Water & Light A hands-on workbook for pre-school to middle schoolers, using light as a tool for examining and cleaning our wastewater.
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Water and Light Hi Kids! I’m Kelvin the Pipe Protector!
We put a lot of things in our water (and down our drains). Things like toilet paper, or food scraps, or shampoo, or toothpaste. And even though we never see that stuff again after they go down the drain, we probably KNOW that they do not disappear. But sometimes, we put things in water and they actually do seem to disappear. Like when we add salt to our water before boiling it. What do we think happens to all this stuff? And how do we tell the difference between water that is clean and water that has stuff in it? It turns out, we have lots of different tools to help us tell the difference. Light is one tool we use all the time across our system. We use light to inspect our pipes underground. We also use light to tell how dirty our water is.
In this activity, we will be using light, just like our scientists and engineers, to help us see what happens to all that stuff we put in our water, even if it looks like it disappears.
FIRST, make sure you have all of the items you will need for this activity:
Two clear plastic or glass containers, (lids optional). Recycled food containers work great! You can even use a simple plastic cup.
Salt. You can also use sugar, a sugar substitute, baking soda, or really any powder that will “disappear” when we put it in water. Salt is best though.
Something to stir with. This might be a spoon, or a straw, or a coffee stirrer, or a stick.
A light source. This could be a small flashlight, a cat toy laser, or the flashlight app on a cell phone.
Water.
Pen, colored pencils, crayons, or markers for sketching.
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Getting Set Up NEXT, prepare your materials for the activity:
Prepare your containers. Wash them and remove enough of the label so that you can see clearly into them.
Fill your containers. Fill half way with water.
Gather your salt (or other powder) and your light source.
Gather your containers, stirring tool, and your sketching supplies together. Some towels for cleaning up are nice to have, too.
Powder and Water
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LET’S BEGIN: What happens to our powder when we put it in water?
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Take one of your containers filled halfway with water. Open the lid if there is one.
Take your stirring tool and spin your powder gently in the container (make sure not to spill). Go slowly. That way you can watch what happens while you stir and what happens afterwards.
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Take your powder and put a small amount into the container. Make sure to do this slowly so you can watch closely what happens.
Put your container down in front of you and look closely at what happened.
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Draw or Write What You See WHAT DO YOU THINK HAPPENED?
What do you think happened to your powder? Draw or Write what you think happened. Where did it go? What’s happening inside your water?
Compare & Contrast COMPARE AND CONTRAST:
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Now let’s compare our Salt Water and Regular Water to see how they might be different.
...Take your other container filled with only Regular Water. ...Put your two containers side by side so you
can see them both.
.. Look closely at both of your containers.
What’s different about the Salt Water and the Regular Water? . Write or Draw some of your thoughts here
on the page.
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Tools: Using Light Sometimes it can be hard to tell the difference with just our eyes alone. That’s why scientists use tools to help them. Different tools can help us see things we might not be able to on our own.
Right now, we are going to use LIGHT as a tool to help us see and compare our Salt Water and our Regular Water.
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Take your container of Salt Water. Place your light on one side of your container and turn it on.
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Now, take your container of Regular Water. Place your light on one side of your container and turn it on.
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Look down at your container from above. Make sure to take off the lid first.
Look down at your container from above. Make sure to take off the lid first.
Salt
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Tools: Using Light Draw what you see in each container. What do you notice? What do you wonder?
Regular
What can you see with the light, that you cannot see with your own eyes? What does that make you think?
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What Does This All Mean?
Sometimes we put things in our water and we think that they have disappeared, but really they are still there. We just need special tools to see them.
To do this we need special tools. That way we can tell the difference between water that just looks like regular water and water that is actually clean and safe.
Some things that “disappear” in our water are harmless, like salt. Other things can be dangerous.
When we clean our water, our scientists need to make sure everything that might have “disappeared” has been removed.
