Effect of Change in Temperature on the Spring Constant of a Metallic Steel Spring
Aim
This physics investigation aims to examine the effect of temperature change on the spring constant of a metallic steel spring.
Introduction
This investigation is linked to my long interest in and participation in Bungee jumping. In this game, I am particularly interested in how people are able to jump from great heights on elastic cords. This investigation is linked to my long interest in and participation in Bungee jumping. In this game, I am particularly interested in how people are able to jump from great heights on elastic cords. I realized that a person’s weight on the spring is similar to a mass hanging on a spring, and the extension of this spring could be a subject weight or force that acts on it.
The spring constant is the force ratio of a spring to its displacement (Dwivedi 1). The spring constant is calculated through the following general formula;
Figure 1: A Representation of Loaded Spring
Different factors could influence the constant of the spring represented in Figure 1 above. According to Garrett (2), the spring’s length, geometry, and material properties could directly influence the spring constant. Additionally, temperature could affect the spring constant due to changes in thermal expansion when the spring is heated or cooled. The interest of this investigation is to increase the temperature and examine the impact of this increase on the spring constant of a steel spring while controlling the spring’s length, geometry, and material properties.
Hypothesis
It is hypothesized that the spring constant of the steel spring will decrease with an increase in temperature. This hypothesis is supported by the study of Werner et al. (2), which supposes that when the temperature in an elastic body is increased, the metallic lattice’s atoms tend to vibrate with increased energy, making the atoms occupy more space. As a result, the spring’s length increase, leading to a reduction of stiffness.
Variables
Independent Variable
The Independent variable in this scientific investigation is temperature. The temperature will be varied from 250C to 500C increments of 50C using the hot water and measured by mercury thermometer (± 0.10C).
Dependent Variable
The spring constant of the steel spring will be the dependent variable. The calculation of this variable will be based on the mass of a 100 g mass and the change in the length of the spring.
Control Variable
The major control variables in this scientific investigation are presented in table 1.
Table 1: Main Control Variables, their Impact, and Control Mechanism
| Control Variable | Impact of the Variable | Mechanism of the Control |
| Mass | The size of the mass attached to the steel spring will directly affect the extension. Thus, the use of different masses will lead to inconsistent extensions across the trials. | One 100 g mass will be used in all the trials. |
| Steel spring | Variations of springs will vary the spring constants since different springs could have different properties. | A single spring will be used across all the trials of this investigation. |
| Experimental technique | Changing the techniques of conducting the experiment could lead to inconsistent results; for instance, heating the spring while hanging on the clamp stand in some steps and heating the spring in water before suspending on the spring. | A unified technique for performing the experiment will be ensured and maintained across all the trials. |
| Environmental temperature | Fluctuations in environmental temperature can lead to compressions and tensions of the spring leading to inconsistent extensions across the trials. | The entire experiment will be conducted in a single room to ensure maximum control in environmental temperature conditions. |
Apparatus
- A stopwatch
- A clamp stand
- An electronic beam balance