Senses Experiment: One or Two?

That because different parts of your body have more — or fewer — touch receptors, sometimes you can't feel everything that's in contact with your skin. For instance, because your touch receptors are far apart on your leg, someone could touch you in two spots, but you only feel it in one.

• A friend
• One paperclip

1. Unbend your paperclip and straighten it out.
2. Form it into a skinny letter "U."
3. Ask your friend to close his or her eyes.
4. Gently press the two points of the "U" on different parts of your friend's skin.
5. Ask your friend how many points he or she feels. Try the forehead, the cheek, the inside of the arm, the back, the calf of the leg. Where does your friend feel both? Where does he or she feel only one — even though there are two?

Your Skin