Scientific Inquiry and Modeling with ThinkerToolstuckeys1/VIPP/secondary_8_6_am.pdf · • Scientific Inquiry: A set of methods scientists use in studying the natural world and in

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Scientific Inquiry and Modeling with ThinkerTools

Christina V. SchwarzMichigan State University

[email protected]://www.msu.edu/~cschwarz

What is a model? Modeling?Scientific Inquiry?

• A model: a set of rules, representations, and reasoning structures that allows someone to generate predictions and explanations.

• Modeling: a process of creating, using, evaluating, and revising models.

• Scientific Inquiry: A set of methods scientists use in studying the natural world and in creating explanations based on evidence derived from their work.

The importance of model-based scientific inquiry

• Models lie at the core of science.• While modeling becoming increasingly important

in science and engineering, scientific models and modeling is being advocated in science instruction because it can help students advance their conceptual theories.

• Engaging in modeling and reflecting on this process can also help students develop scientific skills and understand the nature of science.

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ThinkerTools

• Microworld simulation/modeling environment of force and motion (useful for grades 4-12).

• Developed by Barbara White at University of California at Berkeley. See White (1994) in Cognition and Instruction, and White & Frederiksen (1998) in Cognition & Instruction.

• Software available (Macintosh only) at http://thinkertools.soe.berkeley.edu/

ThinkerTools Inquiry Cycle

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

ThinkerTools Computer Screenshot

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ThinkerTools Computer Screenshot (cont.)

ThinkerTools Curriculum

• Engage in the ThinkerTools gravity curriculum module (see handouts)– design and conduct gravity experiments – use the ThinkerTools modeling software

• The curriculum follows the inquiry cycle as an instructional sequence.

Adapting ThinkerTools for the classroom

• What aspects of the ThinkerTools curriculum and software might be useful for adapting in your classrooms?

• ThinkerTools strengths include:– the modeling software and representations– the inquiry and modeling instructional sequence– the focus on knowledge about the nature and

purpose of models and modeling

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ThinkerTools: Force & Motion

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

Gravity and the Motion of Objects: Module 4 Part I

Name: _____________________________ Date: _________________ Teacher: ___________________________ Period: _______________

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* version (1/10/98)

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Module 4: Gravity Part I

Questions & Hypotheses

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

What is gravity and how does it affect objects? Gravity is an attractive force that affects everything around us. Gravity allows people to stand on the spherical earth (without falling off), it makes objects we throw up eventually fall down, and it keeps the earth revolving around the sun. In this module, you will research how gravity affects the motion of objects.

Before you begin, stop and think about the answers to these questions: (1) What do you think gravity is and how does it work? (2) What are some other examples of gravity’s effect on objects around us?

Predictive Question 1: How does gravity affect the motion of a falling object?

Imagine that you’re holding a ball out a sixth story window, and you drop it to your friend standing on the sidewalk.

First Hypothesis: (1) Use the picture on the next page to draw in the ball’s dotprints (the

position of the ball at every second).

(2) Also, fill in the data table to show what you think happens to the speed of the ball from the moment you let it go until your friend catches it.

(3) Then, make a graph using the numbers from your data table to show what happens to the ball's speed.

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Time

0.0 sec

0.5 sec

1.0 sec

1.5 sec

2.0 sec

Velocity

0 m/sec

_______

_______

_______

_______

Time

Vel

ocity

Does your prediction (shown in the picture, table and graph) indicate that the ball falls at a constant speed, or that its speed changes as it falls? Why do you think that happens?

Alternative Hypothesis: (You need an alternative hypothesis so that you can design an experiment to test which one fits the data better.) Use the picture, data table, and graph on the next page to show a different

hypothesis that you or someone else might have about what happens to the speed of a ball when you drop it from a sixth story window.

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Time

0.0 sec

0.5 sec

1.0 sec

1.5 sec

2.0 sec

Velocity

0 m/sec

_______

_______

_______

_______

Time

Vel

ocity

How is this hypothesis different from your first one? Why might someone believe this new hypothesis?

