1. TESLA Variables Unit: FOSS KIT
Pendulums
TESLA Variables Unit: FOSS KIT 1

2. A system is a set of related objects that can be studied in isolation.
INTENDED CURRICULUM FOR TODAY’S LESSON
The Big Idea…
A system is a set of related objects that can be studied in isolation.
In a controlled investigation, only one variable can be changed, and the results can be compared to a standard. 2

3. ENGAGING SCENARIO
TESLA Engineering is a very busy company. They help other companies solve design problems by conducting tests with models. The engineers use information they receive from testing the models to give advice to other companies so they can build a better product. Some things are small like clocks. Other things are large like boats and airplanes. TESLA Engineering is so busy right now that they cannot get all of their testing done for other companies. They need your help. They need to do some testing for Clock Works, a clock manufacturing company. Clock Works is making a new clock that has a pendulum going back and forth. The pendulum on the clock must have a certain number of cycles each minute. They are not sure how to make one that will keep accurate time. TESLA Engineering has sent us some model building tools and some printed materials that may help us with the tests. They need this information in about two weeks.
What is the problem we need to solve?
What do we need to investigate? 3

4. Focus Question (What is the problem?)
Discuss ideas with a partner for a possible focus question. Your focus question should be connected to what the scenario wants us to do…
How can we…
How can we make a clock with a pendulum that would keep accurate time?
NOTEBOOK ENTRY 4

5. New Vocabulary Pendulum Anchor Point Cycle: String Cycle Mass
Any mass suspended on a rope, string, or arm that is free to pivot from an anchor point
Anchor Point
Cycle:
One complete swing back and forth of a pendulum
String
Cycle
Mass
NOTEBOOK ENTRY 5

6. Previous Knowledge Prediction (related to the focus question)
Share experiences with pendulums
Prediction (related to the focus question)
Discuss your ideas with a partner, then write a prediction in your notebook and be ready to share.
I can use a pendulum to keep accurate time by _____.
I think that a pendulum will need ____ cycles every ____ to keep accurate time because_________.
NOTEBOOK ENTRY 6

7. The TESLA engineers sent us some materials to construct a standard pendulum model.
or washer
pendulum
pendulum
or washer

8. Testing the Standard Pendulum
In order to standardize the anchor point for the pendulums, tape a pencil securely to a desk or table so that the blunt end of the pencil sticks over the edge of the table a few cm. Then hang the pendulum loop over the pencil (anchor point).
How many cycles can your pendulum make in 15 seconds?
How can we find out?
I will be the timer and you will be the counters. I will say go and you will count silently to yourself until I say STOP.
# of Cycles in 15 seconds
Trial #1
Trial #2
Trial #3
Trial #4
Average
NOTEBOOK ENTRY

9. Designing and Experiment
What could you change in your pendulum system that might change the number of cycles in 15 seconds?
String Length
Angle of Release
Mass
NOTEBOOK ENTRY

10. Designing an Experiment
A variable is anything that you can change in an experiment that might affect the outcome.
mass (number of washers)
release point (hold the mass higher or lower)
length of string (longer or shorter)
You are going to conduct an experiment.
An experiment is an investigation designed to find out how variables affect outcomes.
This will also be a very special type of experiment called a controlled experiment. In a controlled experiment, we only change one variable at a time.

11. Designing an Experiment
Variable: What are we going to change?
Control: What are we going to keep the same?
Mass (Weight)
Angle of Release: 0* String Length: 38cm Time: 15 seconds
Angle of Release
Mass: 1 washer
String Length: 38cm Time: 15 seconds
String Length
Angle of Release: 0* Mass: 1 washer
Time: 15 seconds
NOTEBOOK ENTRY

12. Collecting Data
Let’s start with the angle of release. We are going to use a protractor to measure the angle from which we release our pendulums: 0*, 20*, 40* and 60* angles from the desk top.
Desk Top 0*
20*
40*
60*
Will the angle of release change the # of cycles in 15 seconds? Why…
NOTEBOOK ENTRY 12

13. Variable: Angle of Release
Collecting Data
Will the angle of release change the # of cycles in 15 seconds? Why…
NOTEBOOK ENTRY
Variable: Angle of Release
# of cycles in 15 Seconds
Trial 0*
20*
40*
60* #1 #2 #3
What does your data conclude about changing the angle at which the pendulum is released?

