The Waters
We give thanks to all the waters of the world for quenching our thirst and providing us with strength. Water is life. We know its power in many forms- waterfalls and rain, mists and streams, rivers and oceans. With one mind, we send greetings and thanks to the spirit of Water.
Now our minds are one.
From the Haudenosaunee Thanksgiving Address, National Museum of the American Indian
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
Water is life. Land-based people have long recognized its direct importance to humans as one of our most basic needs, along with our need for air, food, community, and shelter. Humans can make it about three minutes without oxygen, three days without water, and three weeks without food. Land-based peoples also know water as a giver of life for all living beings. Modern science tells us that almost all of the biochemical reactions of life require water. Water is often called the universal solvent because it dissolves so many things. The hydrosphere, including the waterfalls, rain, mists, streams, rivers, and oceans mentioned in the Haudenosaunee Thanksgiving Address, is one of Earth's subsystems. It, along with the remaining three - the lithosphere (solid surface), the atmosphere (air), and the biosphere (life), comprise Gaia, the Earth as a system. Given how critical water is to life, knowing how to purify drinking water is an essential skill. In this post, we describe some activities to help you become more familiar with water as the compound most likely to mix it up with others. Our next post about water will focus on separating water from some of its friends so we can drink it.
Activities
All of the activities in this post require water. Some also require other materials that we note at the beginning of those activities. Some children may need help with some of them, like squeezing water from a dropper. We recommend you play around with each activity before offering them to your kids. The first activity introduces the big ideas of this post. If it’s the only activity you get to in this post, that will still be a great start in exploring and coming to understand the features of water that make it essential to all life on Earth.
Making a Mud Milkshake
Materials: One clear quart or liter container with a lid, water, and soil, or enough of each for all of the children in your group.
Put about a cup (¼ liter) of soil into a clear quart or liter container that has a lid.
Fill the rest of the container with water to about an inch (2.5 cm) from the top
Put the lid on your container and pass it around for the kids to shake vigorously.
Set the jar(s) down where everyone can see it (them).
As the components of the soil settle to the bottom of the jar, ask questions like the following to prompt your kids to make sense of what they’re seeing.
What do you see?
Can you see the mud in the water?
What’s happening to the dirt in the water?
Why do you think you’re seeing what you’re seeing?
Why do you think the water is cloudy?
Is the muddy water a mixture? Why or why not?
Would you drink the water as it is? Why or why not?
Is the muddy water a solution? Why or why not?
How would you separate the water from the dirt so you could drink it?
For now, don’t worry about guiding them to answers you're hoping for, just help them reflect on their experiences and try to make sense of what they observe. After asking the last question and listening to their answers, perhaps continue with:
Give your kids an opportunity to try out their ideas about filtering the dirt from the water.
Explain to your students that getting the water clear does not necessarily make it safe to drink.
If the kids really want to drink their filtered water and you have time, you trust that the water and soil you used contain no chemical contaminants, and you have access to fire and a pot, you can boil the water for 3 minutes, let it cool, then drink it. If not, don’t worry, we’ll be devoting a full future blog to this process.
Dissolving Salt in Water
Materials: One clear quart or liter container with a lid, water, and a teaspoon (4 grams) of salt or enough of each for all of the children in your group.
Fill the container with water to about an inch (2.5 cm) from the top
Add a teaspoon (4 grams) of salt
Put the lid on your container and pass it around for the kids to shake vigorously.
Set the jar(s) down where everyone can see it (them).
Ask questions like the following to prompt your kids to make sense of what they’re seeing.
What do you see?
Can you see the salt in the water?
Would you drink the water as it is? Why or why not?
Do you think the salt is still there?
How might you separate the water from the salt so you could drink it?
Is the salty water a mixture? Why or why not?
Is the salty water a solution? Why or why not?
Again, don’t worry at first about guiding them to the answers you're hoping for, just help them reflect on their experiences and make sense of what they observe. After the kids I’ve been working with have been actively engaged in making sense of their experiences with muddy and salty water for a while, I’ll tell them the following interactive science story, opportunistically bringing in their answers.
Both muddy and salty water are mixtures of multiple things. Remember your answers when I asked if you could still see the dirt as separate from the water when they were mixed together; If you could still see the salt separate from the water after we mixed it in? Also, remember, did the dirt settle out? How about the salt? Saltwater is a mixture that is also a solution. Muddy water is a mixture that is not a solution. Solutions are mixtures where you can’t see the mixed-up things as separate.
Dissolving Baking Powder in Water
Materials: One clear quart or liter container with a lid, water, and a teaspoon (4 grams) of baking powder or enough of each for all of the children in your group.
Fill the container with water to about an inch (2.5 cm) from the top.
Add a teaspoon (4 grams) of baking powder to the water.
Put the lid on your container and pass it around for the kids to shake vigorously.
Set the jar(s) down where everyone can see it (them).
Ask questions like the following to prompt your kids to make sense of what they’re seeing.
What do you see?
What do you think is happening to the baking powder and water?
Here’s the science story that explains the bubbles.
