POLYMER CAPT QUESTIONS:
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
Stretching Experiment Revisited
Students performed the following investigation.
Procedure:
1.) Cut a 5 cm piece of plastic from each of the following:
i. dry-cleaning bag
ii. kitchen wrap
iii. plastic sandwich bag
iv. plastic grocery bag
2.) Hold the sample of the dry-cleaning bag between thumb and forefinger.
3.) Attach a clamp to the bottom of the sample
4.) Add 2.5 kg of mass to the bottom of the sample and measure the length that the plastic
stretches.
5.) Repeat for the other samples.
6.) Record data in the table.
The students recorded the following data from their investigation.
Stretching Ability
Plastic Type
Trial 1
Dry-cleaning bag
23 mm
Kitchen wrap
16 mm
Sandwich bag
14 mm
Grocery bag
7 mm
1. What two variables were held constant in the above experiment?
a. type of plastic, mass added
c. type of plastic, and size of sample
used
b. mass added, time allowed for
d. mass added, size of sample used
stretching
2. All of the following are possible reasons for keeping these variables constant except__________.
a. All plastics have the same elasticity. c. The width needs to be constant so
the force is distributed ove the same
width
b. The length needs to be constant so d. The hanging mass needs to be the
the % of stretch is consistent
same so the force is the same.
between samples.
3. All of the following could be possible hypothesis that the students were testing except________.
a. If the same mass is used to stretch 4 c. If different lengths of plastic are
types of plastic, then the drystretched, then the longest piece will
cleaning bag plastic will stretch the
stretch the most distance.
most distance.
b. If 4 different types of plastic bags are d. If 4 different types of plastic bags
stretched, then dry-cleaning bag and
kitchen wrap will stretch the most
distance.
are stretched, then the sandwich bag
and the grocery bag will stretch the
least amount of distance.
How Tough is Tough?
Students performed the following investigation.
Procedure:
1.) Cut a piece of plastic from each of the following:
i. dry-cleaning bag
ii. kitchen wrap
iii. plastic sandwich bag
iv. plastic grocery bag
2.) Wrap 5 large ball bearings in the plastic and tie off with a rubber band.
3.) Drag the ball bearings/plastic across 10 cm of fine sand paper.
4.) Repeat dragging until a hole (at least 1 cm across) is formed.
5.) Record the number of passess required for the hole to form, in the data table.
The students recorded the following data from their investigation:
Plastic Type
Dry-cleaning bag
Kitchen bag
Sandwich bag
Grocery bag
Toughness
Number of passes to form hole
1
2
4
7
4. Which of the following is a valid conclusion based on the student’s data?
a. The sanwich bag is the toughest of c. The grocery bag is the least tough of
all the plastics tested
all the plastics tested
b. Kitchen wrap holds up better than all d. Plastic associated with food is
the other plastics tested when
tougher than the other plastics tested
dragged across sandpaper
that are associated with clothes
5. All of the following are ways that students could have improved on this experiment except_____.
a. Students could have done multiple c. Students could have checked for
trials and averaged the data
holes every 5 cm of dragging
distance
b. Students could have used any holes d. Students could have specified the
created in the plastic as indicators or
size of the plastic piece they cut
toughness