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Predictive Question 2:

FLOOR

BLUE BALL

RED BALL

Now imagine that you have two identical balls, one red and one blue. You hold the red ball about three meters above the floor and you hold the blue

ball a little higher, say about four meters above the floor. Suppose that you let go of both balls at exactly the same time. Which ball hits the floor first or do they both hit at the same time? Explain

your reasoning. Which ball is going faster when it hits the floor, or are they both going at the

same speed? Explain your reasoning.

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Self Assessment

• Read the definition of the scoring category

• Circle the score that you think your work deserves

• Justify your score by referring to specific parts of your work Communicating Well

Communicating Well. You clearly express your ideas to others through writing, diagrams, and speaking. Your oral and written reports are clear enough to allow others to understand exactly what you did in your research, as well as the reasoning behind it.

1 2 3 4 5 not adequate adequate exceptional To justify the score you have given yourself, explain how you have clearly communicated your hypotheses.

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Being Inventive

Being Inventive. You are creative and examine many possibilities in your work. You show originality and inventiveness in thinking of problems to investigate, in coming up with hypotheses, in designing experiments, in creating new laws or models, and in applying your models to new situations.

1 2 3 4 5 not adequate adequate exceptional To justify the score you have given yourself, explain how your hypotheses show originality and inventiveness.

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Module 4: Gravity Part I Investigate

Homework: Criticizing Someone Else’s Experiment

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

Before you design your own experiment to try to determine the answer to the predictive questions, read the student's report below. It describes an experiment that two students did to try to answer the first predictive question. Read and then analyze the report by carefully answering the two questions that follow it.

Research Report on the Effects of Gravity Question:

How does gravity affect the motion of a dropped ball?

Hypotheses:

My hypothesis was that objects accelerate (go faster and faster)

as they fall. Another hypothesis is that gravity pulls things down at a

constant speed. Investigation: (see next page)

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hackysack

floor

meter stick

meter stick

Equipment: 1 hackysack, 2 meter sticks, and 1 stopwatch. We held the hackysack two meters above the floor, dropped it and timed how long it took to reach the floor. We also watched its motion as it fell. We did this 3 times and collected the data shown below:

Trial Distance Time

1 2 meters 0.73 seconds 2 2 meters 0.70 seconds 3 2 meters 0.79 seconds

Average 2 meters 0.74 seconds Analysis:

Our data show that it took about the same amount of time each trial to reach the floor because the times that it took were pretty much the same. I used the average time of 0.74 seconds to calculate the velocity that gravity makes a hackysack fall: Velocity = distance ÷ time = 2 m ÷ 0.74 sec = 2.70 m/sec After the hackysack got going, it looked like it kept the same speed all the way to the floor which supports my second hypothesis.

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Model:

From our observations and data, we concluded that my first hypothesis was wrong. The law we discovered is that hackysacks fall at a constant speed of 2.70 meters per second. We think this happens because gravity is like God giving whatever you are holding one bonk in the downward direction as soon as you let go of it.

Evaluate:

What we learned is a little confusing. Our experiment tells us that speed doesn’t change as you fall, but I know that things fall faster if they start off higher, because when I jumped out of a tall tree I broke my leg when I hit the ground, but when I jump off a chair it's no problem. So I guess this means gravity gives a stronger pull when you get higher up, so even if skyscraper workers have a safety net right underneath them, it will have to be very strong because since they are up so high, they will be going very fast as soon as they fall off. One problem with our experiment is that we should have tried dropping the hackysack from a different height to make sure we are right. So, if we had time to do more research, we would try dropping the hackysack from both a higher height and a lower height.

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Your Analysis of The Report: 1. Do you think that this experiment is well designed so that it can answer

the research question? Explain. 2. Do you think, based only on the data from their experiment, that the

conclusions make sense? Explain your reasoning.

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Module 4: Gravity Part I Investigate

Designing a “Better” Experiment

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

Question:

How does gravity affect a falling object?

