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In my experiment, I will be testing how effective the pinky is at estimating the temperature of water. I was wondering how many sensor cells there are in the human pinky?

I recently did some research on how the brain gets these sensory details from the skin and found that the part of the brain that receives these signals is called the Hypothalamus. Where in the brain is the Hypothalamus and how large is it in comparative size to the rest of the brain.?

What is the rate of temperature increase or decrease to room temperature for water that I should use in my experiment?

When using statistical analysis, what is the most effective way to have realistic numbers?

I plan on using set ranges of temperatures for people to estimate the temperatures for. I am going to tell them what these ranges are; just that they are hot, room temperature, and cold. I plan on having the cold at around 30-40 degrees, the room temperature from 60-75, and the hot at 100-110. Do you think this is a good idea or should I just have a set temperature for each section of the test?

Thanks for answering these questions for my Science Fair Project

Question Date: 2012-12-18
Answer 1:

There are a couple thousand nerve endings per cm2 in the finger. The hypothalamus regulates body temperature, but it is the primary somatosensory cortex which receives sensory information from nerve endings such as thermoreceptor. The somatosensory cortex is in the postcentral gyrus which is a ridge located at about mid brain.

1. You should test different rates of temperature change to see how this effects your results. There is an old anecdote about how if you put a frog in a pot of boiling water it will jump out, but if you put a frog in cold water and very slowly heat it, you can cook the frog with out it ever jumping out. I have never heard of this actually being tested (and I do not recommend testing it) but the rate of temperature increase should definitely play a role in your experiment.

2. In order to show that you have a statistically significant result you need to have a sufficient sample size (i.e do many repeats of the same experiment), and you need to have sufficient controls. Try to control for other external variables by testing multiple people. Controlling for the way you administer the experiment by doing it the same each time. Give the people the exact same instructions so you do not biased them, etc.

3. I would not tell them anything about the temperatures. Just tell them that you have three different temperatures and that they need to guess the temperature of exact. This way you would limit the amount to which you bias them by telling which is "hot" "cold" or "medium". Just make sure you use appropriate temperatures so that you do not harm any subjects. Additionally, one thing you may want to consider is the order by which they test the temperature. In other words, do you get different results if they go hot=>warm=>cold vs cold=>warm=>hot or any other order?

Hope this is helpful and good luck with your experiments!

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