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Project Summary

Difficulty	2  –  3
Time required	Very Short (a day or less)
Prerequisites	None
Material Availability	Readily available
Cost	Average ($50 - $100)
Safety	You should never put your fingers, or anything else, inside a fan.

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Objective

To determine in which direction horses should stand in a cold wind to stay warm.

Introduction

Imagine it's the coldest day of the year, and you're walking outside in a strong wind. In which direction would you rather be walking? Into the wind? Or away from the wind? You might like walking away from the wind better because it's easier to move, since the wind gives a little boost, but which direction keeps you the warmest?

You might not realize it, but whether you're walking outside in a cold wind, sitting in a chair reading an interesting science fair project, or bundled up in your bed, heat is constantly flowing into and out of your body. Heat is also constantly flowing into and out of everything that you see around you. See that tree? Think: Heat flow! See a rock? Think: Heat flow! See an animal, a toothbrush, a piece of celery, a pile of laundry, or a piece of trash? Yep, think heat flow! Heat is everywhere.

Just as a ball always rolls downhill, heat "rolls downhill" too, and flows from an object that is hotter to an object that is colder. If, for instance, you put a cup of hot chocolate in a room-temperature room (and somehow manage to resist drinking it), the heat will flow from the hot chocolate to the room, and from the hot chocolate to the cup, and to the table. The room, the cup, and the table will actually heat up a tiny bit from the heat of the hot chocolate. As the temperature of the hot chocolate gets close to the temperature of the room, the heat flow slows down. When it reaches the temperature of the room, the heat flow between them stops until there is another temperature difference between them. Say, for example, somebody opens the door and lets in a blast of cold air; then the room temperature will drop, and heat will flow once again from the cup to the room until they have an equal temperature again.

Heat flows from a hotter object to a colder object in several different ways:

1. By direct touch (called conduction),
2. On energy waves through open space (called radiation), and
3. By the flow of liquids, like water, or gases, like air (called convection).

If you touch a warm cup of hot chocolate, for example, the heat energy in the cup will flow to the skin on your hands, and your hands will become warmer by conduction.

You don't have to touch something to get heat from it though. If you go stand outside in the sunlight, you are receiving heat by radiation. You are not actually touching the Sun (thankfully), but the Sun's heat energy is flowing from a hotter object (the Sun) to a cooler object (you) on energy waves or rays. In fact, that ray of energy you feel right now left the Sun just 8 1/2 minutes ago and traveled 93 million miles through open space to get to you. What a trip! But the Sun is not the only thing that can radiate heat—everything acts like a little Sun. All the objects that you see around you, including you, are constantly moving heat into and out of themselves, as conditions change, through radiation. It's the reason why warm-blooded animals, including humans, need fur, feathers, fat, or clothing if they want to live in an environment that is cooler than their inside body temperature. Heat is constantly radiating off animal bodies into open space. A lot of food that a warm-blooded animal eats goes toward making heat to help its internal (inside) body temperature remain the same. When it's windy, people and animals lose the heat from their bodies more quickly because of convection. In convection, heat is moved from warm bodies to the air as the wind blows by. It's the same thing that happens when you blow on hot soup. Your breath is like the wind, and as it blows by the soup, it takes some of the heat of the soup with it, so that it cools off faster and you can enjoy eating it.

Heat flow greatly affects the behavior of animals. Warm-blooded animals, like humans, change their behavior in order to try and maintain a constant internal body temperature inside their core, called the core temperature. The core of an apple is the inside part where the seeds are. The core of animals is the inside part, too—deep inside the body and away from the surface of the skin. The core is not inside the hands, feet, arms, legs, or limbs, or anywhere near the skin, because the temperature of those parts can change a lot as the body controls blood flow to them in order to protect the core. The core is actually the part inside the torso of the animal—the part of your body between your neck and bottom, where all the internal organs are, like the heart and liver.

