The Museum Blog

Category: Science

Walking Rainbow Experiment

Walking Rainbow

By Meredith Brustlin, CMNH Educator

We share a lot of different science experiment projects at CMNH. Many of these experiments have instant results - things like vinegar and baking soda bubbling, popcorn dancing, and invisible ink appearing. What I really like about this “walking rainbow” experiment is that it takes some time to see the results (as in, it takes hours to fully see the results!) Although it may not be as exciting in the moment, it is a perfect experiment to practice making predictions and thinking like a scientist. It really gives young scientists time to think and hypothesize and even change their guesses throughout the day. 

To make your own rainbow you will need:

  • 7 clear cups--these can be glass or plastic, just make sure they are perfectly clear (not colorful)
  • Water
  • 6 paper towel pieces (this could be three large sheets cut in half, or 6 of the little half sheets)
  • Primary colors of food coloring or liquid watercolor

Set-up:

  1. Set out the 7 cups in a line
  2. Fill cups 1, 3, 5, & 7 about halfway with water
    1. Leave cups 2, 4, & 6 empty
  3. Fold your six paper towel pieces in half lengthwise and then in half again. Take that long skinny strip and fold it in half so that it can stand up in the cups (pictured above)
  4. Invite young scientists to help you add some food coloring to the cups. 
    1. Ask them--what is the first color of the rainbow? Red! Add about 6 drops of red food coloring to the first cup.
    2. What is the second color? Orange! That cup is empty though, so we will skip that one. 
      1. Add yellow to the 3rd cup
      2. Skip the 4th cup (green)
      3. Add blue to the 5th cup
      4. Skip the 6th cup (purple)
      5. Add red to the 7th cup and ask your scientists why they think you may have done that…!
  5. Next, carefully place your paper towel pieces in between each cup so that they are resting in the colorful water. 

That’s it for set up! Now it’s time to think like a scientist!

Ask your young scientists…

  • What do you think will happen with the cups?
  • Why do you think we left some cups empty?
  • What do you know about primary colors?
    • How do you think what you know about primary colors (that they make secondary colors) will come into play in this experiment?
  • What do you notice is already happening with the paper towel pieces and the water?

Feel free to have your scientists write or draw what they are seeing!

This experiment will take awhile to completely finish and make the rainbow design. It’s a good idea to either do this experiment at night before bedtime, make some predictions, and then wake up and see the walking water rainbow. You could also do this experiment first thing in the morning and then watch it change all day long!

Have fun making a walking rainbow and thinking like scientists! 

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Science Magic: Secret Rainbow

By Colie Haahr, CMNH Educator

This project is fun and easy, and only requires a little bit of prep ahead of time. Kids will enjoy magically making a rainbow appear by adding water to a paper towel. This activity is fun on its own, or it can be set up as an experiment that they can try a few times and record the results.

Materials Needed:

Paper towels
Washable markers
Black permanent marker
Cup for water
Tray or plates 
Pipette, eye dropper, or small spray bottle
Optional: Different brands of markers, highlighter, permanent markers, pencil, pen 

Directions:

  • Prep ahead: This project requires some prep ahead if you want to create a truly “secret” rainbow! You can create more sheets for kids to try as you go if they enjoy the activity! -Use a water based marker to create a rainbow on a paper towel. Remember ROYGBIV! 

-Thin lines work well for this- do not make them too thick because you need to cover them with permanent marker

-Use a black permanent marker to carefully draw over each line, hiding the colorful lines under the dark lines. 

-Optional: create shapes that are different colors, and use the same process to cover them with permanent markers. 

-Optional: Set up the color mixing part of the activity the same way coloring two circles next to one another in primary colors (red and yellow, red and blue, and yellow and blue)

  • Place one of the prepared paper towels onto a plate or tray that is okay to use for an art project (it may get marker ink on it!), with a cup of water and pipette or spray bottle
  • Make a prediction- ask: what do you think will happen when we add water?
  • Ask kids to slowly add some water to the picture
  • The rainbow will “magically” appear when the water based marker dye spreads, and the permanent ink stays in place
  • Try the same method with color mixing, or the colors hidden behind shapes
  • Let the artwork dry completely, and some of the dye will stay on the paper towel once it dries. Too much water can cause the color to wash out completely
  • Alternatives: This also works with a tray of water, and kids can carefully place the paper towel in the water and watch what happens. 

-Make an experiment! To make this a true experiment, try using different types of writing utensils, like markers, pens, pencils, highlighters, etc., and testing each one to see if water changes anything. Compare different brands of markers to see which ones work the best. Make predictions and write down the results! 

Science Information: 

For this activity there were two types of markers used, and they were made of different types of dyes or inks. One was water soluble, and one was not. If the experiment went as planned, the water based markers should have spread color out on the paper towel. These markers have dye that is water soluble, which means that it is able to dissolve in water. 

