Beyond the Book

Imagine your class will be going on a weekend field trip. You will use a campfire for light, cooking, and staying warm. Your class will need to make sure you can get the fire started and keep it burning safely. It’s also important that your group know how to extinguish the fire properly.

As a class, decide which kind of campfire to use: a teepee, log cabin, rakovalkea, or lean-to. Debate the pros and cons of each fire design. Once your group comes to a decision, draw a diagram of your campfire and explain why you selected that design.

With an adult’s help, try foil-wrapped campfire recipes in a fireplace or fire pit. How does the heat from the fire change the taste of different foods?

Campfire Science

FOCUS Book

Campfire Science © Learning A–Z Written by Joe Levit

All rights reserved.

www.sciencea-z.com

Photo Credits: Front cover: © dutourdumonde/iStock/Thinkstock; page 2: © David De Lossy/Digital Vision/Thinkstock; page 3: © Mira Agron/Dreamstime.com; page 4 (left): © Espair/iStock/Thinkstock; page 4 (right): © Frank Cornfield/iStock/Thinkstock; page 5 (left): © Creatas Images/Creatas/Thinkstock; page 5 (right): © Larry Crowe/AP Images; page 8 (left): © Niall Benvie/Alamy; page 8 (right): © Rico Leffanta/Dreamstime.com; icon (used throughout): © DrPAS/iSTock/Thinkstock

Illustration Credits:Pages 6, 7, 9: Signe Nordin/© Learning A–Z

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Thousands of years ago, people made campfires. Fires protected people from predators and biting insects. They made people feel safe. The flames kept people warm and cooked raw meat. The light helped people locate family and friends in the dark.

Today, electricity helps people do many of these things. People live in warm houses for protection. Electricity lights up the night. Stoves and microwaves heat food. And people connect with each other using cell phones and computers. But people still enjoy campfires. When people go camping, they use fire to cook their food and keep warm. A campfire is still a good spot for friends and family to gather and tell stories.

Why We Make Campf i res

Why do people use campfires?

Energy and Matter

FOCUS Question

Campfires provide warmth and light at night.

Campfire Science

Heat Energy • Campfire Science 3 4

Campfire wood has stored energy called potential energy. This type of energy is ready to be used but hasn’t been yet. A ball near the edge of a table also has stored energy. It is ready to roll off but is not moving yet. The potential energy in firewood is called chemical energy. The energy in the wood is stored in its molecules.

Energy itself cannot be created or destroyed. It can only change from one kind to another. When wood burns, its potential energy turns into two other kinds of energy.

The change from one kind of energy to another is called a conversion (kun-VER-zhun). A conversion of energy happens when fire turns wood to ash.

Some of the potential energy in the wood is converted to light energy. That’s why a fire glows! Light energy can help us feel safe on a dark night.

The other type of converted energy given off when wood burns is heat. A fire’s heat is called thermal energy. This kind of energy can keep us warm and cook our food. The heat energy created by a burning campfire dissipates, or spreads out, as the fire burns. The heat warms the cool air around the fire.

After a campfire has burned, the wood’s chemical energy has been released, and the wood has turned to ashes.

Giv ing Off Energy L ight and Heat

This campfire wood has stored, or potential, energy and will burn for a long time once lit.

A burned-out campfire has very little potential energy.

A fire’s potential energy is converted to light and heat energy when it burns.

light light

heat

heat

heat

heat

Heat Energy • Campfire Science 5 6

People use campfire energy to cook food through convection—the movement of heat through the air. People put marshmallows and hot dogs on sticks and hold them over a campfire. The heat energy cooks the food from a distance.

Another way to cook food is through conduction. People wrap baked potatoes or kabobs in foil and place them directly into the fire’s hot embers. The heat transfers directly to the food.

Cooking changes the taste and texture of food. These are chemical changes that cannot be reversed.

Safety is very important when building a campfire, and you should always have an adult’s help. In an open, outdoor place, clear out a large area of all leaves and sticks. Then place rocks in a big circle within the clear area to construct a fire ring.

Next, collect fuel for the campfire. Thin, brittle fuels such as dried grass, pine needles, and bark are called tinder. Tinder helps get the fire started. Kindling goes on top of the tinder. Kindling is made up of sticks about as thick as a pencil. Finally, place fuelwood—branches and logs—on the top.

Get t ing Ready Campf i re Cook ing

A long stick, or skewer, protects your hand from the heat.

Foil protects food from ashes and embers while cooking and traps the heat inside.

branches

fuelwood

kindling

tinder

fire ring

How to Build a safe fire

Heat Energy • Campfire Science 7 8

In a campfire, it matters how the fuel is arranged. Tinder and kindling are placed beneath logs. Flames from these fuels heat the larger logs above. There should be space between the logs for air, or oxygen, to flow. Otherwise, the fire won’t grow.

A teepee fire is named after a Native American structure with a similar shape. Logs are arranged in a cone shape to allow air to flow between them.

Start ing the F i reCampfire Construction

There are several ways to light a campfire. Matches or a lighter will create the flame needed to start the fire. However, it is possible to light a fire even if a flame isn’t available. A glass lens can focus sunlight to create a flame. The flame will burn the tinder quickly. Once there is smoke, a small puff of air will get the fire going.

Friction is another way to create a spark. Friction creates heat. When someone furiously rubs a stick against a piece of wood, it heats the wood. Eventually, nearby tinder may catch fire.

Sunlight shining through glass, or sticks combined with friction, can start a campfire.

Never use gasoline or lighter fluid to start a campfire. They light too quickly and can burn you.

In a log cabin fire, four walls of fuelwood are stacked like a cabin. Then a pile of tinder and kindling is built on the inside. When lit, the fire will spread to the larger logs.

A rakovalkea fire, popular in Finland, is also known as a gap fire. Two long logs are placed one on top of the other. A wedge of wood between the logs allows air to flow through.

In a lean-to fire, sticks are placed at an angle against a large log. The tinder placed underneath the sticks fuels the fire.

Heat Energy • Campfire Science 9 10

At the end of the night, the campfire must be completely put out, or extinguished. Slowly pour water over the embers. Wait until the hissing sound stops. If there is no water around, you can cool the embers by mixing them with sand or soil. The sand limits the oxygen that the fire needs in order to burn.

Do not simply bury the embers. Some of them may remain hot underground. They might touch a tree root or get uncovered by wind. Then a grass fire or forest fire could start after everyone has left. Make sure the embers are cool to the touch before everyone leaves. When done properly, making a campfire can be exciting, useful, fun, and safe.

Write your answers on separate paper. Use details from the text as evidence.

1 The potential energy in a ball can convert to moving energy when it rolls. What does the potential energy in firewood convert to?

2 Describe two examples that demonstrate how convection and conduction can be used to cook food on a campfire.

3 According to the book, in which order should you place wood to build a campfire?A 1. kindling, 2. fuelwood, 3. tinderB 1. fuelwood, 2. kindling, 3. tinderC 1. tinder, 2. kindling, 3. fuelwood

4 Explain how a campfire can be started without a lighter or matches.

5 Why do you think the author says you should never bury a fire to extinguish it?

Put t ing Out the F i re

Why do people use campfires? Use examples from the book to explain how and why people used campfires before there was electricity.

FOCUS Question

How to safelY Put out a CaMPfire

1. Pour water over the fire and hot embers.

2. Stir and cover with dirt.

3. Check for heat. If still warm, repeat steps.