Energy, Machines, and Motion
Part One: Energy
Lesson 4: Storing and Using Energy in a Battery
Students recharge batteries for different lengths of time to light a flashlight. Students measure how long the flashbulb light will stay lit, then record and graph their results. They use this data to make predictions for a new charging time
Focus Question: How does charging time affect the stored energy in a rechargeable battery?
3. Lesson Set-up and Management
EALR 2: Inquiry
Core Content: Questioning and Investigating
6-8 INQC Collecting, analyzing, and displaying data are essential aspects of all investigations.
6-8 INCD For an experiment to be valid, all (controlled) variables must be kept the same whenever possible, except for the manipulated (independent) variable being tested, and the responding (dependent) variable being measured and recorded. If a variable cannot be controlled, it must be reported and accounted for.
EALR 4: Physical Science
Core Content: Interactions of Energy and Matter
6-8 PS3A Energy exists in many forms: heat, light, chemical, electrical, motion of objects, and sound. Energy can be transformed from one form to another and transferred from one place to another.
- Students investigate how the energy stored in a battery depends on the amount of time the battery is charged.
- Students apply concepts of experimental design (prediction, collection of data, graphing, drawing conclusions).
- Students use evidence to make and test a prediction.
- Students draw conclusions based on evidence.
3. Lesson Set-Up and Management
Materials:
- Students need batteries that have been fully discharged in Lesson
4. Batteries from Lesson 3 should already be discharged so they should
be ready to go. Students need batteries that are fully charged in
Lesson 7, Lesson 8 and Lesson 9. You will need to devise a system for
managing batteries. Pictured is an example of how some teachers manage
uncharged and charged batteries. • Students place uncharged batteries
on the red paper, signaling to stop they are not ready. When the
batteries have been charged they are moved to the green paper
signaling they are ready to go.
- Check the timers ahead of time to make sure they are all working. Sometimes the timers are difficult for students to use, provide a small amount of time to practice using this tool.
- Students will need to average class data, consider having a chart
for students to record their trial results for the class to easily
view.
Student Management:
- Students keep track of time using a tool that will convert seconds to minutes. This may confuse some students. Review with students that 60 seconds is equivalent to one minute, 120 seconds is 2 minutes, and 240 seconds is 4 minutes.
- Inquiry Master 4.1 reviews how to correctly graph the data from
their investigation. Consider modeling the tips from this record sheet
on a poster. Students will be expected to graph data in many
investigations; this could serve as a model for future graphs in the
unit.
The graph students develop will be based
on class averages, not individual data.
- Spend time modeling with students how to correctly graph data. The reflection questions at the end of the lesson ask students to think about why they use class averages rather than personal data.
- You will have students go back to Lesson 2 and add to what they know about batteries.
- Prior to Lesson 5 you will want to collect a variety of objects with different masses and densities that students can weight with a spring scale. Try to get objects of similar size but with different densities.
- Prior to Lesson 7 you will need to recharge the D-cell batteries so they are fully charged.
Writing Support:
- In the Getting Started section of Lesson 4 students are asked to
predict how they think the charging time will affect the operation of
the light bulb. Consider using a format that contains "if, then,
because" in their predictions:
- If the batteries are charged for a longer period of time, then (what will happen). I think this because…
Reading Support:
- There are two readings after the lesson to support practical
applications for energy transformations, they include:
- Electric Cars: Back to the Future
- Putting the Wind to Work
Math Support:
- Students construct a graph using the averaged data from each group. Review with students that each group’s results constitutes one trial.
- Make sure your students use equal increments to represent time in their graph, on a few occasions some students only write in 60, 120, and 240 split equally apart, forgetting 180 seconds.
- Practice using timers converting seconds to minutes.