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Hi, there!  Squeaks and I are cooking a big meal to share with our friends, and that got us thinking about the science of food, and also the science of how we eat, so while we cook, we thought you might enjoy these videos about food and eating.  Let's start off by watching this one about the five food groups.

Our bodies need lots of energy to keep us going throughout the day, and do you know where we get that energy?  That's right, from the food we eat, and all kinds of different people enjoy different kinds of food, but whether your favorite meal includes noodles or nectarines, tortillas or tofu, most types of food have some of what our bodies need to stay healthy.  

You might already know that we can put different kinds of food into different groups.  We call these, you guessed it, food groups.  But let's check out each group and see what kind of food belongs where.  Let's start with the fruit group.  You gotta love sweet delicious fruit.  This group includes things like apples and pears, oranges, and strawberries.  Fresh fruit is the best for you, but fruit that's canned or frozen counts too.  After all, many fruits are hard to find in the winter and some fruits only grow in certain parts of the world, but don't forget about fruit that's been dried.  Raisins are just dried grapes, and prunes are dried up plums, and even juice is part of the fruit group, but only if it's all fruit juice and doesn't have added sugar.  

Next comes the grain group.  Grains are plants like oats, wheat, and barley.  If a food is made from one of these plants or any other grain plant, it belongs here.  That means things made of flower, like bread and noodles, breakfast foods like oatmeal and cereal, and even rice are all part of this group.  

Next up, the vegetable group.  I bet you already figured out what goes here. Vegetables come from plants, too, but unlike grains, they're either the roots, stems, or leaves of certain plants that we can eat.  Carrots, for example, are the sweet orange roots of the carrot plant.  A head of lettuce is just a bunch of crunchy leaves, and asparagus is actually a stem of the tasty asparagus plant.  

There are so many kinds of veggies out there that we can actually split this group into smaller groups.  For example, there are dark green veggies like spinach and starchy vegetables like potatoes and sweet potatoes.  Then, there are red and orange veggies like beets and carrots, just to name a few.  Now, what other foods can you think of?  

What about the stuff that's inside your sandwich?  Meats like chicken or hamburger belong to the protein group, and so do fish like tuna and eggs made any way you like.  But not all members of this group come from animals.  Other foods like beans, peanut butter, and tofu, which is made from soybeans, are full of protein, so they're also proud members of the protein group.

And that leaves us with the last food group: dairy.  If a food is made from cow milk or soy milk, it's in the dairy group.  So this is where you find things like yogurt and all kinds of cheeses, as well as your usual glass of milk.  And do you know what else fits in this group?  Ice cream.  

But that reminds me, sweet treats like candy don't fit into any of our groups.  That's because they're made of mostly sugar and don't have any of the things that our bodies need to stay healthy.  So it's okay to enjoy these foods from time to time, but just not a lot of the time.  

Now, do you think you can put a food into the right group.  Let's take a tasty food quiz and see how well we know our food groups.  We'll start with a slice of pineapple.  What group do you think it goes in?  Squeaks says the fruit group.  Good job, Squeaks!  Yes, pineapple belongs in the fruit group.  What about this hard boiled egg?  What group do you think this fits into?  That's right, the protein group.  Eggs are a good source of protein.  Here's one more.  We'll end our game with a food that fits into two groups.  Macaroni and cheese.  Let's look at each part separately.  The cheese from the mac and cheese fits into the dairy group because it's made from milk.  But what about the macaroni noodles?  Well, we learned earlier that noodles are made of flour from grain, so that means macaroni belongs to the grain group.  

That's right!  Macaroni and cheese contains foods that are in the dairy group and the grain group.  Whoo.  All this guessing has made me hungry.  Hey, Squeaks, let's make a snack, and remember, the next time you're hungry and head to the pantry or fridge, choose something healthy and see if you can guess what group your food fits into.

So we have the turkey in the oven right now.  Which food group do you think turkey is in?  That's right, turkey is in the protein group.  But fruits and vegetables can be more complicated.  How do we tell the difference between a fruit and a vegetable?  Let's watch this video and find out.