When warm-blooded animals are placed in a cold environment, they will change their behaviors to try and maintain their core temperature. They will do things like:

• Huddle together,
• Fluff up their fur or feathers,
• Shorten their limbs,
• Pull their limbs in close to their bodies,
• Seek out any visible sunlight,
• Seek out a warm rock,
• Curl up in a bed of leaves or brush, and
• Put on clothes (if they are humans, of course).

In this zoology science fair project, you'll figure out in which directions horses should stand in a cold wind to help maintain their core temperature. Remember, wind increases heat loss by convection. So which way is better for the horse to stand? Facing into the wind? Or turned away from the wind? Imagine you're the one standing or walking in the wind—which way is better for you? It's time to put your ideas to the test. If you don't have any toy horses, check around your neighhhh-borhood, and see if your friends have any that you can borrow.

Terms, Concepts and Questions to Start Background Research

• Heat
• Conduction
• Radiation
• Convection
• Warm-blooded animals
• Core temperature

Questions

• What kinds of objects experience heat flow?
• When do objects experience heat flow?
• What are the types of heat flow? How do they differ?
• Why do animals change their behavior in response to heat flow?
• What are some of the ways animals change their behavior when they are hot? When they are cold?

Bibliography

This source describes the three methods of heat transfer (conduction, convection, and radiation):

• Watson, D. (2004). Energy, Heat Flow, and Life. Retrieved June 1, 2009, from http://www.ftexploring.com/energy/heatflow.htm

These sources describe ways in which animals change their behavior in cold weather:

• Science Made Simple. (1995). How Do Animals Spend The Winter? Retrieved June 11, 2009, from http://www.sciencemadesimple.com/animals.html
• Ward, P. (2001). Cool Antarctica. Retrieved June 12, 2009, from http://www.coolantarctica.com/Antarctica%20fact%20file/science/cold_penguins.htm

Materials and Equipment

• Toy horses, large, should be just about equally sized and equally posed (2)
  1. Approximately 3.5 x 12.8 x 12.8 inches
  2. Able to stand upright
  3. With tails made out of flexible material
• Mini paper towels, or regular paper towels, cut to size
• Scissors
• Large bowl
• Tap water
• Hair clips or small binder clips
• Fan, electric
• Room that is free from drafts
• Clock
• Lab notebook
• Adult helper

Experimental Procedure

Notes Before You Begin: Because you are using toy horses—which are not alive, so don't try to keep their core temperature constant—you will not be measuring the temperature of the horses. Instead, you will see how fast heat flow is occurring on the horses by feeling how fast damp paper towels dry on different parts of their bodies. The faster the paper towels are drying, the faster the heat loss by convection. A fan will act as a wind source.

Preparing the Paper Towels

• Fill the bowl about half full with warm water.
• Tear off or cut five sheets of paper towels to approximately 11 x 5 1/2 inches each.
• Fold one of the sheets in half, unfold it, and cut along the fold so that it is split into two pieces. These smaller sheets will be for the horses' heads. The larger sheets will be for the horses' backs and chests.

Figure 1. This photo shows the paper towel sheets that are needed for this science fair project.

4. Put all the sheets inside the bowl of warm water, and gently press down on them until they are completely submerged in the water.

Figure 2. This photo shows the paper towel sheets being gently submerged in water.

5. Remove the sheets together, as a group, from the water and gently squeeze them out over a sink, so that they will all have a similar wetness.
6. Gently un-crumple the sheets and lay them out flat on a surface. The sheets are delicate when they are wet, so might tear. A small tear is not a problem, but if the tear is large, then you should start over and prepare a fresh sheet of paper towel. If you are having trouble opening the paper towels without tearing them, then ask an adult for help.

Figure 3. This photo shows the paper towel sheets being gently unrolled after the water has been squeezed out of them.

