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Activity

Touch sensing test

Summary: 
With a partner, try and detect how many points of a bent paperclip are touching you, in different regions of your body.
Science content (2016 curriculum): 
Biology: Sensing, Organ Systems (4, 5, 6)
Science topic (2005 curriculum connection): 
Life Science: Human Body (grade 5)
Lessons activity is in: 
Materials: 
  • students in pairs
  • paperclips bent into a U shape
Procedure: 

When you touch something, it makes a neuron fire and sends a message to the sensory part of your brain. Some parts of your skin have more of these neurons packed tighter together, and some have less further apart, so some areas can tell if you touch with two points and some cannot.

In pairs, make a touch tester with an unfolded and bent over paper clip, with about 1cm between points.
One partner closes their eyes and the other touches a part of their skin with either two or one point of the paper clip at a time.
The other partner says if they feel one or two points.
The hands and feet generally can feel if there are two points. The back of the neck does not have touch neurons as closely spaced (fewer cells in the cortex of the brain are dedicated to touch sensitivity), so can often only feel one point.

Show image of homunculus - a man drawn with the size of his body parts scaled to the density of touch neurons they have. Fun to look at, and to induce further experimentation.

Grades tested: 
Gr 3
Gr 4
Gr 5
Teacher: 
Ingrid
Paul An
Teaching site: 
Carnarvon Elementary
ingridscience afterschool
JEMZ+ After school science