TESLA Variables Unit: FOSS KIT

PendulumsPendulums

INTENDED CURRICULUM FOR TODAY’S LESSONINTENDED CURRICULUM FOR TODAY’S LESSON

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.

The Big Idea…

ENGAGING SCENARIOENGAGING 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?

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?

Focus Question Focus Question (What is the problem?)(What is the problem?)

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How can we…How can we…

How can we make a clock with a pendulum that would keep accurate time?How can we make a clock with a pendulum that would keep accurate time?

Discuss ideas with a partner for a possible focus question. Your focus question should be connected to what the scenario wants us to do…

New VocabularyNew Vocabulary

Pendulum•Any mass suspended on a rope, string, or arm that is free to pivot from an anchor point

Anchor Point

Mass

Cycle:One complete swing back and forth of a pendulum

String

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Cycle

Discuss your ideas with a partner, then write a prediction in your Discuss your ideas with a partner, then write a prediction in your notebook and be ready to share.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_________.

Prediction (related to the focus question) Prediction (related to the focus question)

Previous Knowledge Previous Knowledge

Share experiences with pendulumsShare experiences with pendulums

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

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

pendulum

pendulumor washer

or washer

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.

Testing the Standard Pendulum Testing the Standard Pendulum

# of Cycles in 15 seconds

Trial #1 Trial #2 Trial #3 Trial #4 Average

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What could you change in your pendulum system that might change the number of cycles in 15 seconds?What could you change in your pendulum system that might change the number of cycles in 15 seconds?

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String Length

Angle of Release

Mass

Designing and Experiment Designing and 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.

Designing an Experiment Designing an Experiment

Designing an Experiment 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: 38cmTime: 15 seconds

Angle of ReleaseMass: 1 washer

String Length: 38cmTime: 15 seconds

String LengthAngle of Release: 0*Mass: 1 washer

Time: 15 seconds

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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.

Collecting DataCollecting Data

Desk Top

60*

40*

20*

0*

Will the angle of release change the # of cycles in 15 seconds? Why…

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Will the angle of release change the # of cycles in 15 seconds? Why…

Variable: Angle of Release

# of cycles in 15 Seconds

Trial 0* 20* 40* 60*

#1

#2

#3

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Collecting DataCollecting Data

What does your data conclude about changing the angle at which the pendulum is released?

Let’s now find out if changing the mass (washer) will change the number of cycles in 15 seconds. (add more washers or objects)

Collecting DataCollecting Data

How do you think adding mass will affect the number of cycles?

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Where will the release point be if this is our standard pendulum system and we are testing for the variable of mass?

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?

We are now going to make new pendulums to determine if length is a variable that will affect the number of cycles.

Collecting DataCollecting Data

How do you think changing the length of the pendulum will affect the number of cycles?

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•Since this is a controlled experiment we will use a mass of one penny and a 0* angle of release.

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

Collecting DataCollecting DataVariable: 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

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What does your data conclude about changing the mass of the pendulum?

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

Interpreting DataInterpreting DataNumber of 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

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A 38cm pendulum completes 12 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.

Interpreting DataInterpreting DataNumber of Cycles in 15 Seconds

Leng

th o

f Pen

dulu

m (

cm)

A 38cm pendulum completes 12 cycles in 15 seconds

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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.

Interpreting DataInterpreting Data

Num

ber

of C

ycle

s in

15

Sec

onds

Length of Pendulum (cm)

Y-axis: Dependent Variable

The number of cycles depends on the length of the pendulum

X-axis: Independent Variable5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85

2

4

6

8

1

0

12

1

4

16

1

8

20

2

2

24

A 38cm pendulum completes 12 cycles in 15 seconds

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Interpreting DataInterpreting Data

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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?

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.

Interpreting DataInterpreting Data

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SHARE DATA COLLECTEDSHARE DATA COLLECTED

Listen and discussListen and discuss

MAKING MEANING CONFERENCEMAKING MEANING CONFERENCEMAKING MEANING CONFERENCEMAKING MEANING CONFERENCE

MAKING MEANING CONFERENCEMAKING MEANING CONFERENCEMAKING MEANING CONFERENCEMAKING MEANING CONFERENCE

•How do scientists use graphs to make predictions?

•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?

•Which pendulum design could be used to keep accurate time?

Claims and EvidenceClaims and Evidence

I claim that… I claim this because…

How can we make a clock with a pendulum that would keep accurate time?How can we make a clock with a pendulum that would keep accurate time?

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CONCLUSIONCONCLUSIONCONCLUSIONCONCLUSIONLook 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…

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CONCLUSIONCONCLUSIONCONCLUSIONCONCLUSION

Now write a concluding sentence using the stem:

“Today I learned … . “

Or

“In conclusion, … .”

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REFLECTIONREFLECTIONREFLECTIONREFLECTION

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 … ?

Think about the investigation we just completed. Use one of the stems below to write a reflection regarding the investigation.

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