unit1-ls1-studentedition- 1.6

7/29/2019 Unit1-LS1-StudentEdition- 1.6

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1.6 Explore

Learning Set 1

ACCIDENT CHALLENGE


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1.6 ExploreWhat variables affect the collision distance?

The increasing number of dangerous accidents is a serious concern for all citizens of McFarland.

In an attempt to understand why some accidents are so dangerous the city decided to look at

whether vehicles were speeding. If the dangerous accidents are all from trucks that are

speeding, then the McFarland police could focus on enforcing the speed limit. The police set up

remote speed monitoring equipment and found that the majority of drivers were travelling the

speed limit. Despite driving the speed limit, some trucks were still involved in

severe/dangerous accidents.

The citizens of McFarland have suggested various reasons why some accidents might be more

dangerous than others. Some have argued that the posted speed limit (40 mph) is too high. In

other words, if drivers are driving the speed limit and stillgetting in severe accidents, then the

current speed limit is too high. Other citizens have focused on the type of the truck driving on

Park St. Some of the trucks driving to and from the factory are empty (because they have just

made a delivery) and some are filled (because they have just picked up a shipment). Some

citizens have argued that either the empty or the loaded trucks might be more likely to be in a

dangerous accident.

The citizens are bringing their ideas to the city council. The city council wants to use these

ideas to write proposals that could reduce the number of severe/dangerous accidents. One

problem is that the citizens ideas are only guesses; they have no data to support their claims

about the factors causing the severe accidents. The city council wants to write proposals based

on data, so that they have evidence that the proposals might work.

Therefore the city council would like data that suggests which factors might be contributing to

the dangerous accidents. If the posted speed limit were reduced, would there be less severe

accidents? Two slower speed limits have been proposed: 20 mph and 30 mph. Would this

matter? Which speed limit should be used? Is the type of truck an issue? Are empty or loaded

trucks more likely to be in a dangerous accident?


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1.6 ExploreYou will continue to use your model of collisions. This time you will conduct an experiment to

determine what effects the speed of the truck and the type of truck have on the severity of the

accident. This evidence will be used by the city council to decide which proposals would likely

reduce the severity of accidents at the intersection.

1.6: Part 1 of 5 Organize the Challenge

Before starting the investigation you need to design a new procedure. You will need a new

procedure because you have new information that is relevant to the challenge. To begin

thinking about changes to the procedure we will conduct a poll.

As a group, discuss the questions on the Poll Questions Sheet. Then, as a group, decide the best

answer to each question. Mark your answer on the Poll Questions Sheet. When your group has

answered all the questions, choose one person to report your answers to the class.

All groups will report their answers to the poll questions. As other groups are reporting their

answers, write down their answers on the Poll Results Sheet. When every group has reported

their data the class can look at the Poll Results Sheet and discuss whether all groups agree, or

why groups might disagree.

GROUPComplete the Poll Questions Sheetwith your group. When your

teacher is ready, share your answers with the class.

STUDENT Record each groups answers on the Poll Results Sheet.


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1.6 Explore


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1.6 ExploreUse a Think, Pair, Share to answer the following questions about the last procedure you

developed (the procedure in 1.4).

What changes would you need to make to your groups procedure in order to testdifferent speeds?

What changes would you need to make to your groups procedure in order to testdifferent truck types?

Answer these questions yourself, and then pair and discuss your ideas with a partner. Your

teacher will then ask some groups to share their answers. As groups share ideas about the

procedural changes, your teacher will help the class identify how to change the class procedure.

As a class, you will decide how to change the procedure to test these factors. Additionally, your

teacher will assign groups to the different conditions that need to be tested.

1.6: Part 2 of 5 Explore

In the last section your class decided how the procedure could be changed so that you could

test trucks traveling at different speeds and trucks with different masses. Therefore, you now

need to plan (and record) your new procedure. Use the Procedure Design Sheetto write your

new procedure. Be sure to include the important details for your tests. (Remember, your

group will test only two conditions. Your teacher should have assigned your group which two

conditions to test.)

Use a Think, Pair, Share to discuss what changes to your

procedure will be needed.

GROUP Complete the Procedure Design Sheetto record your procedureand the details for your two tests.

CLASS


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1.6 Explore

After you have planned your procedure, complete your investigation. For each condition your

group tests, conduct 10 test trials. Record your data on the Data Recording Sheet. Once your

group has collected all the data, calculate the average for each condition.

Run your two investigations following the class procedure.

Record our results on the Data Recordin Sheet.STUDENT


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1.6 Explore1.6 Part 3 of 5 Add to Your Understanding

You just conducted an experiment in your laboratory. Experiments can differ widely in what

they look like, but they generally have at least one independent variable and one dependent

variable. Additionally, experiments have many controlled variables.

An independent variable is a variable that the experimenter systematically changes during the

experiment. For instance, an experimenter might vary the amount of water that a plant gets, in

order to see how different amounts of water affect the length of roots that a plant grows.

A dependent variable, on the other hand, is a variable that the experimenter measures during

the experiment. Often, the independent variable is predicted to affect the dependent variable.

For instance, the experimenter might think that amount of water (independent variable) will

affect plant root length (dependent variable). In this case, the dependent variable (root length)

depends on the amount of the independent variable (water).