Baking powder contains an acid and a base. The bubbles that you see are the product of a chemical reaction between the acid, potassium bitartrate, and the base, sodium bicarbonate, in baking powder. The product of this reaction is salt and carbon dioxide. The bubbles are carbon dioxide gas.
This is the end of the section of this post focused on mixing things with water. We’ve made three main observations.
Water mixes very easily with lots of other things.
It’s not always easy to separate water from the things mixed in with it.
At least one chemical reaction requires water to enable it to happen.
The science story I tell about these observations goes like this.
Some people like to spend most of their time alone. Some people like to hang out with a small group of friends. Some people love to spend time with all kinds of people and enjoy introducing different people to each other. Water is that kind of chemical. Water mixes well with lots of other kinds of stuff and helps other chemicals interact with each other.
Water On a Coin
So far we’ve seen how water interacts with some other chemicals. In this section we’ll explore how water acts on its own.
Materials: One clean coin and an eye dropper bottle with eye dropper or pipette dropper and fresh water for each child (or brainstorm alternative ways to slowly drip water onto a coin).
Ask kids to:
Place their coins on a flat surface above ground level.
Drip water onto their coins one drop at a time, stopping after every couple of drops to look at their coin from eye level. If you don’t have any droppers, kids may be able to shake water off a finger dipped in water onto the coin or brainstorm other ways to drip water onto a coin one drop at a time.
If they are able to slowly add water without jostling the coin, the water will ultimately form an almost spherical dome.
Water On Wax Paper
Materials: One square piece of wax paper about 5 x 5 inch or 15 x 15 cm and an eye dropper bottle with an eye dropper and fresh water for each child
Using a similar setup to the previous step, ask the kids to:
Drip water onto the shiny side of their wax paper one drop at a time.
The drops should “bead up” and form little spherical balls of water. If the kids end up with multiple little balls of water, you can challenge them to get them together to form one bigger ball. Water also balls up on leaves after a rain. Fruits and vegetable skins naturally repel water, beading off and away to prevent rotting. I think my favorite way to drink water is to lick it from leaves right after a rain!
Float a Paperclip On Water
Materials: One cup half full (or half empty, if you prefer) of clean water and two clean metal paper clips per child
Hand out the half-full cups of water and ask the kids to:
Get a paperclip to float on the surface of the water.
While metal is denser than water and will sink in water, it is possible to rest a paper clip on the surface of the water. One way to do this is to bend the second paper clip into an “L” shape and use it to lower the other clip gently onto the surface of the water. This is not easy. You may have to model this for the group and give them time to try, but not enough time to get too frustrated. Model how you deal with the frustration of repeated failures! If anyone succeeds, ask the kids to look very closely at the edges of the paperclip. They may be able to notice that the water bends down slightly around the paper clip.
Exploding Pepper flakes on Water
Materials: One cup half full of clean water and a pinch of black pepper for each child and one eye dropper bottle full of dish soap.
You can do this as a demonstration or, if you have enough materials, give everyone an interactive experience. Using the cups from the above step,
Sprinkle a pinch of pepper flakes on the top of one or more cups.
Prepare the kids to watch carefully as things will happen fast.
Have the kids (or yourself) squeeze one drop of soap in the middle of each cup.
Ask the kids to describe what happened.
Ask the kids, do you have any ideas about why some of the pepper flakes sank and some slammed into the side of the cup?
Now repeat some or all of the preceding water experiences checking out the impact of soda on water piled on a coin, the water balls on wax paper, and the floating paperclip.
Picking up Dirt with a Wet Finger
Materials: Some water and some soil
Water helps some things stick together.
Ask the kids:
To stick their fingers into dry soil.
To wet their finger and again stick it into dry soil.
To wet their fingers with soapy water.
What happens in each case?
Making Sense of the Water Experiences
So, we now know that water piles up on pennies, forms balls on wax paper, and can support the weight of a paperclip with some bending around the edges. We have seen that adding soap to water results in pepper on the surface rapidly moving towards the edges of a cup and water not piling or balling up. We have also experienced that water can make dirt stick to our fingers and that dirt doesn’t stick as well when we use soapy water.
Ask your kids to describe what they observed. Keep prompting them until they’re done and then add any of the above observations that they don’t recall.
Once the kids have summarized their observations, ask them thought-provoking questions like the following. Pay attention to their answers, but don’t worry about whether their answers match yours.
Why might water pile up and ball up?
What did you observe with the paperclip and what do you think explains what you observed?
What happened to the pepper flakes? Why?
What happened when we dropped soap on to the piles and balls? Why might that have happened?
What happened with dirt and our fingers when our fingers were dry and wet? Why?
Demonstrate How Magnets are Attracted to Each Other
Materials: Two or more magnets
If you have enough magnets to give every child two of them, do that. Else, demonstrate how magnets stick together.
Orient the magnets so that they stick together and hold the upper one to demonstrate that the lower one sticks to it, or ask the kids to try that with their magnets if you have enough to distribute them.
Put a paperclip on each side of the magnet and show how they both stick to the magnet.