Preparing the Horses for Testing

1. Place one of the small paper towels around the first horse's ears, eyes, and snout.
   1. The paper towel should be snug, but not pulled so tightly that it tears.
   2. Clip the paper towel under the horse's chin with a hair clip or a binder clip so that it stays snug.
   3. If you are having trouble getting the paper towel fastened with a clip, ask an adult for help.
2. Place one of the larger paper towels around the first horse's neck and chest, in the same way that you get ready for a hair cut at a barbershop, with a clip behind the neck. The paper towel should be snug, but not pulled so tightly that it tears.
3. Place one of the larger paper towels over the horse's back; again, wrap it snugly, but not too tight. Clip the paper towel closed with a hair clip or a binder clip, by the horse's stomach.
4. Repeat steps 1–3 for the second horse.

Figure 4. This photo shows two toy horses, ready for testing with a fan.

Testing Your Horses

1. Place your horses in front of the fan in a room without drafts.
   1. One horse should be pointed toward the fan.
   2. The other horse should be pointed away from the fan.
   3. There should be some space (about 1 inch) between the horses.
   4. The horses should be a few inches away from the fan, but still close enough that you can feel wind on the parts of their bodies that are farthest away from the fan when the fan is turned on high.
   5. Try to make sure each horse is getting the same amount of wind from the fan.
   6. The paper towels that are closest to the fans on each horse should be the same distance away from the fan.

Figure 5. This photo shows how the test horses should be placed in front of the fan.

2. Turn the fan on high.
3. Feel the paper towels frequently, every 5 minutes.
   1. Use one hand to touch the snout of one horse, and the other hand to touch the snout of the other horse.
   2. In the same way, using two hands at the same time, compare the dampness of the chests.
   3. In the same way, using two hands at the same time, compare the dampness of the backs.
4. As soon as one of the paper towels on the snout, chest, or back of one of the horses feels like it is starting to get dry and crispy, turn off the fan. Leave the horses where they are.
5. Make a data table in your lab notebook, like the one below, and write down which body part on which horse got drier first—the horse pointed toward the fan, or the horse pointed away from the fan. You can write down the word toward for the horse pointed toward the fan, or the word away for the horse pointed away from the fan. You data table will help you keep track of which horse was losing heat the fastest by convection for each body part.

Which Horse Became Drier First? Data Table

6. Turn the fan back on high.
7. Repeat steps 3–6 until a paper towel for each body part starts to become dry and crispy.
8. Remove the paper towels from the horses and repeat Preparing the Paper Towels, Preparing the Horses for Testing, and steps 1–7 of this section two more times, so that you have a total of three trials. By repeating the experiment three times, you'll make sure your results are accurate and repeatable.

Analyzing Your Data Table

1. Look at each body part in your data table and write down which horse became drier first, the most often, in the last column of the data table.
2. For the horse pointed toward the fan, which body part (or parts) became drier first the most often?
3. For the horse pointed away from the fan, which body part (or parts) became drier first the most often?
4. In which direction do you think a horse will point in a cold wind to try to maintain its core temperature?

Variations

• Turn two toy horses away from the fan and cover each of their backs with a damp paper towel. Raise the tail on one of the horses slightly and pin it in place with a ponytail holder. Investigate how raising the tail affects heat loss off the back of the horse.
• Visit a farm on several days under various wind conditions and record:
  1. The direction of the wind.
  2. The speed of the wind, if possible. You can also use an online weather source, like www.weather.com to give you the current speed and direction of the wind for a certain zip code.
  3. The different positions and directions in which the horses are standing.
  4. The position of their tails (raised or lowered).
  5. The position of their heads (up or lowered).
  6. The air temperature.
  How do your behavioral observations compare to your experimental results? Do the horses change their behavior depending on air temperature? Wind speed?
• Try other animal models. Do you get similar results to the horse models?

• For more science project ideas in this area of science, see Mammalian Biology Project Ideas.

Credits

Kristin Strong, Science Buddies

Last edit date: 2009-08-19 09:51:00

Career Focus

If you like this project, you might want to think about career opportunities in Mammalian Biology.

Veterinarians help prevent, diagnose and treat health problems in a wide variety of animals. Regardless of whether the animal is a family pet, a prize-winning race horse, a dairy cow, a circus lion, or seal in a zoo, its healthcare depends on veterinarians. Learn more about this career: Veterinarian.