Hypotheses:

First Hypothesis:

Alternative Hypothesis:

Experiment:

Come up with a plan for a simple experiment that will clearly determine whether your first hypothesis or the alternative hypothesis is correct. Use the space on the next page to draw a diagram of your set up. Then briefly explain what you would do and how this would prove which (if any) of the two hypotheses is correct.

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Draw a sketch to show how you will set up your lab equipment. Explanation of how your experiment would work and how this would prove or disprove the two hypotheses:

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Module 4: Gravity Part I Analyze, Model, & Evaluate

Carry Out, Analyze, Model and Evaluate Your “Better”

Experiment

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

Carry out your "Better Experiment." Then write a research report that goes through the inquiry cycle by following the outline below. Question

Clearly state the research question. Hypotheses

State the two hypotheses that you are investigating. Investigation

Plan your experiment. (copy or revise from the previous page) • Draw a sketch of how you set up the lab equipment. • Describe how you used the equipment to carry out your experiment.

Show your data in tables, graphs, or some other representation. Analysis

Simplify your results and look at the patterns in your data.

Which of your hypotheses do your data support? Explain how you know. Model

Summarize your results in the form of a law and/or equation that describes and predicts how gravity affects the motion of a falling object.

What is your theory about how and why gravity has this effect? Evaluate

Evaluate your model. Is it accurate, reasonable, and useful?

How can your model be applied to other situations?

Describe your model’s limitations

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• What remains to be learned about gravity? • What further investigations would you do if you had more time?

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Carry Out Your Experiment

then write a

Research Report

(follow outline on previous page)

on

Your Own Lined Paper

and

Turn it in

to

Your Teacher

Date Due:

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Self Assessment of Your Lab Experiment and Research Report

Being Systematic. You are careful, organized, and logical in planning and carrying out your work. When problems come up, you are thoughtful in examining your progress and deciding whether to alter your approach or strategy.

1 2 3 4 5 not adequate adequate exceptional Justify the score you have given yourself.

Understanding the Processes of Inquiry. You show and explain how you made your predictions, how you designed and carried out your experiments, how you analyzed your data to create laws and models, and how you applied your laws and models to new situations.


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Analyze, Model & Evaluate

Exploring the Newtonian Computer Model

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

Computer Activity 5.2: A Falling Dot

In this activity, a dot will fall to the floor under the influence of gravity. Your goal is to collect data to prove or disprove the following hypotheses about the effects of gravity on the velocity of the dot as it falls:

(1) the dot falls at a constant speed;

(2) the dot accelerates as it falls (it falls faster and faster);

1. Start Computer Activity 5.2. The dot will begin to fall when you press the

spacebar. Watch the datacross carefully. To run the experiment again, choose Reset on the Run Menu, and then Run or Run Newtonian. You can rerun the experiment as many times as you like.

a) Did the dot appear to fall at a constant speed or to accelerate as it

falls?

b) Sketch and describe two things on the screen that make you believe

your answer to the previous question (a).

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2. To see the velocity of the dot as it fell, go to the Measure Menu and

choose Show Data Table. A Data Table like this will pop up:

Time

The Dot's Y Velocity

1 0.0 sec

2 1.0 sec

3 2.0 sec

4 3.0 sec

5 4.0 sec

6 5.0 sec

The first column just gives each dotprint a number. The second column gives the clock time at which each dotprint was made, and the third column gives the velocity of the dot at that time.

a) From the data table created by the computer:

Fill in the missing data in the table above.

Then, use your data table to make a graph below.

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Time

Vel

ocity

b) What happened to the dot’s velocity at each time step?

c) Make a law that would help you to predict the change in velocity of the

dot at each second due to gravity: d) Suppose that you turned gravity off, and you wanted to “simulate”

gravity by applying impulses to the dot. Based on your data, what would you have to do?

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3. Now, you are going to experiment with different strengths of gravity. Imagine you are on a planet where gravity is much stronger.

