Truss Design on Mass Supported Before Failure

PURPOSE

The purpose of this experiment was to determine which of three truss designs would hold the most mass.

I became interested in this idea when I found out that roofs of buildings had trusses. I wondered how much weight trusses could hold before collapsing.

The information gained from this experiment could help engineers better understand which of the three designs of trusses could hold the most load. Also people who live in areas with lots of snowfall or high wind need strong roofs built with well-designed trusses. 

HYPOTHESIS

My hypothesis was that the King-post truss would hold the most mass.

I based my hypothesis on a previous study done in 2000 by 6th grader Aaron John, “Mass supported by King-post and Queen-post Truss Designs.” He concluded” that the King-post design was the most successful by standing the most weight.” 

EXPERIMENT DESIGN

The constants in this study were:

•    Method force was applied to each truss.

•    Type of wood used to make each truss.

•    Vernier force probe used to measure the force on the truss before collapsing.

•    The size of each truss.

•    Laptop to record the data.

•    Glue used to build the trusses. 

The manipulated variable was the truss design. 

The responding variable was the amount of force each truss could withstand before failure.

To measure the responding variable, I used a Vernier force plate attached to a laptop running Logger Pro 3.1 software.

MATERIALS

QUANTITY	ITEM  DESCRIPTION
3	Thin balsa wood sticks
1	Vernier force plate
1	Notched wooden block
1	Laptop
1	Hot glue gun
1	Glue

PROCEDURES

1.    Building the trusses.

a)    Buy several pieces of thin balsa wood. 

b)    Hot glue three wood pieces in the shape of a triangle, 15 cm long on each side

c)    Hold the part of the truss you are gluing for 60 seconds so it will set.

d)    Make sure each truss is the same size.

e)    Repeat steps b-d eight times so you have a total of nine trusses.

f)    Start building the main vertical struts that are going to be inside in every truss design.

g)    To make it easier, angle the cuts on the struts so they into place better. 

h)    Hot glue the struts inside the trusses from apex down to center of the bottom member. 

i)    Build all nine trusses to have this center post.

j)    Set three of these trusses aside and label “King-post”

k)    Take three of the basic trusses and add additional struts to make Queen-post trusses.  They need mini-struts hot glued going from the bottom of the center post out to the center point of the side members.  Set aside and label as “Queen-post”.

l)    Take three of the basic trusses and add additional struts to make Graf-post trusses.  They need mini-struts hot glued going from the bottom corners of the truss to the center point of the center post. Set aside and label as “Graf-post”.

m)    Create a notched wooden block for applying force to the apex of the truss. The notch in the wood exactly the angle of the apex on the truss. 

2. Setting up force system. 

a)    You should have a Vernier force plate and a computer to do this experiment.

b)    Set up the computer so it can read the force recorded from the force plate using Logger Pro interface box.

c)    The computer has to have a Logger Pro 3.1 software, so it can read the force recorded from the force plate.

d)    Make sure the force plate is connected during the experiment when measuring the force of each truss design before failure.

e)    Calibrate the force plate to read zero when no force is applied.

3. Testing truss 1

a)    Apply force straight down on the truss so the force plate can read the force and send the information to the computer.

b)    Apply force by using the notched wooden block.

c)    Put the bottom of the truss on the force plate and put the notch on the top angle of the truss.

d)    Start the data collection of the computer.

e)    Start applying steady force with your hand.

f)    You need to keep adding more and more force until the truss finally breaks.

g)    Once the truss actually breaks, then go over to the computer and record the highest force just before failure.

h)    Do the same thing for trial 2 and 3 by repeating steps 3a-3f.

 4. Testing truss 2

a)    To test truss type 2 repeat steps 2-3.

b)    Be sure to conduct 3 trials

5.   Testing truss 3 

a)    To test truss 3, repeat steps 2-3.

b)    Do the same thing for all three trials.

c)    For each truss find the average of force from the three trials.

d)     Use the average results to compare the truss designs. 

6.   Compare

RESULTS

The original purpose of this experiment was to determine which of three truss designs would hold the most mass.

The results of the experiment were that the Graf-post held 214 newtons, the Queen-post held 175 newtons, and the King-post held 129 newtons.

CONCLUSION

My original hypothesis was that the King-post truss would hold the most mass.

The results indicate that this hypothesis should be rejected, because the Graf- Post truss held more force before failure than the King-Post.

After thinking about the results of this experiment, I wonder if the type of wood would make a difference in the outcome of the results. Then I also wondered if the type of glue would make a difference.

If I were to conduct this project again I would build and test many more models of each type, probably 10. I would be more exact when cutting and fitting the struts.  Then I would test a couple more types of typical truss designs. I would also build my trusses so the bottom member was stronger than the sides.

 Researched by --- Scotty G

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Ability of Seventh Graders to Memorize a Word List

 PURPOSE

The purpose of this experiment was to determine the effect of colored versus black text on the ability of seventh graders to memorize a word list.

