Dear Scouter Atom,
My Patrol Leader tells me to put on another layer of clothing, instead of piling more wood on our campfire. She says the clothes will keep me warmer and be more climate friendly. How can clothes keep me warmer than a fire?
1st Gumboot Scout Troop
That’s a great question, and something that’s important to consider in all seasons.
First, let’s talk about how our bodies regulate temperature. Heat is transferred between objects in three ways: radiation, convection and conduction.
Heat radiates away from our body, transferring heat from our skin and body to the surrounding environment. Think about climbing into your sleeping bag at the end of the day. The bag is initially cool, but warms up as heat radiates away from your body. Then, the sleeping bag’s insulation retains most of that heat to keep you comfortable all night. Alternatively, our bodies warm up if they stand near a warm fire or a radiator. A radiator gives off heat from hot water through radiation.
Our bodies regulate internal temperature by a process known as convection – the transfer of heat through the movement of liquids and gases. As blood moves through the body, it carries heat from the core out to fingers and toes. Some mammals sweat to keep them cool in warm temperatures. The liquid evaporates off the skin, carrying away heat. Externally, a strong gust of wind can quickly carry heat away from your body and speed up the evaporation process – cooling you down too fast.
Every time two objects with different temperatures come into contact, heat is conducted from one object to the other. Holding a hot water bottle will warm up your hands, but holding a bottle full of ice will warm up the ice. Warm blood from your core conducts heat to cold fingers and toes. Adding insulating layers between your body and cold objects (like the ground, snow or water) helps keep body heat stable.
Now, let’s talk about how layers can help keep you warm on your great Scouting adventures.
Campfires are a great source of heat. But, if you aren’t dressed properly, you won’t be able to hold on to that heat and all of your work will be for nothing. Think about using an insulated thermos instead of a cardboard container to transport a hot lunch. The thermos keeps the food warm, without the need to reheat anything. If you keep hot food in a cardboard container, it won’t stay warm as long and you will need to heat it up again – wasting time and energy.
Smart layers increase the amount of heat your body can hold on to, limiting the amount of fuel and energy you need to put into staying warm. You’ll be able to keep more heat to yourself and stay warmer longer on your own. A good base layer will wick any sweat and moisture away from your body, helping you stay dry and stopping you from overheating. Mid layers act as an insulator, keeping the heat in and the cold air out. You can always put on another mid layer to add some insulation if you’re feeling cold. This will keep in the heat your body is already generating. Finally, a wind and/or waterproof outer layer will keep the elements out. Wind can quickly remove heat from your body and water can quickly soak through your layers leaving you cold and clammy, so this is an important step. Layers will also add insulation between you and any colder objects you come into contact with like the ground or metal pots.
This infographic from Scoutmaster Clarke Green gives a quick summary of the different layers you should have in your pack.
Still not convinced? Create different insulating systems to protect a hot water balloon from the elements of your freezer and test it out for yourself.
What to do:
- Design three different layering systems to keep your hot water balloon warm. Start with one layer for the first balloon. Add another layer or two to the second one, and yet another few layers to the third.
- Measure the temperature of each balloon system.
- Place each layered balloon inside the freezer at the same time.
- For a control, fill a hot water balloon, take its temperature, and place it in the freezer with the other balloons.
- After an hour, check on your balloons. Which one is the coldest? Which one is the warmest?
Holding on to more of your body heat means you can save that extra log for your breakfast fire, or leave it for the next person. Reducing the amount of wood burned in each fire also cuts down on the number of trees that are chopped down for firewood each year.
Until next time!
Scouter Atom is a Colony Scouter with a passion for STEM adventures. There is no question too small, no question too large – if you have a question, Scouter Atom has an answer. Send your questions to firstname.lastname@example.org.