(The rest of activity 5.2 about changing the strength of gravity is optional. Work on this when you have completed your other work.)

a) What difference do you think this will make in how the dot falls?

To change the strength of gravity in ThinkerTools, you have to first go to the Run Menu and put ThinkerTools in Design Mode. To change gravity, go to the Activity Menu and choose Gravity. Then move the slider control on the left side of the Pop-up Screen (Gravitational Field) to a higher setting such as 2 (for twice the gravity), and click on OK. (Do not use Attractive Forces on the right side of the Pop-up Screen.) To run the experiment, choose Run in the Simulation Menu. Run the activity and look at the dotprints and the datacross. Increasing the strength of gravity in the ThinkerTools computer model just makes gravity stronger. It doesn’t change it in any other way.

b) What happens to the velocity of the dot? Is it falling more or less quickly than it did before you changed the gravity?

c) Why do you think increasing the strength of gravity had that effect?

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To see the data table made by the computer when the dot fell, go to the Measure Menu and choose Show Data Table. The data table will pop up.

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d) Fill in the dot’s Y Velocity at each time step: (The dot’s Y velocity is the vertical velocity of the dot)

Time The Dot's Y Velocity

1 0.0 sec 2 1.0 sec 3 2.0 sec 4 3.0 sec 5 4.0 sec 6 5.0 sec

Then, use your data table to make a graph below.

Time

Vel

ocity

e) What happened to the dot’s velocity at each time step?

f) Modify your law for predicting the change in velocity of the dot at each

second to allow for different strengths of gravity.

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Computer Activity 5.3: Falling Dots In this Activity, you will use ThinkerTools to explore predictions about the velocities of two balls falling from different heights.

In the computer simulation, two dots are at different heights above a floor with gravity turned on. When you press the spacebar, the dots will be released.

To rerun the experiment, choose Reset from the Run Menu, and then choose Run or Run Newtonian. 1. Which dot hits the floor first? Why?

2. Which dot has the highest final velocity? Why?

3. Could you have answered Questions 1 and 2 if you only had the dotprints

to look at? Explain why or why not.

4. Compare the pattern of the first four dotprints for each falling dot.

What do you notice, and what does this mean? (Hint: Looking at the computer’s data table and making a graph might help you answer this question.)

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Self Assessment Now you will evaluate the work you just did. Using the Tools of Science

Using the Tools of Science. You use the tools and representations of science appropriately and effectively. The tools you use include computers, lab equipment, and instruments for making accurate measurements. The representations include diagrams, tables, and graphs for clearly displaying data and helping you discover laws.

Circle the score that you think your work deserves

1 2 3 4 5 not adequate adequate exceptional Explain how your work with the software and the different representations justifies the score you have given yourself.

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Reasoning Carefully

Reasoning Carefully. You reason carefully using scientific data and models. For instance, you show how your data support your conclusions. You also create a carefully-thought-out model to explain your data. And you examine the applications and limitations of your research.


1 2 3 4 5 not adequate adequate exceptional Justify your score by explaining how you reasoned carefully as you worked with the computer activities and analyzed what happened to answer the questions.

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Module: Gravity I Model

Creating a Model of Gravity

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

You have now analyzed the results of your experiments in the real world and on the computer, and you have created a preliminary model of how gravity affects the motion of objects. Your next step is to create a more explicit model of gravity on the computer and envision the effects of this model by running simulations with it. Creating an explicit model on the computer is a very important step in the scientific process because it allows you to test your model. You will be able to ‘see’ if you have created a good model. If your chosen model doesn’t fit your experimental data, finding this out might give you some ideas for how you want to revise it. In order to do this, you’ll need to summarize what you’ve found into a rule about how gravity affects the motion of a falling object. Effect of Gravity on Speed Rule: Gravity causes a falling object to:

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Model Activity: Computer Modeling.