I became interested in this idea when my mom and I were watching television. I noticed that almost every commercial was in bright colors rather than black. This made me wonder if there was a reason for that. I’ve also always wanted to have a chance to study human memory. 

The information gained from this experiment could help people who make advertisements. It will also help people who want to improve their memory. Teachers may also want to know so they can have their students remember study terms better.

HYPOTHESIS

My hypothesis was that seventh graders would remember the words printed in colored ink better than black ink. 

I based my hypothesis on the results reported by Mary LaBissoniere who did a similar project “The Effect of Color on Memory Retention of Items on a List” in the year 2000. She concluded, “Colored words were remembered better than those printed in black.” I also based it on the fact that almost all advertisements are in color.

EXPERIMENT DESIGN

The constants in this study were:

•    The number of words in each list

•    The amount of time to study the list

•    The amount of time to fill out the response sheet

•    Time passing between studying and taking the quiz

•    The place to take the test

•    The difficulty of the test

The manipulated variable was the print color of the list the subjects were to memorize.

The responding variable was the number of words the subjects remembered. 

To measure the responding variable, I scored the subject’s responses using a list of the correct answers. Then I counted the number correct.

  

MATERIALS 

QUANTITY	ITEM DESCRIPTION
1	Classroom for testing
44	Tests
8	Desks
2	Experimenter scripts
8	Pencils
22	7th grade students

        

PROCEDURES

1.    Create word lists and tests

Ø Select words that are below the average seventh grade spelling level

 Ø Create 2 equally difficult lists with 25 words in each.  Do not alphabetize these words.

 Ø  Label one List A and the other List B

  

 Ø  Create a Test A by randomly adding an additional 25 words of similar difficulty to List. Do alphabetize these test items.

 Ø  Create Test B in the same manner, but be sure not to repeat any words previously used in Test A.

 Ø  Create an answer sheet for Test A, by marking the words in this test that were originally in List A.

 o   Create an answer sheet for Test B, by marking the words in that were originally in List .

 o   Create an instruction script to explain testing procedures to each group before they take the test

 2.   Randomly assign boys with permission slips equally to Test Group 1 and 2.

3.    Randomly assign girls with permission slips equally to Test Group 1 and 2.

4.    Arrange an empty classroom so that it has enough desks for one test group with the desks spaced far apart (about 1 meter.)

5.    Have Testing Group 1 come into the classroom and sit

6.    Read instructions to the group and answer questions.

7.    Using the testing schedule, give them the appropriate List (A or B) in the correct color (black or colored).

8.    Have them memorize the list for two minutes

9.    After two minutes collect the lists

10.    Wait five minutes before giving them the matching test sheet (have them play tic-tac-toe or another game on paper that has no words involved.)

11.    Pass out the test sheets and pencils

12.    Instruct them to circle exactly 25 words, those in the original List.

13.    Give the group 3 minutes to circle all the words they can remember.

14.    After three minutes collect all the tests and pencils

15.    Dismiss students to class

16.    Check their answers with answer key for this test

17.    Record the number correct

18.    Repeat steps 5-17 for groups two, three, and four

19.    Average scores for each treatment.  

20.    Compare the results to see if the students remembered words in colored ink or in black ink better.

RESULTS

The original purpose of this experiment was to determine the effect of colored versus black text on the ability of seventh graders to memorize a word list.

The results of the experiment were that seventh graders could remember words printed in black better than in color. According to the data the average words that were correct with black text were 19. For color the average words correct was 17.

CONCLUSION

My hypothesis was that seventh graders would remember the words printed in colored ink better than black ink.

The results indicate that this hypothesis should be rejected because according to the data the average words that were correct with black text was 19. For color the average words correct was 17.

After thinking about the results of this experiment, I wonder if girls would remember the words better than boys would.

If I were to conduct this project again I would make the words closer to the same reading grade level. I would also use many more subjects. 

Researched by ------ Whitney B

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Colored vs. White Paper On 7th Grade Math Test Scores

 PURPOSE

The first purpose of this experiment was to determine whether seventh grade students’ math test scores were affected by having the test printed on colored vs. white paper.

The second purpose of this experiment was to determine whether seventh graders preferred   tests printed on colored paper or white paper.

The third purpose of my experiment was to determine whether seventh grade girls’ or boys’ scores would be affected more by the paper color.

I became interested in this idea when I realized that I was able to do and remember work better when using colored paper. 

The information gained from this experiment could help educators know what color of paper is better for tests.  It would also show whether seventh graders prefer taking tests on colored or white paper.  Also it would show whether girls in the seventh grade are affected more or less by paper color than boys are.

HYPOTHESIS

My first hypothesis was that seventh graders would have higher test scores when taking the test on white paper.

My second hypothesis was that seventh graders would prefer taking the test on colored paper. 

My third hypothesis was that girls’ test scores would be affected more than the boys’ scores.

