People experience and explore the world through their senses. In fact, as children, the human body solely relies on experience and sensory stimuli to learn about the world around them. In most people’s lives, their senses work together to teach them about their surroundings. However, what happens when your senses start contradicting each other?

You’ve probably experienced something similar before. Sometimes, senses clash — and it leaves the mind confused. Funny and curious, this fascinating phenomenon would make for an intriguing science fair entry.

People’s senses can be surprisingly easy to fool: apples can look like apples, but they can taste like bananas. This may sound odd, but science can play tricks on our senses. This phenomenon is explainable through the ways our sensory systems. Noses and tongues are especially easy to manipulate. These body parts can easily be manipulated into receiving contrasting stimuli, lighting a fire for the battle of the senses.

One prominent scenario is when you experience a stuffy nose. Stuffy noses are one of the instances where you might notice that the scent of the food contributes to how things taste. Imagine eating some strawberries but, at the same time, smelling heavy and strong banana scents. Which sense do you think contributes more to how the fruit will taste? Does the banana scent overpower the strawberry flavor? Studying this curious occurrence will take you through the interesting phenomenon of the battle of the senses.

Project Summary

Science is everywhere. It’s in the house, the school, and everything people do. But one of the most frequent exhibitions of science people have fun with is their experience with food. This project will require some volunteers who will contribute to the study by sharing their experiences.

This project is an entry under food science, an intermediate-level activity that you will surely enjoy executing for the science fair. Make sure you familiarize yourself with the guidelines and rules your science fair has about human volunteers.

This science project will take one to two weeks to finish and will likely cost you about under a hundred dollars to execute. The concept of this science fair project is inspired by Dr. Svenja Lohner‘s work online, seeking to inquire into the effect of scents on taste, exploring the comparison between gustatory and olfactory stimuli and their influence on food and flavor.

Introduction

To understand what concepts you’re looking into, you dive into what elements influence flavor. This science fair project explores how people perceive taste and scents, how these two sensory stimuli interact, and the many curious things these two are responsible for.

What is Flavor?

Contrary to misconception, flavor isn’t something as simple as taste, although they are casually used synonymously. The definition of flavor, in science, culinary technicalities, and gastronomical studies is not something arbitrary or vague. It is a precise and technical concept that describes the combination of gustatory and olfactory stimuli.

Scientifically, professionals define flavor as the sensory impression of food or other substances primarily through the chemical senses of taste and smell. The tongue and the nose, respectively, connect these senses to the brain, sending messages to the organ through external input received by the nerves or sensory receptors.

The tongue is able to determine the many basic tastes. The most prominent tastes, however, are bitter, salty, sweet, sour, and umami. These tastes, in conjunction with the aromas and scents detected by the nose through its olfactory receptors, determine flavor.

Flavor is the experience of the intermingling of aroma and taste. However, it is also important to note that flavor also considers the texture of food as the mouth reacts to the sensation food or substances deliver.

The Tongue and Tastes

If you have a favorite food, you are able to enjoy it through the organ called the tongue. The tongue is an organ primarily responsible for detecting gustatory stimuli or taste. It is a part of the digestive system and facilitates the movement of food as you eat. It assists people in chewing, eating, and other important processes like speaking.

You may already know this, but the tongue is a muscle. To be completely accurate, the tongue is a group of muscles. The tongue consists of many different muscles that work together to do its job, contributing to important bodily processes through digestion and communication.

In the context of this project, however, you focus on the tongue’s ability to recognize taste and the factors that influence people’s perception of taste. The tongue, through nerves and sensory receptors, introduces taste to people and their brains.

Tastes are gustatory stimuli created by the elements that come in contact with the nerve endings on tongues. Tastebuds receive these elements as they come in contact with the tongue, testing the things people eat and drink. These tastebuds house receptors that remember the chemical substances that create tastes.

The Tastebud and Sensory Receptors

The taste receptors that recognize tastes are located in the taste buds on the tongue. Arranged like orange-fruit sections around a fluid-filled funnel, the chemical substances wash into these funnels and provide sensory input that becomes taste.

Microscopic hairs called the microvilli also help people process taste. These tiny hairs send messages to the brain. The brain then interprets these messages and signals that help identify tastes for the body.