Directions For How to Make Your Own Computer Model: 1) Go to the computer and open Computer Activity 5.2 Falling Dot. 2) Under the Edit menu select Model Design. 3) Read the rules for the Effect of gravity on speed. 4) Select the rule that most closely resembles your Effect of Gravity on

Speed Rule by clicking the button next to that item. Then, press okay. 5) In the Justify your answer box that pops up, type a response to the prompt,

“I think that this is true because:” Then, click the OK button. 6) Go to the simulation menu and select Run. 7) Once you have seen enough of the simulation, go back into the simulation

menu, and select Reset. 8) Go back into the simulation menu and select Run Single Step. Select Run

Single Step several more times until the computer repeats itself. Then select Reset from the simulation menu.

9) After you have finished running your simulation in regular and single step

mode, go to the Simulation menu and select Run Newtonian. Compare the Newtonian simulation with the one you selected. (Newton was a famous physicist from the 17th century who invented important models of force and motion.)

10) Once you have run the Newtonian simulation, reset the simulation and

choose Newtonian Single Step. Again, select Newtonian Single Step several more times until the computer repeats itself.

11) Repeat the ten previous steps by selecting different rules from Model

Settings and running the simulation.

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Place a check next to the rule you have determined most accurately describes how gravity affects motion of a falling object, and write in your reason.

Speeds Up. Gravity causes a falling object to speed up because:

Constant Speed. Gravity causes an object to fall at a constant speed because:

Slows Down. Gravity causes a falling object to slow down because:

Speeds Up To Constant Speed. Gravity causes a falling object to speed up until it reaches a maximum constant speed because:

For future reference, the rule and explanation you have given is your model of The effect of gravity on speed.

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Model

Homework 3: Thinking about Scientific Models

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

What is a scientific model?

In science, we have a special meaning for the word model. A model is a set of representations and rules that allow you to predict and explain what will happen. For example, the rule “roughly every twenty-four hours, the sun rises in the east because the earth rotates on its axis” can be thought of as a model. A model can also be a description of an object or system that attempts to explain all of its known behaviors.

Creating models is a critical part of doing science. For some scientists, creating models is their main goal. One way to create scientific models is to use a computer. For example, the computer program in ThinkerTools allows you to create models that describe and predict the motion of objects. Creating models with the ThinkerTools software can help us better analyze, clarify and express our theories about the behavior of objects and systems.

Models can also be useful to develop and test ideas. For example, different scientists can have different theories which can be programmed into computer models. Scientists can then play with these models to see implications of their theories and test their theories.

Here are some examples of computer models:

- computer models that astronomers use to study how galaxies interact and collide

- computer models that take into account the amount of pollution in our atmosphere and how that effects the weather patterns on the earth

- computer models of atoms and molecules

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In your own words, describe what you think a scientific model is:

Give two new examples of scientific models other than the ones already mentioned:

What makes your examples scientific models?

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Self Assessment



• Justify your score by referring to specific parts of your work Understanding the Science

Understanding the Science. You show that you understand the relevant concepts, laws, and causal models and can use them in doing your research and in predicting and explaining real-world phenomena.

1 2 3 4 5 not adequate adequate exceptional To justify the score you have given yourself, explain how your answers to the questions about scientific modeling show that you understand what scientific models are.

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Module 4: Gravity Part I Evaluate

Evaluating Your Model

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

Applications: An important aspect of modeling is to find out how well your model applies to various situations.

Refer back to your gravity model and use it to answer the following questions.

Application Question 1. You are part of a research team dropping crash-test dummies from different heights (5 meters and 10 meters). Which dummy is damaged more? (The damage to the dummies is proportional to the speed of their impact.) (circle your response below)

(a) They’ll both be damaged the same because they will both have been falling at the same speed. (b) The one dropped from the lower height (5 meters) will have greater damage because it will have been falling faster. (c) The one dropped from the higher height (10 meters) will have greater damage because it will have been falling faster.

Explain your response:

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Extension Question: Imagine that you were dropping these dummies on the moon. How would that affect your answer?

