Note: This blog is a serialization of a book titled Field Trips for All of Us: Transformative Adventures for Children and Their Adults. Here is the preface. The first field trip is Taking Education Outside.
Introduction
Many people played around with mixing different substances together as children; making potions, soups, mud pies, and other creations. Many of us, before we’re able to pronounce the word “mixture”. My son Noah called his combinations miskers and, as with the miskers many of us have made, his were bizarre concoctions were made with anything he could get his hands on in the kitchen or bathroom. We’ll use the term mixture here to include any substance made by combining two or more other substances. Using the term in this way helps us look at everything, from the universe itself down to subatomic particles through the lens of mixtures and combinations. This lens focuses our attention on how things (be they recipe ingredients, elements, genes, or ecosystems) combining together helps determine how they work.
Educational Tip
Sense-Making Discussions: As we’ve said elsewhere and will say again, the purpose of sense-making conversations is not to transmit information but is to get kids thinking about a topic. Such discussions must be responsive and unscripted. We present these questions as examples of the kinds of questions you might want to ask during mud play.
For example, I started talking to a group of 4-year olds about this topic when we were making mud. I had already asked them to tell me what they knew about mixtures and their answers led me to believe they had a pretty good idea that mixtures are combinations of other substances. Then we started making mud to use as a building material. As we did I reminded them of the story of Goldilocks and how the first porridge she tasted was too hot, the second too cold, and the third was just right. We then talked about how their mud had been too dry to work with, then we added more water and it was too wet, and asked how we could get it just right. I used the same story with somewhat older kids (7-12 years old) to explain that the right proportions could be described in terms of the Goldilocks Zone. In both cases we focused on developing an intuitive grasp of the importance of proportions in our mud mixture.
As you play in the mud with kids, rest assured that learning happens naturally. We animals are very curious about the things around us and making sense of the world around us is central to our survival. Infants spend a lot of time making sense of their direct sensory-motor experiences. As we develop our sense-making generally builds. Direct sensory-motor experiences are also very important for Toddlers. Toddlers use these experiences to help them build representations of the world, which enable them to name and describe their experiences. Older children continue to make sense of their world starting with their sensory motor experiences and representing those experiences. They add the ability to abstract general patterns and relationships from their representations and use those patterns and relationships to explain new observations and make predictions. It is often useful to have this same sequence in mind as we nurture our children’s learning. Start with direct sensory-motor experiences, move on to naming and describing, and then abstracting general patterns and relationships and using those patterns and relationships to explain new observations and make predictions.
Understanding proportions, intuitively, is an important sub-skill involved in any activity that includes making mixtures. Activities like baking, cooking, mixing natural medicines, and preparing building materials like mud, adobe, and cob all require an intuitive understanding of mixtures.
An intuitive understanding of the role of proportions in mixtures builds on knowing the ingredients in the mixture and the properties of each ingredient (what it brings to the mix). For example, knowing that mud is a mixture of water and dirt and that water brings wetness to the mud, while the dirt brings dryness. This means that if our mud is too wet for our purposes we need to add more dirt and if our mud is too dry we need to add more water. Another aspect of developing an intuitive feel for proportions is recognizing that if we have a mixture that’s just right and we want to make more we need to add more dirt and more water. This is a step toward recognizing that if we have a mixture that’s just right and we want to make more we need to add more dirt and more water in equal proportions.
Activity
Making mud: For many children, mud is a favorite mixture! Making mud to form into shapes like balls and bricks is great fun and a gateway to building with natural materials as our ancestors did and many present-day animals, including humans do. Groups we work with have made mud pies, mud bricks, and other mud sculptures and shapes in a variety of contexts: mud kitchens, making seedballs, playing by a creek or pond, making cob balls and adobe bricks, and when we play with changing how water flows into a landscape from a hose. All of these activities provide an excellent context for talking about mixtures. And, mud makes a perfect first mixture recipe as it has only two ingredients with very different properties that go together to make a mixture that has its own set of properties very different from either of its ingredients.
Thinking about substances as mixtures involves at least three questions:
What is it made of?
What does each component bring to the mix?
What is the proportion (relative amount) of each component in the mix?
When I first have sense-making discussions with kids about mixtures I tend to keep the language as informal as possible. I usually use the words recipe and ingredients when I talk with kids about mixtures. While playing with mud (I almost always join in of course), I might intersperse questions like the following if and when, the time is right.
Is mud a mixture of other stuff?
What ingredients do we mix together to make mud?
What is dirt like when it is dry?
Can we shape it?
What is it like when it’s mixed with water?
Can we shape it?
Can mud be too wet to shape?
What can we do if our mud is too wet to shape?
Is there more water or dirt in the mix?
If we want to make more mud, should we use the same amount of each?