Taste is an important stimulus, as it helps people recognize harmful substances. The sense of taste is vital to people’s survival, as it serves as a warning system of sorts. It helps people recognize good and poisonous food.

Identifying and recognizing tastes is your brain’s way of keeping you safe. It allows you to figure out what you have in your mouth. Have you ever experienced accidentally drinking milk that had turned sour? As the bad milk comes in contact with the taste buds, your brain starts to process what’s in your mouth and instantly recognizes it’s spoilt milk. The brain probably goes, “this is milk – but it kind of tastes funny; you might want to spit it out.”

As your brain gets a clear idea of the messages your tongue is sending to it, it starts to recognize that it’s dangerous, warning you about the problem. However, you may notice that certain things or circumstances dull your sense of taste. Cold food and drinks often mess with people’s ability to taste things. Another more interesting reason, at least in the context of this project, for a dulled sense of taste is a cold or a stuffy nose. This project will help you explore this curious circumstance.

The Nose and Scents

How do we smell things?

This question has been unanswered for most of humanity’s history. Scientists and experts, in fact, had only recently understood the processes at work as people detect scents through their noses.

The nose and the brain work together to process, recognize, and make sense of the many things they constantly detect. Invisible particles, chemicals, and substances float around constantly. The nose detects all these things consistently and remembers each one, allowing people to be familiar with the scents around them and intrigued or surprised by those they don’t remember.

The nose helps people survive, allowing them to recognize and find food. It helps people avoid danger as scents often act as a warning about which substances or chemicals are bad for a person’s health. Noses also help with tasting food. This is why food tastes bland whenever you have a stuffy nose.

Brains process scents very differently from how it processes visual and auditory stimuli. When you see with your eyes, you are able to isolate the things that you see, separating colors and components with your eyes. You are also able to isolate things you hear. When you listen to a band, you can hear the drums separately from the guitars, the bass, and the pianos. In contrast to these instances, the brain often detects mixtures as a single thing, not isolating various parts of the mixture. Coffee smells like coffee, not sugar, cream, and coffee.

The Olfactory Sensors

Inside your nose, up your nostrils, there are tiny sensory receptors called neurons. These neurons constantly communicate with each other, relaying messages to the brain as chemicals in the air come in contact with them.

These receptors are especially good at detecting scents. This is why they’re called olfactory neurons, as they help the process of olfaction or the act of smelling. These neurons act like cables, relaying the message they receive from outside and to the front of the brain called the olfactory bulb. The olfactory then sends the message across the other parts of the brain, giving people an idea of what they’re smelling or detecting.

Olfactory sensors also play a massive part in highlighting flavor. As you put food into your mouth, chemicals called odorants – scents in food and other things – enter your nostrils and contribute to flavor. However, nostrils aren’t the only ways for the nose to detect scents.

The mouth connects with the nasal cavity around people’s throats and allows the olfactory receptors to receive olfactory stimuli from inside the mouth. This is another way how smelling the things you chew — and the food in your mouth — contributes to flavor.

The part of the brain that recognizes scents is also in charge of storing memories and provoking emotions. This is why people often associate memories and emotions with the things they smell.

The Battle of the Senses

As mentioned earlier, a stuffy nose is an impediment to flavor detection. For some reason, food and drinks don’t taste as strong or as sharp as they do whenever you have a cold or a nose that feels stuffed up.

This is because the tongue doesn’t take the sole responsibility for flavor. The tongue can’t take full credit for providing your brain with the signals for flavor. The nose contributes massively to flavor detection, arguably deserving just as much credit for the tastes and flavors you now know. This is your and this project’s objective. To settle the score between the nose and the tongue, this science fair entry seeks to discover which contributes more to flavor recognition.

The nose helps recognize flavor by smelling the food before it enters the mouth. The nose even detects scents as you chew and swallow the food you put in your mouth. In fact, it has been an intriguing phenomenon when the smell of food overpowers the gustatory signals the tongue sends to the brain and alters the flavor in some way. Apples start to taste like bananas, and strawberries can start tasting like lemons.

This activity will explore the many ways scents affect taste and which of the two senses bears a stronger influence over the mind as it recognizes flavor.

