Tuesday

Raven sets five objects on the Windowsill: a mirror, a bell, a lemon, a cotton ball and a cold spoon.

"One object per sense," she says. "What do you notice? Each one needs a different part of you."

Rocket rings the bell. "Ears." He looks in the mirror. "Eyes." He taps the lemon. "Nose, and tongue, but not today."

He touches the cold spoon to the back of his hand. "Skin. Cold and smooth at the same time."

"Taste you only get to think about today," Raven says. "The lemon stays on the sill."

Nova hovers over the row. "Five organs, five kinds of receptors," she says. "One brain reading all of them."

Vision occurs when light is processed by your eye and interpreted by your brain.

Light passes through the clear cornea, then the pupil, the opening to the inside of the eye. The pupil grows or shrinks to control how much light enters.

The lens focuses the light on the retina at the back of the eye. The retina converts light energy into a nerve signal.

The optic nerve carries that signal to the brain, where it is interpreted.

Your ears have two jobs: hearing and keeping your balance. Hearing happens after sound vibrations cross the eardrum to the inner ear.

There the vibrations are changed into nerve signals and carried to the brain by the auditory nerve.

The sense of smell begins at the nerve endings high in the lining of the nose. Smell and taste work together, and most tastes are linked with odors.

You have about 10,000 taste buds. They sense sweet, salty, sour, bitter and umami flavors.

The sense of touch makes you aware of pain, temperature, pressure, vibration and body position.

Skin, muscles, tendons, joints and internal organs have nerve endings, called receptors, that detect these sensations.

Your brain interprets the type and amount of touch. It also decides whether the sensation is pleasant, unpleasant or neutral.

Strong work. Tomorrow is Windowsill Lab: a ruler-drop reaction test and a ten-object memory game.