Taking care of our plants at the fort is one of favorite things to do and the best part is, sometimes we can eat what we grow.  We grow lots of plants, including vegetables like lettuce and carrots and fruits like blueberries and tomatoes.  Yeah, you heard me right, according to scientists who study plants called botanists, both blueberries and tomatoes are actually kinds of fruits, even though a lot of people call tomatoes vegetables. 

But how do we know the difference between fruits and vegetables?  It can be tricky, but if we learn a little bit about how plants grow, we can make a pretty good guess.  So let's start with how plants start: seeds.  When a young new plant begins to grow from a seed, it pushes its roots deep into the soil and stretches its stem and leaves up towards the sun.  Sometimes the roots, stems, leaves, and flower buds of a plant are edible, which means we can eat them safely, and we call of these edible plant parts, including unopened flowers, roots, stems, and leaves vegetables.  Check out this popular favorite: the carrot.  If you look at a carrot as it's growing, you can see its leaves and stem grow above the soil, but the part that we usually eat grows down in the ground.  That's right, the carrot is a root, and since it's a root that we can eat, it's a vegetable.  Alright, now, what about fruit?  The fact is, every fruit starts with a pretty blooming flower.  Flowers not only look and smell nice, they also do something really important for the plants that make them: they help plants reproduce.  

When a living thing reproduces, it makes more of itself and plants that make flowers reproduce by making seeds.  In flowering plants, a seed starts to form in a special part of a flower which begins to swell as a seed gets bigger.  A lot of the time, this part of the plant keeps growing around the seed to protect it.  Eventually, the flower falls off, and the swollen part of the plant that's left behind becomes what you and I know as a fruit.  So if it's an edible plant part like a root, stem, leaf, or unopened flower bud, it's a vegetable.  If it's part of a flowering plant that has a seed in it, it's a fruit.  So, do you think you can guess whether what we're growing in the greenhouse is a fruit or a vegetable?  Let's go for it.

We'll start with a delicious plant that's super good for you: spinach.  What do you think spinach is, a fruit or a vegetable?  A vegetable is right.  Spinach is a leaf.  If we take a look at the spinach plant, we can see that it has roots to hold it in the ground and that its leaves are held up by a stem.  Good job.  How about a cucumber?  What do you think, fruit or vegetable?  Right, a fruit.  If we look at a cucumber plant, we see it has roots, stems, and leaves, but those aren't the parts we eat.  Cucumbers also make flowers.  It's that special part of a flower that becomes the cucumber fruit.  If we look inside a cucumber that's been cut, we can see its little seeds.  Let's try one more.  How about green peas?  Fruit or vegetable?  Believe it or not, peas are a fruit.  Pea plants make flowers and parts of these flowers become the fruit that we call a pea pod.  If we eat the peas in the pod, we're actually just eating the pea seeds.  Now, sometimes it's hard to tell what something is in a supermarket.  Sometimes we grow fruits that don't have seeds, or have seeds that are too small to see.  It can also be tricky to tell if something's a root, stem, or a leaf, but it's always fun to see if you can guess what in your shopping cart and what's a vegetable.

Just make sure you eat plenty of both.  Mm, all this talk about food is making me excited to taste our dinner, but do you know how we taste?   Well, let's watch this video and learn all about our tongues.

What's your favorite flavor of ice cream.  I'm all about mint chocolate chip and Squeaks is crazy for strawberry.  Even though I have a favorite flavor, I love getting to try new ones.  Isn't it great that we get to enjoy so many different tastes?  From ice cream to beets, from peanut butter and sardine sandwiches to bananas and peaches, there are just so many different tastes to taste, but taste doesn't just help us figure out which flavor of ice cream is our favorite.  It also helps us tell if food is good or dangerous to eat.