The permanent marker has a different kind of ink or dye, and it is not water soluble, which means that water will not wash it away. The permanent marker is alcohol based, so it will dissolve in alcohol. If rubbing alcohol were added to the paper towel, it may have changed the permanent marker, but because only water was added, the permanent marker stayed the same.  

The paper towel also played an important part in making this activity work. This activity did not work well on other types of paper, like card stock and copy paper. Paper towels are absorbent, and designed to absorb or suck up liquids. If the paper were waxed paper or something similar, the water would bead up into droplets because water molecules like to stick together. Water molecules still like to stick together on paper towels, but there are tiny air pockets in paper towels, and a soft cellulose material that allows the water molecules to move around the paper towel together. 

References:

https://indianapublicmedia.org/amomentofscience/how-do-paper-towels-absorb-water.php

https://www.thebestideasforkids.com/surprise-rainbow-activities/

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Oil & Water Mixing Sensory Bottles

by Meredith Brustlin, CMNH Educator

There are so many fun experiments that you can try using oil and water. If you’re at the grocery store and thinking about picking up one or two items for your young scientist’s “at home chemistry station” I definitely recommend a big jug of vegetable oil. It’s inexpensive, easy to find, and can be used for tons of science! 

This experiment does some simple MESS FREE oil and water mixing. I especially like this experiment because the experiment itself is quick and can be done over and over again. Some people also use these oil & water mixing bottles as sensory bottles - moving the oil back and forth and watching the gentle waves it makes can be very relaxing. Who doesn’t need a bit of extra relaxation these days? 

Here’s how to make your own:

Materials needed:

  • Small jar or container with a lid that can be securely screwed on (plastic or glass--although with very young scientists you may want to go the plastic route and duct tape that lid on there, too!)
  • Vegetable oil
  • Food coloring

Directions:

  • Fill your container halfway with water
  • Pour vegetable oil in to fill up the rest of the container
    • Watch and see what happens!
  • Add a drop of red or blue food coloring
    • Watch closely again! 
  • Tightly secure the lid of your container
    • Optional: add some duct tape to really seal it in place
  • Watch as the oil and water in your bottles become completely separate and the drop of food coloring makes its way down to the water portion of the bottle - it will take a few seconds. 
  • Gently move the bottle around and watch the oil and water - they stay separate when moved gently
  • SHAKE your bottle! Really shake it and watch as the water and oil temporarily mix
    • What else happens?!
  • Watch closely again as the oil and water slowly separate

The Science: 

There are several different science “happenings” going on during this experiment. 

Oil & Water:

  • Your scientist’s will notice that the oil and water do not mix! The oil sits on top of the water and it always will. This is because water and oil are immiscible. Basically what this means is that water molecules only want to hang out with other water molecules and the same with oil molecules. The oil sits on top because it is less dense or less heavy than the water so it happily floats on top of it. 

Primary/Secondary Colors:

  • Vegetable oil is used for this experiment because it is yellow in color. If we used another kind of oil, like baby oil, you would have to purchase oil based food coloring which isn’t all that easy to find. The yellow vegetable oil automatically gives us one of our primary colors. Blue or red food coloring is added so that when you mix, you get a secondary color! 
    • There are lots of great books you can read/find videos of online to explore primary/secondary colors, check out: 
      • Mouse Paint by Ellen Stoll Walsh
      • Mix It Up by Herve Tullet
      • Monsters Love Colors by Mike Austin

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Science Magic: Glitter & Soap

by Colie Haahr, CMNH Educator

Try out this easy experiment with materials you already have at home! This experiment is about surface tension, and you can make glitter magically “dance” in a bowl of water! The reaction is quick, but kids love trying it more than once. This could be a good experiment to try before transitioning to water play, which always seems to be a hit! 

Materials Needed:

Shallow bowls or plates
Water 
Glitter, Pepper, Cinnamon, or All Spice 
Toothpicks or Q-tips
Dish Soap
Toothpaste
Cooking Oil

Directions:

  • Set up: Pour water into bowls, and place a very small amount of all of the other liquids into lids or small bowls. A pitcher of water is helpful to reset the experiment. The experiment works best with dish soap, but using a few other substances makes it more of a true experiment, where some will work and some will not. 
  • Optional: have a pencil and paper handy to record observations and hypotheses 
  • Pour about a teaspoon of glitter into one bowl of water, and a teaspoon of whatever spices you would like to use into another. You want the glitter and spices to cover the surface of the water
  • Make an observation: what happened when we poured the glitter/spices into the bowl? 
  • The glitter or spices stay on the surface of the water because they are hydrophobic, and they do not dissolve in water like salt or sugar would. 
  • Carefully dip the end of a clean toothpick or Q-tip into the liquid dish soap, and poke it right into the center of the bowl
  • Make an observation: What happened to the glitter/spices? The glitter should move quickly to the edges of the bowl when the soap touches it. 
  • Repeat the process with the toothpaste, cooking oil, hand soap or anything else you decide to try
  • Optional: write down what happens each time you try the experiment 

Science Information: 

Water molecules like to stick together, so when you pour a drop of water onto something non-porous, like waxed paper, the water beads up. Kids usually can picture this happening on a windshield when it’s rainy the rain drops stick together and roll down the windshield. 