The Experiment

This science project takes loose inspiration from the old trick of smelling something stronger before you take a bite out of something else. It’s a classic way of messing with your brain that has been done at school to test the senses.

As an experiment fit for the science fair, this project will provide you with a more systematic way to gather data. The research design will require volunteers, so you may want to call a few friends. Essentially, the experiment will be somewhat similar to the old parlor trick that manipulates the senses but much more organized and systematic.

Surprisingly, professionals and scientists believe that flavor is 80% aroma and 20% taste. This project will put this conclusion to the test. Scientific studies believe that smell is the main determinant of flavor, contrary to what most people believe. This is because taste buds and sensory receptors on the tongue can only detect fundamental tastes, while the nose can detect a wider range of stimuli. These olfactory stimuli serve as a modifier of sorts to the tastes people detect in food, impacting flavor.

Through this science project, you will explore how smell and taste work together to create flavor. You will explore how this connection affects perception. In fact, the connection between these two senses is so strong that people are able to associate certain scents or aromas with flavor. Through this science fair entry, you will be able to test, experiment, and explore how the two senses interact to introduce flavor.

Objectives

Through this experiment, you will be working to answer key questions and concepts regarding the science behind flavor. Here are some of the questions that will guide you through the experiment:

• Why are there differences in the taste of food?
• At what point in the eating process do we start tasting food?
• Which sense is more important to detecting flavor?
• How are the two senses, smelling and tasting, connected?
• What are the other factors that influence the perception of flavor?
• What are the ways to most effectively manipulate flavor?

These questions will guide you towards a better understanding of the machinations behind your senses and the dynamic at work between body parts and substances. The understanding you gain from this subject is relevant discoveries that you can apply in real-life scenarios.

Materials, Equipment, and Resources You Need

There will be quite a number of materials and resources needed for this experiment. Most of these materials and resources can be procured through a quick run to the grocery store, a pharmacy, and some online shopping. Save for the volunteers, the materials and equipment are readily accessible and available in stores.

Here is the complete list of the things you need for the project:

• Molecule-R Aroma E-evolution Kit
• Several Spoons
• Several Mini plastic cups with lids (2 oz)
• Medicine dropper
• Cotton balls
• Blindfold
• Ten different foods
• Glasses of water
• Volunteers
• Cardboard box
• Permanent marker
• Pens or pencils
• Lab notebook

Now don’t be intimidated by the name Molecule-R Aroma E-evolution Kit – it’s not as complex as it sounds. It’s actually just a science kit available in Walmart and other online shops. For the spoons, you’ll need a lot of these as the experiment has to be sanitary and hygienic as possible. Prepare two spoons per food sample per volunteer. This way, a single volunteer has at least two spoons for each sample, ensuring a clean and hygienic experiment.

For the mini plastic cups with lids, you have to prepare a cup for each food and two for each scent. These mini cups are available both online and in physical stores around your proximity. You also have to prepare a lot of cotton balls as you will need two for each scent.

The blindfold can be anything that impedes vision, such as scarves, handkerchiefs, eye masks, or even swim goggles blacked out by some paper. The ten foods can be just about anything, but it’s always recommended to keep it simple. Perhaps stick to fruits, vegetables, sweets, and other simple and readily available and safe food.

Finally, when it comes to volunteers, make sure you follow and observe all science fair guidelines when it comes to dealing with human test subjects, as most committees are very strict with these activities. The recommended number of volunteers is ten, but you can always check a guide to help you decide on the number of volunteers you can have.

Molecule-R Aroma r-Evolution Kit

Buy on: Walmart / Amazon

Perfect for aroma-based activities, the Molecule-R Aroma r-Evolution Kit is an ideal fit for this experiment. It provides you with four aromaforks, 21 different volatile aromas, four molecule-R droppers, and 50 diffusion pastilles. This innovative product by MoleculeR is an excellent resource for multi-sensory experiments for science fairs.

Experiment Proper

The experiment proper has three main parts: the food preparation, the flavor testing, and the analysis. This article will walk you through all these parts to ensure that you produce the best results for the science fair.

