An Experiment on Quantitating Action Potentials for Toothpick and Wind-Blowing
Quantitating action potentials To quantitate the detection of an action potential for toothpick and wind-blowing, you could first record the sound that the speaker emits when connected to the cockroach in a controlled setting (room temperature, no moving air, no change in the lights, etc). Then, you would touch the toothpick to the cockroach and also record the sound. To increase the accuracy, you could record multiple touches of the toothpick to the same place on the cockroach. You would then take the recorded sound waves and graph them. To determine if an action potential was detected, you could measure one of two things.
First, you could measure the amplitude of the sound waves in the background recording versus the toothpick touching (since this would indicate volume), and see if there was a significant difference between the two. You could also count the frequency of the sound waves per minute to see if the toothpick touching significantly increased the number of sound waves. To quantitate wind-blowing, you would repeat the above experiment but instead of recording the sound from the toothpick you would record the sound the speaker emits when you blow on the cockroach. To quantitate the strength of the response when an action potential is triggered, you would first set up the cockroach as we did in the second part of the experiment.
Then, you would select several different genres of music, such as heavy metal, classical, and pop, and sample a few songs from each category. Underneath and alongside the cockroach leg, you would place a ruler or other measuring device. You would play each song and record the distance in millimeters every time the cockroach leg moves. You’d average these values and determine if there was a significant difference in the amount the cockroach leg moves when connected to different types of music. Experimental controls During the experiment, you would want to be sure to keep the background noise constant (no talking or background music playing), prevent any air currents other than the controlled blows, and keep the same amount of light and heat in the room during the trials. A negative control would be recording the sound waves of the noise that’s produced when you don’t blow on the cockroach or touch it.
A positive control would be hooking the speaker to a live cockroach that you know is firing action potentials when it moves its leg and recording the resulting sound waves. This control might be problematic for ethical reasons, however. If you were trying to determine what kind of music elicits more or greater action potentials, a negative control would be again recording the sound waves that the speaker emits when you aren’t playing any song. A positive control would be playing a song you know would elicit more action potentials, such as one that is significantly louder. Otherwise, you would want to select songs from each genre that have similar characteristics, like volume, beats per minute, types of instruments, etc. Predicted outcomes For the first experiment, I would expect that the control (no touching) would result in a small number of quieter sound waves with a low amplitude.
The sound waves that result from the toothpick I would expect to have a higher amplitude, and for there to be more of them. I would expect the same for the wind blow, except the difference compared to the control might not be so pronounced simply because there is less direct contact. For the second experiment, I would predict that the leg would move the greatest number of millimeters when louder and more intense music is played, such as heavy metal. The consistency and volume of the loud music would cause the leg to move the most since it most likely would trigger stronger and more action potentials. Other music, like pop and classical, would cause the leg to move even less. The control test, or the sound waves when no music at all is played, would most likely result in no leg movement at all.