students made predictions about
how to get two bulbs to light. Next, they tested their ideas and recorded the combinations they
tried. When they found a combination that worked, they made a detailed and labeled picture of
it and then drew conclusions about what they learned, using appropriate vocabulary that
demonstrated their understanding of circuits. Finally, they demonstrated and explained their
circuit to the class.
Interdisciplinary Links and Extensions
Science
Students often want to try to light more bulbs. I always allow time for this, as it leads nicely into
an investigation of series and parallel circuits. We also look at open and closed circuits, as well
as at conductors and insulators. The students usually conclude this unit by making circuit
boards in which they write questions from any topic and the correct answer lights up. This year,
I have also decided to include some design technology into this unit by asking students to
create something that uses a circuit (to light a bulb). They could design a reading light, a game,
etc.
Social Studies/Language Arts
Students can research electricity, how it was discovered, and how it has impacted our lives. An
interesting way to present the factual information might be to create a family album for Thomas
Edison, complete with the important events of his life. Illustrations can be drawn or cut from
magazines. Research can be presented to the class.
Real-World Connections
Students can investigate how they use electricity in their lives. They can also look at ways to
conserve electricity in their homes. Guest speakers from local electric plants might come in to
discuss conservation measures and sources of electricity. Students can plan a conservation
day at school to make others aware. Students can keep logs of their daily use of electricity at
home and in school.
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Teaching Tips and Guiding Questions
It is important to make sure that students have a good understanding of circuits before
beginning this task or they might become frustrated. They also need to have had experience
exploring with the materials. To help guide students’ thinking, here are some questions you
could ask:
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What do you know about circuits that can help you light two bulbs?
What do you think might work? Why? Is it a circuit? How can you tell?
What do you think would happen if you tried this?
Why do you think this combination isn’t working?
How does a using a circuit help you to do this? Can you follow the path?
What did you learn about circuits during this investigation?
Did anything surprise you?
Concepts to be Assessed
(Unifying concepts/big ideas and science concepts to be assessed using the Exemplars
Science Rubric under the criterion: Science Concepts and Related Content)
Physical Science – Transfer and Transformation of Energy: Students understand that energy
is a property of many substances, that it is associated with electricity and that it is transferred in
many ways. Students can explain that electrical current moves through a circuit in a continuous
path unless interrupted and that a circuit is a continuous path connecting bulb, wire and battery,
providing a means of transferring electrical energy.
Scientific Method: Students observe and explain reactions when variables are controlled
(cause and effect).
Mathematics: Students use diagrams and collect, organize and analyze data appropriately.
Skills to be Developed
(Science process skills to be assessed using the Exemplars Science Rubric under the criteria:
Scientific Procedures and Reasoning Strategies, and Scientific Communication Using Data)
Scientific Method: Predicting, drawing and labeling, testing ideas, recording data, making
observations, drawing conclusions, manipulating tools, communicating findings, challenging
misconceptions and raising new questions.
Other Science Standards and Concepts Addressed
Scientific Method: Students describe, predict, investigate and explain phenomena.
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Scientific Theory: Students look for evidence that explains why things happen and modify
explanations when new observations are made.
Suggested Materials
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D-cell batteries (enough for each group to have two)
Thin insulated wire with copper ends exposed
Flashlight bulbs
Light bulb holders (You can also use old Christmas tree light strings – they are colorful and
you do not need the holders. You will need to cut these so that there is about three inches
of wire on either side of each bulb.)
Possible Solutions
Students will find several different ways to make a circuit that works. They do not have to use
all the materials provided, except that they do have to light two bulbs. A good solution will
include a prediction, labeled drawings of what they tried, what worked, and conclusions that
reflect their understanding of the concepts. Some appropriate science terms should be included
in the explanation: circuit, electricity, electrical energy, pathway, light bulbs, battery, wires,
doohickey, etc.
Task-Specific Assessment Notes
Novice
This student includes a prediction of what might work and a labeled drawing of what did work.
The student indicates that what s/he tried first did work. The drawings are a little unclear (for
example, there might an extra wire in the first drawing and three bulbs attached in the second
drawing). Conclusions do not include any vocabulary or any discussion of how the student's
circuit worked and why. There is no clear evidence (except for the drawings), that the student
understands the concept of what a circuit is.
Apprentice
This student includes labeled drawings of what was tried but does not indicate either as a
prediction. Drawings do indicate what was tried before being successful. The student's drawing
of what did work clearly shows a circuit, although the conclusion is not as detailed as it could
be. The student indicates some understanding of what a circuit is (discussing how the electricity
flows to reach the bulb) and that it is a circuit because of its shape (although it isn’t always a
perfect circle). The conclusion could be clearer and could include more in-depth information
about the concepts.
Practitioner
This student includes a prediction and clearly labeled and detailed drawings of what s/he tried
and what worked. The combination was interesting in that s/he put the battery on the bulb
holder as well as the bulbs. The student's explanation and conclusions include appropriate
vocabulary, a description of the process in which electricity travels, and that there should be no
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gaps. This reflects good understanding of the concepts and process, in that the student
identifies both the source of energy and the pathway it travels.
Expert
This student includes a prediction as well as some trial ideas. These are labeled, as is the
drawing of the complete circuit that worked. Instead of labeling the specific drawing, the student
uses a key that helps to communicate his/her learning. The drawing of the complete circuit is
very clear, even without the key. Explanations and conclusions include appropriate vocabulary
and demonstrate an excellent understanding of the concepts. The student also extends his/her
thinking to predict how to make three light bulbs light – demonstrating use of prior knowledge
and conceptual understanding.
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Novice
Can You Get Two Light Bulbs to Light?
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Novice
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Apprentice
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Practitioner
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Expert
Can You Get Two Light Bulbs to Light?
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Expert
Can You Get Two Light Bulbs to Light?
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