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European Journal of Applied Sciences – Vol. 10, No. 3
Publication Date: June 25, 2022
DOI:10.14738/aivp.103.12374. Sharma, O., & Sharma, D. (2022). “Can Temperature and Pressure Change the Elasticity and Hooke’s Beyond Limit of Rubber
Bands?”. European Journal of Applied Sciences, 10(3). 125-140.
Services for Science and Education – United Kingdom
“Can Temperature and Pressure Change the Elasticity and
Hooke’s Beyond Limit of Rubber Bands?”
Om Sharma
Natick High School, Natick, MA, USA
Dipti Sharma (PhD)
Emmanuel College, Boston, MA, USA
ABSTRACT
In this report, a scientific research project is presented that is done for 2022
Massachusetts State Science Fair (MSEF) on rubber bands. This research work
shows how the effect of temperature and pressure can change elasticity of the
rubber bands those are found at home and used in everyday life. This work is done
during COVID 19 time and shows how hands on activities can be performed to
continue research work at home or in limited resources when it is not possible to
go out very frequently. It is found after experimentation that rubber bands show
more flexibility with lower spring constant and stop obeying Hooke’s Law on lower
values of force applied to them under conditions of high pressure and temperature.
Keywords: Physics, rubber bands, temperature, pressure, heat, cool, stretching, elasticity,
Hooke’s Law.
INTRODUCTION
Physics is involved almost everywhere that you see around you every day. No world is possible
without Physics. During COVID 19 when it is hard to go out and perform experiments in
laboratories, it became a point of our interest that how Physics experiments can be done at
home with easily available materials that is used in everyday life. How to be more creative and
thoughtful and find a good way to perform some hands-on activities and experiments to show
connection of Physics with material and to the world. Some studies can be seen on this type of
work that is done during COVID 19 situation. [1-2]
As weather and seasons change, the temperature of the environment changes. Pressure applied
to any object can also be changed. So, this thought can be applied to rubber bands to see how
elasticity and spring constant of the rubber bands change when temperature and pressure are
changed following Hooke’s law.
Rubber bands are easily available materials in daily life. Rubber bands are good material to be
tested for Hooke’s Law. [2] Some people have used rubber bands for classrooms studies to learn
how they follow Hooke’s law. [3] Rubber bands are elastic in nature. When you stretch them,
they extend and when you release force applied, they go back to its original shape. Rubber has
this useful property for two reasons. First, rubber molecules have a peculiar structure and
arrangement; second, those molecules are always moving around, because the rubber is
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European Journal of Applied Sciences (EJAS) Vol. 10, Issue 3, June-2022
Services for Science and Education – United Kingdom
warmer than a temperature of absolute zero. In any material warmer than absolute zero, the
molecules are always moving around in a tiny, random, jiggling motion. [4]
Rubber is made of molecules shaped like strands of spaghetti. If you stretch a rubber band, you
pull those spaghetti-shaped molecules into a straight line. But the molecules are still moving
around. They shake from side to side and bump into each other. Because of that motion, the
molecules tend to spread out sideways; so, they must "un-straighten," curl up, kink, tangle. That
makes them pull inward on the ends of the rubber band. The stretched rubber tries, so to speak,
to become short, thick, and flabby so the molecules will have more room to move around
sideways. The rubber band snaps back. [4-6] So, the elastic quality of rubber comes from its
interconnected spaghetti-shaped molecules, and from the tiny, random, jiggling motion of those
molecules. That motion causes the molecules to resist straightening. [5-6]
Some people think that it shrinks when you heat it up and expands when you cool it down, but
some may think opposite to it. In warm condition, the rubber band molecules move faster, tend
to shake sideways more, and therefore pull harder at the ends, than in a cold condition. rubber
band. A rubber band will squeeze a package harder if it's been in the sun than if it's been in the
freezer, some people think in this way. [4-7] But some may think rubber bands gets loose when
it heats up and shrinks down when cools down. It means temperature and pressure can change
quality of rubber bands and their behavior. Our interest is to see that change. Some literature
can be seen on temperature effects on bands here. [8]
EXPERIMENAL DETAILS
Seven types of rubber bands varying in thickness are used for pressure experiments, shown in
Figure 1(a), and Three types of rubber bands varying in thickness are used for temperature
experiments, shown in Figure 1(b).
Figure 1: (a) Set of seven rubber bands with decreasing thickness for pressure measurements.
(b) Set of three rubber bands with decreasing thickness and length for temperature
experiments
The rubber bands were hung on a wooden stand and a hanger was attached on it after
measuring bands’ initial length, width, and thickness without hanger. The change in length of
the bands were measured by adding more masses on it consistently for each band at room
temperature of 22 oC. using Hooke’s law, shown in equation 1, spring constant of each rubber
band is found at room temperature.
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Sharma, O., & Sharma, D. (2022). “Can Temperature and Pressure Change the Elasticity and Hooke’s Beyond Limit of Rubber Bands?”. European
Journal of Applied Sciences, 10(3). 125-140.
URL: http://dx.doi.org/10.14738/aivp.103.12374
F = k. dl --- (1) Hooke’s Law
F (M*g) is force applied to the rubber band, m is mass hung, g is gravity of Earth, k is spring
constant, dl (l – lo) is the change in length, lo is the initial length of the rubber band, l is the final
length of the rubber band.
For Pressure measurements, the pressure of the band was changed in two ways, (a) varying
force or weight applied on band keeping its cross-sectional area constant (picking one band at
a time.), (b) varying cross-sectional area but keeping force or weight applied same (keeping one
mass but comparing with different thickness bands.). The pressure of the bands is changed
from 42 kPa to 6250 kPa keeping them on room temperature of 22 oC.
The equation of pressure can be given as:
P = F/A --- (2)
Where P is pressure, F is force applied, A (w*t) is cross-sectional area for rectangular bands, w
is width and t are thickness of bands. For circular bands, A (pi*r^2) is cross-sectional area
where r is radius of the bands.
For Temperature Measurements, bands from the set of 3 bands were used to find spring
constant following same method as written above after treating each band on various
temperatures. The temperature of the bands was changed by putting them in freezer (0 oC),
room temperature (22 oC), and hot water by heating water on gas (42 oC). Temperature of
the bands are changed from 0 oC to 42 oC keeping their pressure same by using one type
of band at one time. Then their spring constants were compared as function of
temperature.
DATA COLLECTION AND RESULTS
Pressure Experiments:
(a)Data Collection for Pressure measurement
Table 1: Data for cross-sectional area of seven bands used for pressure measurement in rubber
band set # 1
Bands W(cm) t(cm) A (cm^2) A(m^2)
R1 0.65 0.18 0.117 0.0000117
R2 0.55 0.15 0.0825 8.25E-06
R3 0.5 0.13 0.065 0.0000065
R4 0.4 0.12 0.048 0.0000048
R5 0.35 0.11 0.0385 3.85E-06
R6 0.14 0.14 0.0196 1.96E-06
R7 0.12 0.12 0.0144 1.44E-06
Table 1 shows dimensions of rubber bands in the set #1.
Table 2: Data for effect of pressure on rubber bands
Table showing how pressure of the band is increasing (a) when their cross-sectional area is
constant, but force applied is increasing (see any one column at a time only) or (b) how pressure