14. Collecting Data
Let’s now find out if changing the mass (washer) will change the number of cycles in 15 seconds. (add more washers or objects)
NOTEBOOK ENTRY
How do you think adding mass will affect the number of cycles?
Where will the release point be if this is our standard pendulum system and we are testing for the variable of mass?
Release point should be standard 0* even with desk top
Mass can be a series of pennies added to increase weight or different objects added. Caution… Larger objects can increase the overall length of the pendulum.
Variable: Mass
# of cycles in 15 Seconds
Trial
1 Washer
_____ #1 #2 #3
What does your data conclude about changing the mass of the pendulum? 14

15. Collecting Data
We are now going to make new pendulums to determine if length is a variable that will affect the number of cycles.
NOTEBOOK ENTRY
How do you think changing the length of the pendulum will affect the number of cycles?
Pendulum Lengths: 13 cm, 15, cm, 17 cm, 18, cm, 20 cm, 22 cm, 25 cm, 29 cm, 33 cm, 45 cm, 55 cm, 70 cm, 90 cm
Since this is a controlled experiment we will use a mass of one penny and a 0* angle of release. 15

16. Variable: Length of Pendulum
Collecting Data
Variable: Length of Pendulum
# of Cycles in 15 Seconds
Length
Trial #1
Trial #2
Trial #3
13cm
15cm
17cm
18cm
20cm
22cm
25cm
29cm
33cm
38cm
45cm
55cm
70cm
90cm
NOTEBOOK ENTRY
What does your data conclude about changing the mass of the pendulum?
Depending on time constraints you may want to assign each group 2-3 different pendulums to collect data for the class 16

17. Interpreting Data
Number of Cycles in 15 Seconds
Scientists will often graph data to help them interpret the results of their investigation.
Concrete Graphs
- Show and display a relationship using actual materials
Use your data table to make a concrete graph
A 38cm pendulum completes 12 cycles in 15 seconds
Hanging actual pendulums based on the number of cycles they completed will show if there is a pattern or relationship when length changes
Make a strip of cycles to display on your wall. You can punch holes with a hole punch and use paper clips as hooks for each number
NOTEBOOK ENTRY

18. Interpreting Data
Number of Cycles in 15 Seconds
Scientists will often graph data to help them interpret the results of their investigation.
Picture Graphs
display relationships between two variables.
Use your data table to make a picture graph using the template the engineers gave us.
A 38cm pendulum completes 12 cycles in 15 seconds
Length of Pendulum (cm)
NOTEBOOK ENTRY

19. Interpreting Data two-coordinate graph.
A two-coordinate graph shows a series of experiments when a variable is changed by steps.
Use your data table to make a two-coordinate graph using the template the engineers gave us.
NOTEBOOK ENTRY
Number of Cycles in 15 Seconds
A 38cm pendulum completes 12 cycles in 15 seconds
Y-axis: Dependent Variable
The number of cycles depends on the length of the pendulum
X-axis: Independent Variable
Length of Pendulum (cm)

20. Interpreting Data
We have now interpreted our data in at least 4 different ways:
A table with the data we collected for each trial
A concreted graph using actual materials
A picture graph with the drawing of the real objects
A two-coordinate graph which used data to symbolize the real objects
How are the 4 ways we can display data different?
How are they the same?
Why is a picture graph useful?
What is a benefit of using a two-coordinate graph?
Could you use your data to predict the number of cycles a pendulum will complete for a length we did not test?
NOTEBOOK ENTRY 20

21. Interpreting Data
Using the graphs you created as evidence, is there a relationship between the length of the pendulum and the number of cycles in 15 seconds?
Complete the sentences orally. Then record them in your scientist notebook.
The longer the pendulum, the ____ the cycles.
The shorter the pendulum, the ____ the cycles.
The greater number of cycles, the ___ the pendulum.
The fewer number of cycles, the ____ the pendulum.
NOTEBOOK ENTRY 21

22. MAKING MEANING CONFERENCE
Listen and discuss
SHARE DATA COLLECTED 22

23. MAKING MEANING CONFERENCE
What is a pendulum?
What is a variable?
What variables did you test to determine if they would affect the number of cycles the pendulum makes in 15 seconds?
Which variable affected the number of cycles the pendulum makes in 15 seconds? How?
How do scientists use graphs to make predictions?
Which pendulum design could be used to keep accurate time? 23

24. Claims and Evidence
How can we make a clock with a pendulum that would keep accurate time?
I claim that…
I claim this because…
Mass does not change the number of cycles a standard pendulum makes in 15 seconds
Angle of release does not change the number of cycles a standard pendulum makes in 15 seconds
Length of the pendulum is the only variable that changed the number of cycles a pendulum makes in 15 seconds
The longer the pendulum the fewer cycles that are completed in 15 seconds
The shorter the pendulum the more cycles that are completed in 15 seconds
A ____cm pendulum is the best length for a pendulum that would keep accurate time
NOTEBOOK ENTRY

25. CONCLUSION Look at your prediction again.
How did the evidence support your prediction?
Do you wish to affirm or revise your prediction? Why?
My prediction was accurate because…..
I wish to revise my prediction because…
NOTEBOOK ENTRY 25

26. CONCLUSION Now write a concluding sentence using the stem:
“Today I learned … . “ Or
“In conclusion, … .”
NOTEBOOK ENTRY 26

27. REFLECTION
Think about the investigation we just completed. Use one of the stems below to write a reflection regarding the investigation.
What if …?
What really surprised me about this investigation was … ?
A new question I have now is… ?
I want to know more about ... ?
I am confused about … ?
NOTEBOOK ENTRY 27