Application Question 2. You are the pilot in the Lunar Lander trying to land on the moon to deliver supplies to the outpost located on the surface. What does your model predict you should do in order to land your rocket safely? (pick one below)

The moon

Lunar Lander trying to land on surface of moon

(a) Nothing. Since the gravity will be slowing the Lunar Lander down anyway, you just need to make sure your landing gear is out.

(b) You’ll need to give your lander a steady series of blasts (a series of impulses) down towards the moon’s surface in order to counteract the steady pull on your ship by the moon’s gravity.

(c) You’ll need to give your lander one large blast down towards the moon’s surface in order to counteract the one large tug on your ship by the moon’s gravity.


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Extra Credit: Is gravity larger, smaller, or the same at different distances between objects? Is this relevant to the different heights from which objects fall on the surface of the earth? (You might be surprised to find out the answer to this question!)

Projects ideas for you to explore sometime: How does the mass of an object affect what gravity does to its motion? (You

will eventually be able to use the computer model to test your theories) What does this tells you about the gravity from larger and smaller planets in the solar system?

What is escape velocity and why is it important? Class Debate and Consensus: Your teacher will take a poll of the class to see who agrees with the four different models. (Or alternatively to see whether you think gravity causes objects to speed up or fall at a constant speed.) Be prepared to defend why you chose your model with evidence, as well as how your model worked in the application section of this module. If there is disagreement in the class, be prepared to debate your model with others in the class. In your discussion, don’t forget to mention how your model explains your answers to your predictive and application questions. You might also want to explain your model from the first module (motion with no force like friction) since it is important to understanding your gravity model.

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Self Assessment for the Entire Module

Give your work on the module an overall score.

5 = Exceptional

4 = Good

3 = Adequate

2 = Poor

1 = Inadequate

Justify your score based on your work.

Who was your research partner(s) for this module?

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ThinkerTools: Force & Motion

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

Gravity and the Motion of Objects: Module 4 Part II

•

Name: _____________________________ Date: _________________ Teacher: ___________________________ Period: _______________

1

* version (1/20/98)

2

Module 4: Gravity Part II

Questions & Hypotheses

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

In this module, you will explore gravity in a different context: How gravity affects the motion of an object thrown upward.

Predictive Question:

How does gravity affect the motion of an object thrown upward?

Imagine that you are holding a ball and you throw it up in the air.

Describe the ball’s motion (speed and direction) once the ball leaves your hand.

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First Hypothesis: Fill in the following table and graph to show what you think happens to the ball’s speed once it leaves your hand.

Time

0.0 seconds

0.5 seconds

1.0 seconds

1.5 seconds

2.0 seconds

Velocity

10 m/sec

_______

_______

_______

_______ Time

Vel

ocity

What do your table and graph indicate about the motion of the ball?

Why do you think that happens?

What force or forces are acting on the ball once it leaves your hand?

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Alternative Hypothesis: Use the data table and graph below to show a different hypothesis that you

or someone else might have about what happens to the motion of the ball that is thrown upward.

Time

0.0 seconds

0.5 seconds

1.0 seconds

1.5 seconds

2.0 seconds

Velocity

10 m/sec

_______

_______

_______

_______ Time

Vel

ocity

How is this hypothesis different from your first hypothesis? Why might someone believe this new hypothesis?

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Self Assessment

Communicating Well. You clearly express your ideas to others through writing, diagrams, and speaking. Your oral and written reports are clear enough to allow others to understand exactly what you did in your research, as well as the reasoning behind it.

1 2 3 4 5 not adequate adequate exceptional To justify the score you have given yourself, explain how you have clearly communicated your hypotheses.

Being Inventive. You are creative and examine many possibilities in your work. You show originality and inventiveness in thinking of problems to investigate, in coming up with hypotheses, in designing experiments, in creating new laws or models, and in applying your models to new situations.

1 2 3 4 5 not adequate adequate exceptional To justify the score you have given yourself, explain how your hypotheses show originality and inventiveness.

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Module 4: Gravity Part II Investigate & Analyze

Designing and Carrying

Out an Experiment

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

Question:

How does gravity affect the motion of an object thrown upward?