When you pour water into a bowl or plate, this creates surface tension. 

During the experiment, you observed that the glitter and spices in the water bowls stayed right on top. Even though water molecules like to stick together, they do not always stick to other things, like the glitter and spices. The surface tension of the water allows these small particles to float on top! They do not dissolve, and usually, they do not get saturated and sink. 

When you added different substances to the water, some caused the glitter and spices to move away to the sides of the bowl. Now experiments can be tricky, and they do not always work perfectly, but the oil should have made no changes to the water bowl, and the soap and toothpaste should have caused the particles to move. The substances that made the glitter and spices had something in common: they all clean things! 

Dish soap should have worked the best, and this is partially because dish soap has molecules (teeny tiny parts) that are BOTH hydrophobic and hydrophilic. Wait, that would mean the soap molecules repel water molecules, and attract or bond to them! This is true, soap is a good cleaner because it can pull things like oil out of water because of the hydrophilic properties, like when we wash dishes, dish soap helps to get rid of grease and oil that water alone can’t remove. 

When the soap touched the water bowl, it broke the surface tension of the water, and that’s why we could see the glitter and spices move. Soaps and cleaners are designed to break down the surface tension of water. This helps make them good cleaning tools. When you added the dish soap or toothpaste to the water it broke up the surface tension. The water molecules, however, want to stick together and maintain that tension, so they move away from the soap, carrying the glitter and spices with them! We can see the reaction because there are particles floating on the top of the water. The water would still move when soap is added, but because it is clear, we can’t see it. The glitter and spices help us see what’s happening in the water bowl! 

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Tie-Dye Butterflies

by Meredith Brustlin, CMNH Educator

I love this art activity. It’s easy to do with items you probably already have at home. It’s such an interesting and fun process-art activity that your young artists will probably want to try it again and again and again!

Materials:

  • White basket coffee filters
  • Washable markers
  • A binder clip 
  • A pencil/straw/craft stick
  • Clothespin
  • Small pieces of colorful paper or pipe cleaners

Directions:

  • Give each young artist a coffee filter and invite them to create a circular design on it using washable markers
  • Once finished, fold the coffee into a triangle
    • Attach a binder clip to the top/wide end of the triangle
    • Slide a pencil through the top of the binder clip
  • Put a tiny bit of water into a glass or jar
  • Place the triangle in the jar
    • The pencil will help to hold the triangle in place across the top of the cup or jar so that it does not fall in
    • There should be JUST enough water that the tip of the triangle is barely touching
  • Watch closely as the water climbs up the coffee filter triangle!
    • What happens to the designs?! 
  • When the water has climbed all the way up, carefully remove the pencil and binder clip and unfold your triangle
  • Place it on a drying rack and let it to dry fully
    • This should take about 20 minutes

Assemble your butterflies!

  • Scrunch the coffee filter up to make wings
  • Clip a clothespin in the middle to make the bod
  • Add small pieces of colorful paper to the top to make some antennae 
  • Draw a happy face on your butterfly! 

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Science MAGIC: Invisible Ink!

By Meredith Brustlin, CMNH Educator

I was THRILLED to find this invisible ink recipe. Many invisible ink recipes involve holding dried lemon juice messages over a candle and almost setting pieces of paper on fire. Luckily, this recipe doesn’t require any heat and is totally safe---besides the slightly strong scent of rubbing alcohol. However, with it warming up outside--this would be a great outside project!

Here’s how to make your own heat-free invisible ink:

Materials needed:

  • 2 medium-size glass containers (I used Pyrex liquid measuring cups)
  • Q-tips
  • Paintbrushes
  • Paper (white paper works best, you could also use cardstock!)
  • Table covering
  • Cookie sheet/craft tray
  • 1 tsp powdered tumeric
  • ½ cup rubbing alcohol
  • 1 Tbsp baking soda
  • ½ water

Directions (prep):

  • Set up your experiment area, whether inside or outside, by protecting the area with some kind of covering. This could be a plastic tablecloth, trashbag, or some other non-absorbent material. 
  • Place a cookie tray in the experiment area
  • Gather all other materials and have them on hand. 