Sometimes we use complex tools, like centrifuges or microscopes or special meters.
Sometimes we can use very simple tools, like light. Tools of all kinds can help us see things we might miss with our own eyes.
So What Does This All Mean?
It’s easy to think the stuff we put in our water, and down our drains, disappears. By using tools like scientists do, we can easily tell that stuff might still be in our water, even though it looks like it has “disappeared.” That makes it easier for all of us to remember that everything that goes down the drain, needs to be cleaned and removed, and none of it disappears.
The next 4 pages offer some ideas for other simple tools you can try at home.
More Tools for Discovery WATER LEVEL
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How can I use my eyes to see what happens to the height of water when we put stuff into it? This works best when both containers are on a flat surface.
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Take your two containers and fill them halfway with clean water.
Place a line where the top of the water level is on each container.
Label one container Salt and the other container Regular.
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Watch what happens to the level of water as you add spoonfuls of salt. (Feel free to repeat steps 4 & 5 as many times as you like!)
Then take some salt (or other powder) and add spoonfuls to the container labeled Salt.
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What do you notice happens to the water level of your Salt Water? How does that compare to the water level of your Regular Water? What does that make you think?
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More Tools for Discovery EVAPORATION
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How can I use my eyes to see what happens when I make the water disappear? This test will take a day to complete.
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Mix a powder and water in a jar.
Then take a container lid and gently pour a little into the lid.
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Place the lid on a windowsill or somewhere else warm.
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Look closely at your lid. What do you see?
Come back in a day and see what happens.
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What do you notice happened to your water? What do you notice happened to your powder? What does that make you think?
More Tools for Discovery TASTE
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How can I use my taste buds to test the differences in my water? Only do this if you’re using safe cooking powders like salt or sugar or baking soda.
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Place your containers side by side (you can use three or more containers for this one).
Put one powder in one container, and a different powder in another container, maybe even a third powder in a third container.
Stir them all so you can’t tell the difference by looking at them.
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Pour a little into a separate cup and taste it. See if you can tell if it’s regular water or if it has something in it.
Then mix up your containers so you don’t know which one is which. You might want to label them A, B & C.
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Can you tell the difference between all the different kinds of waters? What does that make you think about your taste buds as a scientific tool?
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More Tools for Discovery COOKING SCALE
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How can I use a scale to tell what happens to the weight of water when we put stuff into it? If you happen to have a scale at home.
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Take your two containers and fill them halfway with clean water.
Label one container Salt and the other container Regular.
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Place each container on the scale one at a time and record the weight.
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Place it back on the scale and record the new weight. (Feel free to repeat steps 4 & 5 as many times as you like!)
Then take some salt (or other powder) and add spoonfuls to the container labeled Salt.
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Watch what happens to the weight of your Salt Water as you add more and more spoonfuls of salt. How does that compare to the weight of your Regular Water? What does that make you think?
What Else Can You Do?
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Scientific Tools Are All Around Us!
There are lots of tools we can use to tell that the stuff we put in our water doesn’t really disappear. Some are tools we might find around the house, like a flashlight or a cooking scale. And some are tools we carry with us all the time, like our eyes, nose, and mouth.
Take a picture using a tool to show us that stuff we put in our water doesn’t actually disappear.
For privacy purposes, make sure your face is NOT in the photo. Then send it to us! You can print out your photo and paste or tape it over our example here, then cut out the whole page on the dotted line, fold it and mail it to us. Or you can email a digital photo to blavender@centralsan.org. We’ll put our favorites online at: centralsan.org/learn.
If you would like to receive a small prize for your efforts, please include your return address in your email.
This is an example of the type of photo you can provide. Make sure there are no full faces showing in the photo.
Paste or tape your printed photo inside the blue box here.
Return Address:
Fold Here
Place Stamp Here
Education Department Central Contra Costa Sanitary District 5019 Imhoff Place Martinez, CA 94553