Involving a science fair judge may earn a student extra points, but using another volunteer will also work. As part of the presentation, place small pieces of potato, onion and apple on a plate. Blindfold an observer and hold up one piece of food near the volunteer's nose. Place a different type of food in the person's mouth and ask them to identify whether it is an apple, potato or onion. Repeat with all possible combinations. The volunteer's sense of smell should fool the taste sense into believing the food smelled is the food being eaten. Present research and diagrams in the science fair display board explaining the relationship between smell and taste and how they function together to receive more comprehensive data.
An experiment with a ball and an eye patch demonstrates the importance of two working eyes in the proper function of the sight sense. Ask a volunteer to stand 3 feet away from you and toss a soft ball at the person. Record the number of times the ball is caught in 10 throws. Ask the volunteer to remain in the same position and cover one eye with an eye patch. Throw the ball 10 more times and record the number of catches. In the science fair presentation, explain the interdependence of orbital lobes on proper reception of sense information and its influence on depth perception.
Recognizing and classifying items without seeing them might seem like a challenging task, but this experiment proves the brain's ability to interpret data received from the sense of hearing. The experiment requires some assembly prior to the science fair presentation because the student must collect 10 small opaque cans with lids, 12 uncooked pinto beans, 12 buttons, 12 cap erasers, 12 paper clips, 12 thumbtacks and 12 buttons. Place six of each item in a different can and close the lids. At the science fair, present the cans in random order. Ask judges or observers to match the two cans with like objects simply by the sound made when the person shakes the can. After pairing the cans, provide cards with the contents of the cans written on them and ask the volunteer to place the correct label on each pair of cans based on the sound made. Open the cans to confirm how many objects were correctly identified.
An experiment with pantry items demonstrates the importance of using multiple senses to receive the most comprehensive data for processing and interpretation. Prior to the science fair, collect five baby food jars and fill one with salt, another with granulated sugar, the third with powdered sugar, a fourth with cornstarch and the last with sand. Keep the jars covered at the beginning of the presentation and choose a volunteer to assist. Blindfold the person and guide a hand to the jars. Ask the volunteer to feel each substance and tell you what it is based only on touch. Record the responses, and move the jars around. Instruct the person to dampen a fingertip and sample a taste of each substance. The person should tell you what each item is and you should record the responses again. Rotate the jars, and ask the volunteer to shake each jar gently and smell it. Ask if the person can determine anything using the senses of hearing and smelling. Remove the blindfold and ask the volunteer to identify each substance by sight.