Investigate:

Can you think of any good, simple experiments to answer this research question? If so, use the space below to draw a diagram of your set up. Then carry out your experiment and analyze your data. (Hint: dotprint video analysis) If not, describe why conducting an experiment like this is difficult, and simply make some observations of the motion of an object thrown upward. Write down those observations and then analyze them.

Draw a sketch to show how you will set up your lab equipment.

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Data and/or observations from your experiment:

Analysis of your experimental data and observations:

Preliminary conclusions from your analysis:

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Self Assessment of Your Lab Experiment

Being Systematic. You are careful, organized, and logical in planning and carrying out your work. When problems come up, you are thoughtful in examining your progress and deciding whether to alter your approach or strategy.


Understanding the Processes of Inquiry. You show and explain how you made your predictions, how you designed and carried out your experiments, how you analyzed your data to create laws and models, and how you applied your laws and models to new situations.


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Investigate & Analyze

Exploring the Newtonian Computer Model

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

Computer Activity 5.4: “Throwing Up” In this activity, gravity is turned on. Your goal is to understand (and explain) what happens to the dot's velocity when you throw the dot upward. When you start this activity, the dot is resting on a floor. You can store up impulses to give to the dot by pressing the up-arrow key ( ⇑ ). The dot will be released when you press the spacebar. The datacross is present, and the dot will leave dotprints. Also, a data table will be created so you can look at the changes in the dot's velocity. For each upward velocity that you try, study the dot's motion, datacross, and dotprints to see what happens to the velocity of the dot when you “throw it upward.” 1. Before you begin, make a prediction. a) What do you predict will happen to the dot's velocity after you release it?

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2. Use the up-arrow key to store up impulses and then press the spacebar to apply

the impulses. Watch the motion of the dot and the datacross carefully. To rerun the experiment, select Reset and then Run or Run Newtonian.

a) Did the dot speed up or slow down as it went up? Why?

b) On the way down, did the dot speed up or slow down? Why?

3. To see the data table created by the computer as the dot went up and down, go to

the Measure Menu and choose Show Data Table. a) Fill in the dot's Y Velocity at each timestep in the data table:

Time The Dot's Y Velocity

1 0.0 sec 2 1.0 sec 3 2.0 sec 4 3.0 sec 5 4.0 sec 6 5.0 sec 7 6.0 sec 8 7.0 sec 9 8.0 sec

10 9.0 sec

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11 10.0 sec

b) Then, use your data table to make a graph below.

0

1

2

3

4

Time0 1 2 3 4 5 6

5V

eloc

ity

7 8 9 10 11

c) Invent a law that precisely describes how gravity affects the motion of

the dot. Your law should apply both when the dot is going upward and downward.

4. Now try using your law to answer an interesting question: What happens when you double the initial upward velocity? a) Predict what the dotprints going upward would look like for (i) an initial velocity of 2 (ii) an initial velocity of 4.

In the space below, draw the dotprints for these two cases side by side.

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b) Test your predictions on the computer by giving the dot an initial velocity

of 2 and then an initial velocity of 4.

In the space below, draw the actual dotprints side by side. (i) initial velocity = 2 (ii) initial velocity = 4 c) Was your prediction for the dotprints correct? d) Does doubling the initial upward velocity cause the dot to go twice as high?

Explain why or why not? Computer Activity 5.5: “Throw-Up” Game This final activity is a two-player game. In this game, two dots will appear on a floor and two targets will appear, one above each dot. Gravity will act. You can press the up-arrows keys ( ⇑ ) to give each dot an initial upward velocity. To release the dots, press the spacebar. Try to give each dot an initial upward velocity so that it will turn around exactly when it reaches the target. If the target is the exact turn around point for the dot, the target will catch the dot. Experiment with different upward velocities until

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you find the one that works. When you succeed, you will get a point added to your score and the target will move to a new location.

