Isabel He

Independent Lab

Investigation question: What is the relationship between the tension of a string and the frequency?

Hypothesis: If the tension of the string increases as I add weight to the strings, then the frequency of the string will increase.

Independent variable: Tension in the string, will be increasing the tension by adding weight to the string.

Dependent Variable: The frequency of the string

Controlled Variable: The length of the string, the placement of the two plots, and the weight differences between the two plots.

Units

Weights will be measured in grams

HZ for the frequency of the string

Materials needed:

Strings x 1 ROLL

flat surface to work at

Weights X 2 pack *note: you will need weights for 20g, 50g, 100g, and 200g.*

Pulleys x2

Meter stick

Frequency detector app ( Recommended: Spectrum)

Procedure:

Set up the experiment as shown in diagram 2

each pulley has to be 40 cm apart, and a 80cm string

apply weights to each end of the strings equally

gently place the string with the weights on the wheel of pulley

check if you can hear a sound made by the string, if not add more weight.

use frequency app and collect data, make sure the room is quiet when you do so.

Clean up lab when finished

Range of Data collection: I will be increasing the tension of the strings for 6 separate times, and each time I would be doing 4 trails after increasing the tension.

Range of data – 120HZ- 460HZ

Key terms:

Tension: The definition given on tension is the state of being stretched tight,

Frequency: frequency is defined as the rate at which something occurs or is repeated over a particular period of time or in a given sample.

Pulley: a tool that would be used to stable the strings as I add more weight to it.

Background Information

The question I will be investigating would be the relationship between the tension of a string and its frequency. My investigation question is what is the relationship between the tension of a string and the frequency? This investigation will allow me to know if the frequency of how a string works would change if I increase the tension of the string. The first part of my research ops my question would be defining the key words and key terms. The two key words of this lab would be tension and frequency. The definition given on tension is the state of being stretched tight. For example in this experiment that i will be doing, I am trying to find if the frequency of the string would change if I increase the tension of the strings. In order for me the increase the tension of the strings, I would be adding weights to each side of the strings which would make the strings tension tighter. The wave I would be finding is a standing wave, also known as a stationary wave, is a wave that remains in a constant position. The way the lab works to find the frequency of the lab is when the medium travels to the opposite direction to the wave, it will be able to show am example of two waves traveling in opposite directions interference. (Standing Waves, July 2015). Frequency is the second key term of the lab, and is also my dependent variable for this experiment., which is defined as the rate at which something occurs or is repeated over a particular period of time or in a given sample. The second part of this research is for me to define what is it that I am looking for. The velocity of a traveling wave in a stretched string is determined by the tension and the mass per unit length of the string. When the string is vibrating, it will produces a sound whose frequency in most cases is constant. (Strings, Pulleys, and inclines, December 27, 2016) Therefore, since frequency characterizes the pitch, the sound produced is a constant note. Through out some research, I am predicting that the frequency of the string goes up a little bit when you increase the tension. Through out my research, according to the concepts of Newton’s second law and spring mass damper system, a stiffer system will have a higher frequency as it can produce more force resulting in more acceleration per unit displacement..Therefore, if you increase the tension in the string, the frequency of the vibration increases. The stiffer system of the strings would be when I increase the tension of the strings. The third part of my research will be defining my independent, dependent, and controlled variable. These three variables would play a key part to my research because it will tell me what I am changing and what I am finding. For this project my independent variable is the tension in the string, and I will be increasing the tension by adding weight to the string. The dependent variable is what I am looking for, which is the frequency of the string. My hypothesis for this project is If the tension of the string increases as I add weight to the strings, then the frequency of the string will increase. This hypothesis would help me focus on what I need to find through out this research, which is how much the frequency would change as I increase the tension of the strings. As mentioned in the hypothesis, I would be increasing the tension of the string by adding weights. For this lab, the data I will be collecting is predicted to be from a range of 120 HZ to 460 Hz ( Vibrating Strings, February 7th 2014)