For now, again focus on asking your kids thought provoking questions while noting but not worrying about their answers.
Could the way magnets stick together have anything to do with water piling up on a coin or balling up on wax paper?
Could the way magnets stick together have anything to do with the way we got the paperclip to sit on top of the water?
Could little pieces [molecules] of water on the surface of a cup stick together like magnets?
After your kids seem to have said all they have to say about their observations of and thoughts about water’s behavior, you can share this science story with them.
The tiniest pieces of water are called water molecules. Water molecules are a little bit like mini magnets. Each one has a positive and a negative side or pole. The positive pole of one water molecule sticks to the negative pole of another, a lot like two magnets. Not all molecules have poles. The science word for molecules with charged poles is polar molecules. Because of the way water molecules at the surface of the water pull at each other, they form a skin on the water’s surface.
Science
Here is some additional science for you and maybe to share with kids who seem especially interested in water.
Things combining to make new things is fundamental to how our universe functions. Quarks combine to form protons and neutrons. Protons, neutrons, and electrons combine to form atoms. Atoms combine to form molecules. Molecules combine to form large biological macromolecules. Biomolecules combine to form prokaryotic organisms, which combine to form eukaryotic cells, which combine to form multicellular organisms, and so on.
Things combine in one of two ways. Sometimes things combine in a patterned way. For example, water molecules are a patterned combination of one oxygen atom and two hydrogen atoms. You are a patterned combination of organs. Your cellphone is a combination of different components. Combinations like these that have specific relationships between their parts are called systems (see, The Build a System Game for more information and activities related to systems).
Sometimes things combine in an unpatterned way. We call those kinds of things, mixtures. My compost bucket contains a mixture of many different things. Muddy water is also a mixture, as is salt water. Some mixtures, while unpatterned do have an observable structure, but that structure does not follow any pattern. The contents of my compost bucket and muddy water have unpatterned visible structures. Things like this are heterogeneous (i.e., of different kinds) mixtures. Mixtures that have no visible structure are called homogeneous mixtures. Most homogenous mixtures are solutions. Saltwater, our atmosphere, and steel are liquid, gaseous, and solid solutions. The main ingredient in a solution is called the solvent, and the things dissolved in the solvent are called solutes. In saltwater, water is the solvent, and salt is the solute. Folks often refer to water as the universal solvent because so many things dissolve in it.
As we mentioned in the introduction to this post, almost all of the chemical processes that happen in living things occur with the help of water. So, it should be no surprise that we are between 55%-60% water. In the activity section of this post, we discussed that water has these essential roles because it can mix it up with many different substances. It is a great mixer because it is a complex, dynamic, structured liquid (at most surface temperatures on Earth), a polar molecule capable of forming hydrogen bonds, and can act as both an acid and a base. Being a complex, dynamic, structured liquid means water dances with many dance partners. Any cup of water contains many water (H₂O) molecules, some H+ cations, and some OH- anions. These forms are in dynamic equilibrium. This means that water molecules are constantly splitting and reforming. Water molecules are polar because oxygen tugs on its electrons more strongly than hydrogen. Chemists call this strength of pulling an atom's electronegativity. Oxygen’s higher electronegativity results in a higher electron density near its nucleus than hydrogen. This leaves the oxygen with a negative charge and the hydrogens with a positive charge. This enables water molecules to form weak intermolecular hydrogen bonds with other molecules, including other water molecules. The hydrogen bonds between water molecules are responsible for water’s surface tension. The differential charge between oxygen and hydrogen atoms in a water molecule is also partially responsible for water's ability to facilitate chemical interactions between other molecules.
Education
As a professor of Education, I was tasked with teaching teachers about scope and sequence. Scope is what is included in a curriculum. Sequence is the order of presentation. As a forest educator, I now talk about bumping into ideas as we wander the “curriculum” as analogous to coming upon different locations in the forest from various approaches as we wander the forest. This does not mean I don’t think about sequence in some contexts. The sequence of activities in this post is very deliberate. The early tasks present less demanding sensory-motor challenges. The concepts also become increasingly complex in later tasks. For this particular post, I thought first about what I wanted children to make sense of about water. Then, about the activities and conversations that might support those understandings. Finally, I thought about how those understandings build on each other and planned a sequence of activities. My thinking was not really that sequential. There was a lot of moving back and forth between thinking about a sequence of ideas, activities, and the link between the ideas and the activities. One of the many advantages of using interactive sensory-motor activities like mixing soil and water or salt and water is that people of all ages with different prior knowledge can all experience something that will likely inspire their curiosity and motivate them to make sense of what they experienced. Diverse people will not all make the same sense but can all engage in sense-making about the same experience.
Wrap Up
Water is essential to life on Earth. It loves to mix it up with other substances. Water’s molecular structure enables it to stick to itself and facilitate vital chemical reactions in us and all life on Earth. One of the advantages of offering kids rich sensory-motor activities is that those kinds of activities can be used with folks with very different prior knowledge to prompt their sense-making. In our next water post, we’ll talk about using filtering, pasteurizing, boiling, and distilling to make mixtures of water and other substances safe to drink.