Building with mud: Humans have used mixtures of mud and organic fibers as a building material for thousands of years. Other animals also use this mixture as a building material. Cob and adobe are two names for this mixture. Both adobe and cob include the same ingredients: sand, clay, some form of organic fiber (like straw), and water. A difference between adobe and cob is that adobe is traditionally mixed using native soil that contains sand, clay, and some organic matter (among other things, see Playing in the Dirt for more information about the ingredients in soil) while sand and clay are added as separate ingredients to cob.
This is a great opportunity to present a visual comparison of the relative amounts of sand and clay in our cob. A good rule of thumb for the proportions of sand to clay is two parts of coarse sand to one part of dry clay. Just pour out two cups (or other unit) of sand next to one unit of clay. Then, explain that this is a recipe you read about for cob but you’d like to make more cob. Then, pour out two cups of clay below the one cup pile [needs an illustration] and ask the kids how big of a pile of sand you’ll need to go with this new amount of clay. Remember, your initial goal is not to get them to give any particular answer but to support their engagement in making sense of the question. Once you’ve come up with a couple of possibilities, go ahead and try them out adding straw and water to your various recipes including the original 2:1 sand to mud recipe as described below. You can do the mixing on bare soil or in a container.
Mix dry ingredients together.
Add water until your mixture is sticky and moldable.
Add a little straw and mix it in. Always start with less than you think you’ll need. Think of the straw as tying your cob together. You want to have enough to connect the other ingredients. Each handful of cob should have long strands running through it, but not so much that it makes the mixture hard to work with.
Now you can use your cob to make shapes including bricks and to make fairy houses and/or small models of natural buildings. For larger building projects, most folks mix their ingredients on a tarp. This process includes a lot of cob stomping in bare feet and rolling of the cob blob back and forth by alternately lifting one side and the other. This whole process is great fun! There’s lots of information about building with cob, including making cob ovens, on the internet.
Some Nature Science Stuff
Mixtures and Systems: So far, we’ve been using the word mixture very generally to mean any substance made by combining two or more other substances. Scientists refine this definition by adding that mixtures are physical not chemical combinations. Things that are physically combined can be separated using physical means. For example, water can be removed from soil by heating the mixture; causing the water to evaporate (a physical process). When things are physically combined they also keep their individual properties. The crushed rock in soil still behaves like crushed rock; solid at rock temperature, crystal structure, same density, etc. When is a combination not a mixture? One answer is that combinations of substances that bond chemically are not mixtures. Water is a combination of hydrogen and oxygen. These two substances bond with each other when combined. Water is a special kind of combination known as a compound. Another technical feature of mixtures is that they have no defined structure. Compounds like water do have a structure. In the case of water, there are always two hydrogens bonded to each oxygen and in a particular shape. There are also a lot of physical combinations of things that are not mixtures because there is a pattern to how they are combined. The device you’re using to read this is a combination of many different things but it is not technically a mixture because the arrangement of its parts is important to its function. Such combinations can be thought of as systems. To learn about systems, consider the Build a System field trip.
Powered by diversity: Part of the definition of a mixture is that the properties of each of its ingredients do not change when they are mixed together. However, mixtures, like systems, have properties that emerge from their combining. For example, dry soil is difficult to form into shapes but just add the right amount of water and soil becomes moldable mud. This is the amazing thing about mixtures! Even without any specific pattern or structure, combinations of materials often have useful emergent features. Being powered by diversity is a general feature of combinations at all levels. Protons and neutrons are formed from different kinds of quarks. Electrons and protons stick together because of their differences. Differences in their configuration of electrons in atoms lead them to bond together to form molecules. This pattern of being powered by diversity holds through the combination of diverse little molecules to form macromolecules, diverse macromolecules in cells, diverse cells forming organs, organs forming organisms, diverse organisms forming ecosystems, and beyond to our global ecosystem.
Wrap Up
Mixing things together is fun for kids and an important activity for most adults. Making sense of mixtures includes understanding that their behavior depends on their ingredients, the different properties of each ingredient, and the proportions of each ingredient. Mixtures come up when we’re playing, cooking, preparing building materials and in many other contexts. Technically, mixtures are physical combinations including two or more components that are not bound together by and have no patterned structure. Systems are also combinations of two or more components. They do, however, have a patterned structure. In fact, it’s the pattern of relationships within and between systems that enables them to do what they do. The coolest thing about mixtures is that they are powered by diversity. Each ingredient brings its own super powers and new superpowers emerge from their combination.
Remember to turn the mixture lens on anything.You can ask young folks (and yourself!) these questions in reference to everything from a bowl of cereal, to a tree, to a piece of granite, to your home, to your family! What is it made of? What does each component bring to the mix? What is the proportion (relative amount) of each component in the mix? I’ve asked these questions of the children I work with while they were playing, building, gardening, and even snacking and I’ve been amazed at the depth of their answers!
Have fun out there in our incredible mixed up world!