Food Preparation

Since this experiment is all about food, one of the most important factors of the methodology is to keep everything fresh. You have two ways to go about this: the first is to prepare the ingredients on the night before the testing and store them in the refrigerator; the second is to prepare everything on the same day. There are pros and cons to both methods, so choose wisely.

If you prepare the food the night before, it is important to remember that food can easily lose flavor when stored for too long. On the other hand, preparing the ingredient on the same day will likely have you work more before the test.

Food-Scent Pairing

Another important aspect of the project is preparing the food and the scent that will work together to manipulate your volunteer’s senses. As mentioned before, it’s always recommended to keep things simple, so here are some pairings that would work well for this experiment:

Food	Scent
Sweet potato	Cinnamon
Strawberry Yogurt	Banana
Banana	Strawberry
Plain applesauce	Cinnamon
Nutella/Chocolate pudding	Mint
Carrot	Butter
Peanut butter	Coconut
Vanilla (yogurt)	Banana
Peanut butter	Vanilla
Mustard	Chocolate

The food stated in the table above is easy to access or purchase, giving you an easier time with procurement and logistics. You can definitely make the changes you wish, but it’s important that you understand the method behind pairing food together.

The most important thing is to remember that when you pair food together, choose two things that have similar textures and temperatures. You will find that these two things help people identify the flavor. To find similarly-textured food, buy the ready-to-eat products in groceries or stores.

Preparing for the Food for the Flavor Test

As you finish deciding on which food and scents to use together, it’s time to organize for the flavor test. Start by putting all the food in separate cups. Make sure that as you fill up each cup, you use a clean spoon to avoid contaminating the taste of the food. Label each cup with a number and keep tabs on which number corresponds to each food through your notebook.

If the foods you prepared for the experiment have different textures, stir the food until they have the same consistency. Additionally, if you intend to do the preparation on the same day as the flavor test, keep all the food at room temperature to avoid loss of taste.

Preparing the Scents for the Flavor Test

Prepare the scents by setting a pair of cotton balls in a mini cup with lids. Put a single drop into the mini cup to capture the aroma within the cotton balls. The cotton should not be too wet, but the smell should still be noticeable. You may adjust the drops needed accordingly. Cover the mini cups with lids to keep the aromas inside, and number the mini cups with a marker. Keep track of the numbers corresponding to each scent by writing them down in your notebook.

Prepare a separate pair of cotton balls and put one drop of tap water on each of them. These cotton balls will serve as control smell samples, which you will use to test the preliminary taste of the food without the influence of a scent. Remember to rinse the droppers you use well to avoid cross-contamination between scents.

Assemble the food in a box, so your volunteers see the food until the flavor test.

Performing the Taste Test

Before you perform the taste test, there are three important things to remember: first, the testing area should be free of any overpowering scents that may distract the volunteers from the experiment, and second, the volunteers must not have any colds or any condition that may impede their ability to smell and taste, and three, the food must be at room temperature when executing the experiment as the cold will reduce the strength of the taste.

You may try the test yourself first so you have a better understanding of the flow of the test and can better explain it to the volunteers. Be sure that when you recruit your volunteers, you disclose the time, the date, and how long the experiment will take.

Final Checks

List out all the flavors and scents on a printout and hand them over to your volunteers; make sure not to label which are scents and which are food, so they don’t know which is which. You may consider doing this alphabetically to avoid grouping the scents and the flavors together.

Prepare a table that will help you record responses and results for each volunteer throughout the test. The table can look like this:

Sample #	Food Sample	Scent Sample	Volunteer Number
1	2	3	4	5	6	7	8	9	10
1	Food 1	Scent 1
2	Food 1	Control
3	Food 2	Scent 2
4	Food 2	Control
5	Food 3	Scent 3
6	Food 3	Control
7	Food 4	Scent 4
8	Food 4	Control
9	Food 5	Scent 5
10	Food 5	Control

As you do the test, fill out the areas where it says Food and Scent with an actual Food or Scent in the experiment. Each sample will have two parts: the flavor test with the food and the scent and another with just the food and the control scent or the cotton ball with the water.

