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20 minute labs blood logo | Yellow Scope



halloween kids  | Yellow ScopeHalloween is just around the corner! Maybe you need some  fake blood for your vampire costume? Or maybe you just want to have fun doing some spooky science in your kitchen this weekend.  

In this month's 20 Minute Lab, we'll make costume blood using everyday items from your baking shelf! 

Did you know in old black and white movies that they used to use chocolate syrup for blood? But that won't do in our real world of color!

halloween icons | Yellow ScopeAlso, to make fake blood look real, the liquid needs to be thicker than just red-colored water.

In this experiment, we'll create thick, dark, realistic-looking blood. You'll have all the other trick-or-treaters in awe!

NOTE: If making fake blood is a bit too spooky for your little scientist, check out our Bubbling Brews Experiment!

WHAT YOU’LL NEEDfake blood supplies | Yellow Scope blog

  • 4 ounces water
  • 2 cups powdered sugar
  • 2 tablespoons cocoa powder
  • 0.1 ounces red food coloring (about a third of a typical bottle)
  • blender
  • tablespoon
  • measuring cup
  • clean up towel
  • optional: wooden spoon or spatula (for scraping down the sides of the blender)

NOTE: though this recipe is safe, edible, and can be cleaned up with soapy water, it may stain, so choose clothes that can get messy!


  1. blender | Yellow Scope blogPlace the water in the blender.
  2. Add the powdered sugar, then blend until thoroughly mixed. You may have to stop once or twice to scrape down any sugar that's stuck to the sides.
  3. Add the red food coloring and blend well.
  4. Add the cocoa powder and blend well. Again, scrape down the extra cocoa stuck to the sides.
  5. That's it! You've made a batch of blood!
  6. How you apply your blood will depend on what you need it for, but drizzling it from a spoon works great if you just want it to fall naturally on your skin like this:

fake blood on hand | Yellow Scope blog


What's going on?

water vs molasses | Yellow ScopeWhat makes this fluid different than just using colored water?

All liquids flow, but some flow faster than others. Viscosity is the property of a liquid that describes how fast or slow it will flow. Usually, the thicker the liquid, the more viscous it is and the slower it flows.

Water is NOT very viscous - it flows very well. Think about pouring water out of a bottle - it comes out pretty fast, doesn't it?

Molasses, on the other hand, is much more viscous than water. Molasses flows very slowly - you might even have to use a spoon to get it out of the jar. 

Blood has a viscosity in between water and molasses; it's not as viscous as molasses, but it's about four times more viscous than water. In addition to water, blood is made up of cells and proteins, which make it thicker and more viscous.

For our fake blood recipe, we started with water. To make it thicker, we added powdered sugar and cocoa to imitate the viscosity of real blood. Did you notice that the mixture got thicker when you added the sugar? The cocoa powder also helped to thicken the mixture. In addition, the cocoa powder added a brownish color to make it look more like real blood - which is quite a bit darker than just bright red food coloring!


Let us know what you did. Share your photos and results with us on Facebook, Twitter, Instagram, or send us an email to We love getting your messages!

For more exciting experiments, check out our Yellow Scope Science Kits on the Shop tab of our website!



rainbow | Yellow Scope blogIsn't it exciting to see a rainbow? The beautiful array of colors is a wonder - it may seem like magic, but we can understand rainbows through science!

Put simply, rainbows occur when white light from the sun bounces off raindrops at a particular angle and splits into all the colors we can see.

In this month's 20 Minute Lab, we'll make our own rainbows using common liquids from your kitchen! Instead of splitting light, we'll make our rainbows using density.

Like real rainbows, this one won't last forever, but it's sure neat while it does.


  • rainbow jar supplies | Yellow Scope blogsmall clear glass jar (we used a small mason jar)
  • honey (generic brands work fine)
  • light corn syrup
  • blue or green dish soap
  • canola or olive oil
  • different colors of food coloring
  • rubbing (isopropyl) alcohol (91% works best, but 70% will do - it's what we used)
  • a small bowl (or multiple bowls if you don't want to clean the same one out a few times during the experiment)
  • spoon
  • eye dropper
  • water

NOTE: the amount of each liquid you use will depend on your jar's size and how thick you want to make the rainbow stripes. For each liquid, you will want to use equal amounts, except for the oil - you will use double the amount. In the Yellow Scope lab, we used half a cup of each liquid and a full cup of oil. 