I based my first hypothesis on the results of Christian Hertel’s science project, “The Effect of Colored versus White Paper on Math Scores,” from the year 2004. She found that tests on white paper yielded the best results.

My second hypothesis was based on a small poll taken by fellow students in an after school science class. About 40% preferred to take a test on white paper, about 60%preferred to take a test on colored paper.

I based my third hypothesis on the observation that girls seem to pay more attention to color than boys.

 

EXPERIMENT DESIGN

The constants in this study were:

•    Number of questions on each test

•    Difficulty of tests

•    Amount of time to take tests

•    Testing environment (lighting, desk placement 50 cm apart, quiet noise level)

•    Subjects taking the tests

The manipulated variables were the color of paper the test was printed on and the results of boys vs. girls.

The responding variables were the number of correct answers.  

To measure the responding variable, I counted the number of problems correct using a scoring sheet.

MATERIALS

QUANTITY	ITEM DESCRIPTION
1	Stopwatch
20	Experimenter’s script scoring sheet (with group numbers)
20	Tests printed on colored paper (10 form A, 10 Form B)
40	Number 2 pencils
20	Desks and chairs
20	Tests printed on white paper (10 form A, 10 form B)

PROCEDURES

1. Obtain two equally difficult math quizzes and label one Form A and the other Form B.

 
2. Print enough Form A tests for all subjects but print half on colored paper and half on white.

3. Print Form B tests for all subjects. Print half on colored paper and half on white.

 
4. Randomly assign 7th grade subjects having a permission slip to one of four test groups: Group 1, Group 2, Group 3, and Group 4.

5. Arrange enough desks in an empty classroom so the subjects cannot see other subjects’ tests, spaced at least 50 cm apart

6. On each day of testing refer to the testing schedule to determine who to test and what test to use:

a. bring in one test group

b. explain what to do

c. answer any questions that might occur 

d. give them pencils

e. give them the appropriate form

i. Group 1: Form A  on Colored paper

ii. Group 2: Form A on White paper, 

iii. Group 3: Form B on Colored paper 

iv. Group 4: Form B on White paper

f.  Use a stopwatch and time them for 20 minutes 

g. After 20 minutes are up collect the tests

h. Send students back to class

7.  On day two repeat steps 5and 6 except use the following forms.

i. Group 1: Form B on White paper

ii. Group 2: Form B on Colored paper

iii. Group 3 :Form A on White paper

iv. Group 4: Form A on Colored paper

8.  At the end of day two give the test subjects a preference survey

to see what color of paper they preferred to take the tests on

9.  Count the number of problems correct and record them on the

scoring sheet (by color of paper and test form)

10.  Find an average for each of the four testing forms

11.  Record this information 

12.  Find a percentage for the total from all the subjects

13.  Record this information

14.  Sort the tests by gender of student

15.  Add together the total points of the boys then the girls

16.  Tally preference votes

17.  Average scores and compare for each gender

18.  Record the averages

 RESULTS

The first original purpose of this experiment was to determine whether seventh grade student’s math test scores were affected by having the test printed on colored vs. white paper.

The second original purpose of this experiment was to determine whether seventh graders preferred tests printed on colored paper or white paper.

The third original purpose of this experiment was to determine whether seventh grade girls’ or boys’ scores would be affected more by the paper color.

The results of the experiment were seventh graders did an average of 0.2 points out of 18 better taking a math test on white paper versus taking a math test on colored paper.  Seventh graders also seem to prefer taking a math test on colored paper rather then white paper, I discovered that 65% seventh graders prefer math tests on colored paper and 33% prefer taking a test on white paper.  My results also show that boys scored 0.2points (out of a possible 18) better than girls when taking the math test on colored paper and 0.6 points better than girls taking a test on white paper.

CONCLUSION

My first hypothesis was that seventh graders would have higher test scores when taking the test on white paper. The results do not give a clear indication that this first hypothesis should be accepted.  Although the seventh graders on average had a slightly higher score taking the test on white paper, the difference was extremely small.  In fact it is probably insignificant.  I think that if I redid my entire project with a new group of subjects that they could just as easily have an average that showed the opposite effect.  For this reason, I feel I must reject my first hypothesis.

My second hypothesis was that seventh graders would prefer taking the test on colored paper. The results indicate that this second hypothesis should be accepted, because 65% preferred taking a test on colored paper rather than taking a test on white paper.

My third hypothesis was that girls’ test scores would be more affected than the boys’ test scores. The results indicate that this third hypothesis should be rejected also because on average boys scores varied more between colored and white paper. The girls had almost exactly the same score on both colors.

After thinking about the results of this experiment, I wonder if using varied colors instead of yellow for all the tests would affect the test scores.

If I were to conduct this project again I would give my subjects more than twenty minutes to complete each test.  I would also test many more subjects. I would have my subjects do a much easier test.
 

Researched by ----- Brooke C

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