Important Reminders

Throughout the test, randomize the sequence of the food-scent pairing you use on the flavor test, so the volunteers don’t find a pattern in the experiment. Do the experiment with one volunteer in the room at a time to ensure that the others don’t hear the responses. Assign a number to each volunteer so you can present your findings anonymously.

Before you start, prepare an introduction and explanation of the experiment for your volunteer. Let them know that all the food and scents are neither unsafe nor disgusting and that you have taken all the means necessary to ensure sanitation and hygiene. Explain that the experiment is flavor testing, where they will be attempting to identify the flavor blindfolded through the taste and scent of the food they’re about to eat. After they taste the food, they will refer to the list you handed over to them to identify what they had just eaten.

Finally, blindfold the volunteer and only then bring out the box of flavors and scents. Right before you do the actual test, explain the process to the volunteer one more time and perform a dry run with empty spoons and cotton balls. The testing may become confusing at times as they will need to taste and inhale at the same time.

Testing Proper

After the dry run, start with your first volunteer and repeat the steps below until you finish.

• Pick the food-scent pairing from your list and take the samples out of the box. Make sure you use a fresh spoon for each food and each volunteer.
• Ask the volunteer which hand they prefer to eat the food with and immediately let them know not to taste it yet. Let the volunteer know that as they taste the sample, you will be holding up cotton balls near their noses that may or may not contain a certain scent.
• Before they taste the sample, instruct them to exhale, empty their lungs, and not inhale again until you tell them to, you may need to practice this process before the testing starts.
• Once they’re ready, tell them to empty their lungs and hold the cotton balls as close to their nose as possible until the cotton balls touch their nostrils lightly. They should be holding their breath at this point and only inhaling upon instruction.
• Once the cotton balls are in place, you may tell the volunteer to start eating and inhaling. As soon as they start to do so, immediately ask them what flavor comes to mind first. Do not remove the cotton balls yet, as it is important that the cotton balls stay in place until the volunteer swallows the food. You may need to read the list out to them so they can remember and identify what flavor they’re experiencing.
• Proceed to record the results as needed in the table you created.

Before you move on to the next food/scent pairing, cleanse the volunteer’s taste buds with a glass of water and repeat the process. Repeat the process until you have tested all of the food you chose, both with and without a scent (using the cotton ball with water). Remember to use fresh spoons each time you give the volunteers a sample.

After you finish all the samples with one volunteer, thank them and move on to the next volunteer. Remember to use fresh spoons each time.

Analyzing Your Data

Now that you’ve finished your experimentation, there will be a lot of data to observe and analyze. Tally the responses that match the food’s real identity. Analyze whether the volunteer’s responses match the real identity of the more frequently during test samples (with scents) or during control samples (without scents).

Record the total number of correct responses for food samples with extra scents and the number of correct responses in samples where there aren’t any scents. Visualize your findings using graphs to present your data.

You may also count the times when the volunteers identified the scent instead of the food and the times when they both did not match. Extract all possible data from the experiment through an analysis of the responses.

Analyze what your findings tell you about the power of smells over the taste of the food and draw your conclusions. With the results in front of you, who do you think won the battle of the senses? Why do you think this is the case? How could this knowledge help the flavor of food in practice?

What other conclusions can you draw from the data you fathered through the experiment? Was there a particular scent that overpowered all the tastes? Was there a taste that dominated all the other scents? What scents are more powerful than other scents? Did sweet scents dominate the other scents?

Variations

This experiment may yield other variations ranging from food-scent combinations and adding other elements into the equations, such as other factors that may influence flavor. What if you serve your volunteers the same food but with different textures? You may opt for chopped, blended, dried, and many more.

Perhaps explore the concept called phantom aromas. Studies have concluded that ham and beef odors make people think that food is saltier. On the other hand, vanilla scents are automatically associated with sweet things, fooling people into thinking that food has more sugar than there actually is.

Takeaway

This science experiment proves that there is more to what our senses know. Always keep an open mind about the world and approach every inquiry with curiosity. If this experiment interests you, you may want to explore a career in food science, opening doors to becoming a food scientist or technologist, a food science technician, a dietitian or nutritionist, and even a neurologist.

There is much in store for STEM-passionate children. It is their curiosity that pushes humanity forward, opening opportunities for progress and innovation.