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

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

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

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

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

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

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

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

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

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.

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

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

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?

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

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

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

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

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

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 2 4 6 8 10 12 14 16 18 20 22 24 A 38cm pendulum completes 12 cycles in 15 seconds Y-axis: Dependent Variable The number of cycles depends on the length of the pendulum 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 X-axis: Independent Variable Length of Pendulum (cm)

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

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

MAKING MEANING CONFERENCE Listen and discuss SHARE DATA COLLECTED 22

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

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

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

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

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