Everything around us needs energy to work.  Cars run on gasoline.  Houses become warm or cold with fossil fuels.  TVs run on electricity.  What do living things run on?  Food, of course.  There are so many kinds of food though!  Carrots, bread, chicken, ice cream . . .  These are a lot different than the gas you put in your car, but it still makes living things move.  What do they all have in common that makes our engines go?  

Our gas does not come from the gas station.  It is not buried under the earth with the oils and natural gases.  In order to find the stuff that makes us go, we have to go to the forest . . . or a park.  That's right, the gas for living things comes from plants!  Photosynthesis is the process that plants use to turn water, sun, and a part of the air into energy they can use.  I would not go stuffing any plants into your mouth just yet.  You might be in for a bitter surprise.

Plants are all energy changing factories.  They are like the gas stations of the world and every other living thing stops at them to fill up.  Of course, plants do not want to be used like gas stations.  They need the energy they get from the sun to grow.  Some of the energy that is made with photosynthesis is stored in the plants.  This kind of stored energy is energy stored in something that can be used later, like sugar.  This is what living things keep inside of them to use later on.  So really, eating a plant is kind of like taking all of the gas that it stored for later.

Sugarcane goes through a lot of steps before it gets to your table.

Sriramk750 at English Wikipedia, Public domain, via Wikimedia Commons

What does a living thing's body do with this stolen gas . . .  I mean, energy?  Why, fills its own gas tank, of course.  Carbohydrates are an important kind of stored energy that many living things use to stay alive.  The sugar in your kitchen is a type of carbohydrate!  You will find them in anything from cookies to carrots, from Snickers to spinach, from Pop Rocks to potatoes.  Your body, a plant, and the cells of a single celled organism all will break these down for energy.

Now wait a minute, carrots have sugar?

Kander, Public domain, via Wikimedia Commons

These come in many different shapes and sizes.  All of them can be broken down by living things for energy.  Most of the time, when we use the word sugar, we are talking about that sweet, white stuff.  When it comes to living things, sugar is the stuff that your cells use to stay alive.  Glucose is a sugar that we can get by breaking down carbohydrates and our cells use this sugar to get the energy they need.  It's one of the things that all of these foods break down into.  Your mouth loves the taste because it means more stored energy for your body!  Just do not eat too much.  You do not want your gas tank or your body to get so heavy, you cannot carry it around.

Sugar Beet, not as well known as sugarcane, but just as sweet.

The energy in a living thing does not come from a gas station.  It comes from plants, which they made to store energy for a rainy day.  You can get this energy by eating carbohydrates, the gas that makes your body go.  While you need carbohydrates to live, you can have too many or ones that are bad for you, like the white sugar that comes in candy.  So go out and fill up with the many different plant stations.  But leave enough for the rest of the earth, and try not to burst your gas tank.

References:

Chem 4 Kids.  "Sweet, Sweet Carbs"  Chem 4 Kids, 2010.  <http://www.chem4kids.com/files/bio_carbos.html>

Mayo Clinic.  "Kids and Sugar -- the Good, the Bad, and the Ugly"  Mayo Clinic, 2012. <http://www.mayoclinic.org/healthy-living/nutrition-and-healthy-eating/expert-blog/kids-and-sugar/bgp-20056149>

Kids Health.  "Carbohydrates, Sugar, and Your Child"  Kids Health, 2012.  <http://kidshealth.org/parent/growth/feeding/sugar.html>