If we get a mouthful of spoiled milk, it'll taste gross.  The icky taste will tell us to spit it out instead of swallowing it, which could make us sick.  So how do we taste tastes?  Well, if you ever licked an ice cream cone, you know that the tongue is an important part.  Your tongue is actually a muscle like the muscles in your arms and legs that help you move, but it's a special muscle that can detect temperatures, textures, as well as how oily or chewy something might be, and of course, flavors, and there are at least five main flavors that your tongue can taste: sweet, sour, salty, bitter, and umami, which is sort of a rich, savory flavor.  Together, these five flavors in different amounts and combinations make all of the tastes that we can taste.  

So how does the tongue do it?  Well, open your mouth and take a look.  Your tongue is covered in small bumps that you can see and feel.  These are called papillae.  Those bumps are where you'll find the most important part of tasting, taste buds.  Taste buds are much, much smaller than papillae, too small to see.  They sit in the grooves and on the walls of those bumps, and each papilla can have many taste buds.  Even though they're super small, these little buds are where taste begins.  Each taste bud is shaped like a teeny tiny pocket filled with even smaller little things, long thin strands called taste hairs.  

These hairs sit at the top of the taste bud where tiny pieces of food can wander in when you eat.  The taste hairs are how your taste buds sense the flavor of the food.  Once they come in contact with a food, they turn the taste of that food into a signal.  The signal then gets sent to your brain telling it what you're tasting.  Some taste buds can only sense one flavor, while others can sense all the flavors, although some more strongly than others.  So you can only understand the flavor of your food once your brain has gotten signals from lots and lots of different taste buds.  Now, you might have heard that different parts of the tongue are sensitive to different tastes, but that's not true.  All five flavors can be detected equally well around the tongue, but the sides of the tongue are much more sensitive than the middle.  That's something to remember when you're licking your next ice cream cone.  Try tasting it with the tip of your tongue or the sides instead of the very middle and you could get a stronger sense of the flavor, but your tongue isn't the whole story when you're talking about taste.

Have you ever eaten a meal when you have a stuffy nose?  Then you probably noticed that smell is an important part of getting the flavor of food, too.  As you eat, some of the chemicals from your food make their way up into your nose.  There, you have different kinds of cells that can sense them and send signals to your brain.  So the taste buds on your tongue and the smell signalers in your nose work together to tell your brain all about the food you're eating.  So the next time you're licking an ice cream cone or snacking on a sandwich, why not take a moment to appreciate your buddies in flavor: your taste buds.  Without them, nothing would taste, well, like anything.

Ooh, maybe we should have ice cream for dessert, or maybe a big bowl of strawberries or a cookie.  What kinds of sweets do you like to eat?  Why do you think our sweets taste so sweet?  Here's a video about where sugar comes from.

Do you like to eat a sweet treat every now and then?  I know I do, and a lot of us enjoy a cookie or a piece of candy when it's time for that special goodie, and what's a birthday without a cake?  But as much as we might like special snacks like these, we know they're not very good for us, right?  

Fortunately, there are lots of healthier choices out there for when we want something sweet to eat.  Foods like apples and bananas are full of things that are good for our bodies and they're also naturally sweet.  The reason that both desserts and fruits taste so sweet is thanks to sugar.  So where does all that tasty sugar come from?  Believe or not, the story of sugar starts with the sun.  Green plants catch the light from the sun and then take the energy in the sunlight and use it with other materials in the air and water to make a kind of sugar called glucose.  Plants use this glucose as a source of energy to help them grow.  Then, when animals, including people like us, eat plants, our bodies use the glucose in the plants for our own energy, to grow and play.  Aw, thanks, plants.  And glucose is just one kind of sugar that comes from plants.

