This lesson introduces how the brain collects information about our surroundings. Our sense of touch is mediated by sensory receptors all over our skin. Different parts of our skin need to be more sensitive to touch than others - the most sensitive parts of our skin have more touch receptors than the ones that are less sensitive. We can measure this sensitivity ourselves using our two point discriminator calipers. This activity allows the kids to think about which parts might be more or less sensitive and form hypotheses that they can test on the spot.