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Self Assessment

Using the Tools of Science. You use the tools and representations of science appropriately and effectively. The tools you use include computers, lab equipment, and instruments for making accurate measurements. The representations include diagrams, tables, and graphs for clearly displaying data and helping you discover laws.


1 2 3 4 5 not adequate adequate exceptional Explain how your work with the software and the different representations justifies the score you have given yourself.

Reasoning Carefully. You reason carefully using scientific data and models. For instance, you show how your data support your conclusions. You also create a carefully-thought-out model to explain your data. And you examine the applications and limitations of your research.


1 2 3 4 5 not adequate adequate exceptional Justify your score by explaining how you reasoned carefully as you worked with the computer activities and analyzed what happened so that you could answer the questions.

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Model

Evaluating Models of Gravity

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

Model. Now that you’ve done some experiments on how gravity affects the motion of an object thrown upward, you will further refine your model of gravity. Model Question 1: How have your experiments in this module affected your ideas about how gravity works? (Refer back to your hypotheses to see what you thought and how that might be different now.)

Model Question 2: We’ve written three models of gravity on the following page. Read them carefully, and write down whether you agree or disagree and why.

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1. Objects that are thrown upward carry their own force from your hand

which needs to die out before gravity can act. Once the force from your

hand has died out, gravity pulls the object back down.

I agree/disagree (circle one) with this because:

2. Objects that are thrown upward have their own force from your hand

which balances gravity until gravity eventually takes over and pulls the object

back down.


3. Once an object has been thrown upward, gravity is the only force acting on

that object. Gravity constantly pulls the object until it falls back down.


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Self Assessment



• Justify your score by referring to specific parts of your work Understanding the Science

Understanding the Science. You show that you understand the relevant concepts, laws, and causal models and can use them in doing your research and in predicting and explaining real-world phenomena.

1 2 3 4 5 not adequate adequate exceptional To justify the score you have given yourself, explain how your answers to the questions about the models of gravity show that you understand and have thought carefully about them.

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Evaluate

Evaluating Your Model

Question

Model

Evaluate

Hypothesize

Analyze

Investigate

Evaluate: An important aspect of modeling is to find out how well your model applies to various situations. See how well your revised gravity model applies to the following questions. Application Question 1. You are residing on the surface of a large asteroid somewhere in the Milky Way Galaxy. Your asteroid, which has been traveling in space for the last 3000 years, is heading near a large star. What does your model predict will happen to your asteroid? (pick one)

(a) Since your asteroid is moving, its force of motion hasn’t died out, so the star’s gravity will not affect your asteroid's motion through the galaxy.

(b) The star’s gravity will overcome your asteroid’s motion (even though the asteroid still has internal force) and the star will likely pull your asteroid directly towards it.

(c) The star’s gravity is acting constantly. If your asteroid travels within the star’s gravitational field, it will pull you towards it, probably forcing your asteroid to orbit forever.


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Application Question 2. How does the gravity that you’ve modeled on earth relate to the gravitational force between planets? (This is not an easy question!)

Application Question 3. What are some ways of applying what you now know about gravity to things around you or to events that happen in outer space?

Class Debate and Consensus: Prepare a research report for other students explaining what you have learned from this module. (So that students who have not completed this module will get a chance to learn the material.) Your teacher will give you an opportunity to present your report. Alternatively, your teacher may take a poll of the class to see who agrees and disagrees with the three different gravity models. Be prepared to defend why you chose the model you did with evidence, as well as to explain how this model was useful when you used it to answer the application questions. If there is disagreement in the class as to the best model, be prepared to debate your choice with others in the class.

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Self Assessment for the Entire Module

Give your work on the module an overall score.

5 = Exceptional

4 = Good

3 = Adequate

2 = Poor

1 = Inadequate

Justify your score based on your work.

Who was your research partner(s) for this module?

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Documents

Scientific Inquiry and Modeling with ThinkerToolstuckeys1/VIPP/secondary_8_6_am.pdf · • Scientific Inquiry: A set of methods scientists use in studying the natural world and in