Directions (activity):

  • Tell little ones that today you will be experimenting with invisible ink! 
  • Invite them to help you mix 1 Tbsp of baking soda into ½ water in one of your glass containers
    • Mix until it is mostly dissolved and keep mixing throughout your experimenting--it doesn’t dissolve all that quickly. 
  • Have little ones draw on their paper with the baking soda solution using q-tips
    • It will be hard to see what they are drawing! They can try writing words or just doing abstract doodles. Anything will be fun to find using the invisible ink decoder!
  • Put aside the drawings to dry
  • While they are drying, make your “decoding” solution
  • Mix 1 tsp turmeric powder into ½ cup of rubbing alcohol 
    • The turmeric solution will stain hands and surfaces--so be careful while mixing and using this solution. At least it won’t set your house on fire, right?! 
  • Once your papers are completely dry, place them on the cookie sheet and paint over them using the tumeric decoding solution. What happens?!?!
  • Watch your paper change color more as they completely dry. 

The Science: 

(For younger scientists):

  • Explain that the baking soda “ink” is changing color because it reacts or changes when it meets the turmeric solution. There is an ingredient in the turmeric that changes the baking soda to that very deep purple color when they meet! 

(For older scientists):

  • Turmeric is a ph indicator. This means that it will change the color of different substances when it interacts with them to show us what their ph is. 
    • Ph tells us the acidity or basicity of items. 
    • Basically, substances go through a chemical reaction when they “meet” a ph indicator and that causes them to change color. 
    • Think about a traditional baking soda and vinegar experiment - they combine and erupt! That is because baking soda is a base and vinegar is an acid. If we tested the ph of vinegar it would be a very different color than the ph of baking soda. 
  • When you paint over the baking soda papers with turmeric, we are seeing that deep purple appear because that is the color that baking soda changes when it interacts with a ph indicator. 

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Make Seed Flyers

by Meredith Brustlin, CMNH Educator

This week, all of our online programming will focus on the earth and being environmentally friendly! 

Try making seed flyers this week. These are fun to make and fun to throw or plant! Plus, the wildflower seeds that you use to create them will be helpful to your neighborhood pollinators. 

Materials Needed:

  • Newspaper or construction paper (torn into small pieces)
  • Water
  • A blender or food processor
  • Wildflower seeds
  • Mini muffin tin (optional)

Directions:

  • Start by tearing up your paper into small pieces
  • Put the pieces in a bowl or a couple different bowls
  • Pour water over your paper pieces and allow them to soak
    • This will take about 20 minutes with construction paper and less time with newspaper
  • Once your paper is soaked, add it to your food processor or blender
    • Process or blend until the paper is fully broken down
  • Now it’s time to make your seed bombs!
    • Smush the paper into your muffin tin or use your hands to smush the paper into spheres
    • If using the muffin tin, put a layer of paper and then sprinkle some seeds on top, then add another layer of paper on top of that and smush it all down
    • If using your hands, put some paper and seeds into your hands and then roll into balls
  • Let your seed flyers dry
    • Let them dry for a few hours in the muffin tin (if you used one)
    • Once they’re a bit dry, transfer them to a drying rack and let them fully dry overnight

Now what do you do?!

  • When seed planting season starts...plant your seed flyers! Or, as the name implies, THROW THEM and see them fly through the air! They will land and start to work their way into the soil. 

Thank you to our Earth Day week sponsor, D. F. Richard! 

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Foil Boats Science Challenge

Foil Boat

by Meredith Brustlin, CMNH Educator

Materials needed:

  • One piece of aluminum foil per young scientist/participant (roughly the size of a standard piece of paper) Make sure all participants have the same size piece of foil. 
  • Sink/tub/plastic bin with about 6 inches of water in it
  • Weights to put in your boat (pennis work great for this!)
  • Optional: other building materials
    • Cardboard, tape, straws, popsicle sticks, etc

Directions (prep):

  • Fill up your water station (sink/tub/plastic bin)
  • Prep materials for each scientist participant--make sure they all have the same materials to use for their project
  • Collect boat weights (ex. pennies)

Directions (activity):

  • Explain to your young scientist(s) that today you will be making boats! 
  • Challenge them to make a boat that they think will hold the most weight and not sink using the materials provided
  • Test your boats by putting them in the water and gradually adding weight!
  • Feel free to re-design and test again. 

The Science:

  • We are seeing two forces at work in this science experiment: gravity and buoyancy!
  • Gravity: gravity is trying to pull your boat and pennies downward towards the center of the earth
  • Buoyancy: buoyancy is pushing the boat towards the surface of the water! 
  • Your boat will float if the force of buoyancy is greater than the force of gravity. 

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