Likewise, you might hear people refer to a controlled variable. A controlled variable is a

variable that the experimenter holds constant. In other words, the experimenter keeps the

variable from changing. For instance, suppose the earlier experiment about plant root growth

was being conducted with five potato plants. The type of soil that the plants are growing in

might also affect root length. Because the experimenter is only interested in the effect of water

on root growth, he or she would need to be careful not to use different types of soil. Instead,

each of the five potato plants would need to get the same type of soil. In this example, soil

type is a controlled variable. Controlled variables are used to keep a procedure consistent.

1.6: Part 4 of 5

ShareSharing procedures and data is important for scientists and engineers because it allows

collaboration. Other scientists and engineers can use each others work and data to

understand a problem better. This is especially important when the problem is complex. For

instance, you only tested one speed. Other groups tested a different speed. Even though you


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1.6 Exploredid not test it yourself, you can use their data to understand how mass affects distance traveled

at different speeds.

Just seeing data alone is problematic. Remember how many problems you had getting

consistent data during early versions of your procedure? To evaluate someone elses data, you

often want to know the procedures they used to generate that data. This way you can

understand better how they collected their data.

Communicating procedures and data is important for scientists and engineers. You will practice

communicating your procedure and data now. We will use a poster session to report your

procedure and data using a poster as a visual aid. After your group creates your poster the

class will share their posters with each other.

When making your poster consider your audience. What information do they need to know in

order to understand your experiment? When making your poster, include the following

sections:

1. Question: What question were you testing? (What independent variable were youchanging?)

2. Prediction: What did you expect the result to be? (How did you expect the dependentvariable to change when the independent variable changed?)

3. Data: Paste your table of data onto your poster4. Results: What is the trend or results that you found?

After you have created your poster your group will display it in the classroom. Groups can walk

around and view other groups posters. Your teacher will select a few groups to present their

poster to the class.

GROUPAs a group, plan out and then make your poster. Be sure to

include all four sections.


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1.6 Explore

Poster Session

A poster session is an event

that helps scientists and

engineers communicate their

work to others in their

profession.

There are different types of

poster sessions, but all involve

a visual aid (a poster) that

contains important

information about a problem

and the methods and results

of the scientists/engineers

investigation of the problem.

Image courtesy: Science Education Research Center.

http://serc.carleton.edu/NAGTWorkshops/earlycareer2010/program.html

A poster session is a social event, with some people presenting posters and other people

walking around and talking with those presenters. The authors of the poster will use the

poster to help explain what he or she was doing, and to answer questions asked by the

audience. By communicating their work, poster sessions help scientists collaborate they

help others learn what has been done and what still needs to be done to solve a problem.

1.6: Part 5 of 5 Add to Your Understanding

You saw other groups data in the poster session. What would happen if you collected the data

from all the groups in your class? Remember that some other groups tested different speeds

than your group did. If you collect and graph the data for the entire class you might see trends

about how the speed of Vehicle A affects the distance that Vehicle B travels and how the mass

of Vehicle A affects the distance that Vehicle B travels. In a sense, all the groups would be

Poster Session. Display your poster in the classroom and view

other groups posters. You can ask them questions about their

procedure and data. A few groups will present their posters to

the class.

GROUP


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1.6 Explorecollaborating together in order to understand how two factors (mass and speed) affect the

distance that Vehicle B travels after a collision. Your teacher will help you collect and graph the

class data.

Now that you have collected the class data, you can create graphs to look at the data for all six

of the tests that the class conducted. Your teacher will use the data in the Class Data Table

Sheetto draw graphs on the Class Line Graph Sheet. You should follow along and draw the line

graphs on your copy of the Class Line Graph Sheet. Creating the graphs will give you a visual

representation of the trend of your data. It might help you understand the effect of varying the

mass and speed of Vehicle A.

STUDENT Report your two test condition means to your teacher. Record

each groups means on your Class Data Table Sheet.

STUDENT

Draw two line graphs on the Class Line Graph Sheet. One line

graph is for the empty truck and one line graph is for the loaded

truck.


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1.6 Explore

Graphing: Line Graphs

A line graph is a type of graph that

connects data points with a line. Line

graphs are often used to show a trend how data changes along some

ordered dimension.

For instance, suppose you wanted to

see how the number of sent text

messages changes over each weekday.

You could calculate the mean number

of text messages sent on Monday, themean number sent on Tuesday, etc. A

hypothetical graph of these data is on

the right. Each weekdayis on the X-

axis and Mean number of text

messages is on the Y-axis. Does the

mean number of text messages

increase, decrease, or stay the same

from Wednesday through Friday? On

which day were the fewest text

messages sent?

Now that you have the line graphs drawn, you should be able to interpret the data displayed in

the graphs. Your teacher will guide the class, helping you understand and interpret the data.

Consider these two questions.

For the loaded trucks, does speed increase the distance Vehicle B traveled? For the empty trucks, does speed increase the distance Vehicle B traveled?

0

2

4

6

8

10

12

14

Mon Tue Wed Thu Fri

Meannumberoftextmessages

Weekdays

CLASS Interpret the line graphs and answer the above questions.


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