Tuesday, October 22, 2013

temperature illusions, temperature perception and touch receptor science

A couple of fun ways to explore our bodies' temperature (heat & cold receptors) and touch receptors.  

Hot or Cold?

Place one hand in a bowl of warm water and the other in cold water, holding them there until you are no longer aware of the warmth or coldness.  

Then dip your hands in a bowl of room water temperature.  What happens?  

The hand that was in the warm water will perceive the room temperature water as cool and the hand coming from the cold water will perceive it as warm.  

Why this happens: Your heat and cold receptors adapted to the temperature of the water they were in. This shows us that the sensation of warmth or coldness is largely determined by the temperature you have already adapted to.

Cool Fooler

Take 3 pennies.  Place 2 in the fridge and the other you hold tightly in your hand until it is the same temperature of your skin, about 5 minutes.  

Next and you have to do it QUICKLY removed the cold pennies placing them 3 in a row with the warm penny in the middle.  Using the first three fingers of one hand press a finger down on each penny and hold for a moment.  (?) What temperature is perceived by the middle finger?  (this works best if the person pressing down on the pennies doesn’t know which penny is in the middle.)  

The answer is: The finger in the middle perceives the penny as cold! WHY?

Because the messages from your heat and cold receptors are being overridden by your pressure receptors.  Your brain is making an assumptions that the temperature stimulation coming from the same place as a pressure stimulation is sending all the same messages.  This is possible because your sense of pressure is more accurate than your temperate sense! 

Both of these fun experiments came from the book See For Yourself More Than 100 Experiments For Science Fairs and Projects by Vicki Cobb

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