The sugar that's probably in the canisters in your kitchen is another kind of sweet stuff made by plants, called sucrose.  Plants move sucrose around from one part of a plant to another in a liquid called sap.  You might already know that we collect sap from maple trees.  If you cook the sap for a really long time until most of the water in the sap is gone, then the sweet stuff that's left behind is what we call maple syrup, but maple trees are just one plant that we use to get sugar.  Most of the sucrose we eat comes from a plant called sugarcane.  Sugarcane grows in places where it's warm all year round, and it's related to the grass that grows in our lawns.  Its long thick stems are full of sugar and when the cane is cut down, the stems can be squeezed until all of the sap or juice comes out.  We also get sucrose from another plant called a sugar beet.  Instead of getting sap from the stem, though, we can crush, cook, and squeeze the root of the sugar beet to get its sweet juice.  All of these plants make and store a lot of sucrose, so we use them to make the sugar that fills our sugar bowls, but how does it get from the plants and into your bowl?

The sugar you eat is made by taking the sap from sugarcane or the juice from sugar beets and then heating it until the water in the juice is gone.

As it dries, the particles that make up sugar stick to each other, making little tiny squares that eventually form sweet little crystals.  So whether it's maple syrup for your pancakes or sprinkles for your sugar cookies or even a sweet juicy strawberry, the sugar that you eat comes from plants, and you know what the sweetest part of many plants is?  Fruit!  Lots of plants store a bunch of sugar inside their fruits, but unlike those sticky desserts, fruit also carries a lot of other good things that your body needs to stay healthy.  

Dessert is usually the last part of a meal, but since we're talking about the science of cooking and how we eat, we have one more video to share about something that sometimes comes after a meal.  Why do we burp?  

It happens to everyone.  You're just finishing up your lunch, maybe helping everyone clean up, and just as you open your mouth to say something, oh jeez, excuse yourself, Squeaks.  Burping can be embarrassing sometimes, but everyone does it and people aren't the onlly animals that burp.  Dogs, sheep, and cows all burp after they eat, even though you never hear them say excuse me, and since we all seem to do it, there must be a pretty good reason for burping, and there is.  But to find out why we burp, we first need to learn a little bit about our body's digestive system.  

The job of your digestive system is to break down or digest everything that you eat so that your body can use all of the good nutrients and energy that are in your food.  The digestive system is made of lots of different body parts.  Some of those parts you can see in a mirror, like your teeth and your tongue, and some are deep inside your belly, like your stomach, and between your mouth and your stomach is a long tube called the esophagus.  When you swallow, food travels through your mouth and throat and then moves down your esophagus and into your stomach.  You can think of your stomach a little bit like a pouch or a bag, just like a backpack or a purse, it can stretch a little bit when you put things in it, but there's only so much room in there.  So if things start to get too crowded, something's gotta go, and burping is your body's way of getting rid of extra gas in your stomach when there's just too much of it.

During a burp, gas leaves your stomach and goes up through your esophagus and leaves your body through your mouth and nose and I'm sure you've noticed there's usually a noise involved, but where does all that gas come from?  Well, that depends.  If you've been sipping on soda, then the bubbles from the soda, which are made of a gas called carbon dioxide are to blame for your burps.  But even if you haven't been drinking fizzy drinks, you're still probably going to burp.  It happens to most of us between 6 and 20 times a day.  That's because we swallow a lot of air during the day, mostly without even knowing it.  You might get a mouthful when you stretch your mouth open wide for a yawn, or drink through a straw or from a water bottle or chew gum or eat too fast or if you talk too much while you're eating.  Some foods can give you a case of the burps, too.  This is especially true for foods that, while good for you, can take a while for your body to break down, like beans, peas, broccoli, even bananas.  There are lots of ways that air can end up in your stomach and it all adds up, and once air gets inside of your body, it doesn't have very many ways to get out.  So burping allows your stretched out stomach to get back to normal and back to doing its job: digesting your lunch.  So a case of the burps might not be very pleasant, but sometimes it's just gotta happen.  Just be sure to cover your mouth and you should probably say excuse me, too, okay?

Thank you for watching all these videos with us while we cook!  Do you have a meal that you like to help cook?  Or do you have a favorite food?  Let us know in the comments below or grab a grown-up to help you email us at kids@scishow.com.  Thanks and we'll see you next time.

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