  1. rainbow jar pouring | Yellow Scope blogMaking sure not to touch the sides, pour the honey into the center of the jar. (If your honey is crystallized, you can scoop some into a small bowl and heat for 20 seconds in the microwave).
  2. Pour the corn syrup into a small bowl. Add 2 drops of red and 1-2 drops of blue food coloring. Stir to make the syrup purple.
  3. Gently pour the syrup into the jar on top of the honey. (Make sure to pour in the center of the jar, avoiding the sides.)
  4. Now add the dish soap, again avoiding touching the sides of the jar.
  5. Measure the water into a small bowl and add food coloring. If your dish soap was blue, make the water green by adding 2 drops each of yellow and blue coloring. If your dish soap was green, add 2 drops of blue coloring to make the water blue. Stir to mix.
  6. Again, gently add the colored water to the center of the jar.
  7. Now add twice the amount of oil to the jar. The bottom half of this layer will be the 'yellow' layer, and the top half will become the orange layer.
  8. Measure the rubbing alcohol into a small bowl and 3 drops of red food coloring. Stir to mix.
  9. Using the eye dropper, carefully add the rubbing alcohol to the jar. This time you want to squirt the alcohol down the side of the jar. This prevents the alcohol from mixing with the water layer.
  10. Being careful to keep the liquid still, hold your jar to the light and admire all the colors!

rainbow jar | Yellow Scope blog


What's going on?

lava lamp pour | Yellow Scope blogWhy don't all the different liquids just mix together instead of forming layers? Well, each liquid has a different density. The different liquids stack on top of each other, with the most dense on the bottom and the least dense on the top. 

Density refers to how much stuff can be packed in a given space. Scientists call the “stuff”, mass and the “space”, volume.

You might remember from last month's 20 Minute Lab, Lava Lamp in a Glass, that some molecules are larger than others. Some liquids are made up of small molecules that are packed tightly together (more dense), while other liquids are made of large molecules that are more spread out (less dense).

Liquids made up of smaller molecules, like water, are more dense and sink toward the bottom. Liquids made up of larger molecules like oil are less dense and don't sink as much. 

oil water molecules | Yellow Scope blog





    In this experiment, you poured the liquids into the jar in a specific order, from the most dense (honey) to least dense (rubbing alcohol). In this way, each new layer stacked on top of the layer below it. You could repeat the experiment and try adding the liquids in a different order to see what would happen!

    NOTE: If you used 70% rubbing alcohol (like we did), that means that the other 30% is water. This means that when you added the alcohol, some of it sunk into the oil (creating that orange layer), since water is denser than oil and wants to go underneath the oil layer!





    Let us know what you did. Share your photos and results with us on Facebook, Twitter, Instagram, or send us an email to We love getting your messages!

    For more exciting experiments, check out our Yellow Scope Science Kits on the Shop tab of our website!

    20 minute labs lava logo | Yellow Scope blog



    lava lamps | Yellow Scope blogHave you ever seen a lava lamp? They're basically an ongoing chemical reaction in a bottle! They were a big hit in the past, and people would buy them to add some fun light and a mesmerizing visual to their room. 

    In this month's 20 Minute Lab, we'll use some household items to make our own lava lamps!

    This experiment is great because it's fun day or night (with a little flashlight help), and you can use the 'lamp' over and over again!

    Note: make sure NOT to drink or taste your lava lamp - it's would taste gross and wouldn't be good for your body!


    • lava lamp supplies | Yellow Scope blogSeveral tablets of Alka-Seltzer (generic brands are fine)
    • vegetable oil (about 2+ cups)
    • food coloring
    • drinking glass
    • measuring cup
    • water


    • tray (to catch spills)
    • flashlight | Yellow Scope bloglarge flashlight (for nighttime fun!)
    • chopstick (for experimenting with stirring)
    • extras of everything to make more than one lava lamp!


    1. lava lamp steps | Yellow Scop blogFirst, fill your measuring cup with 1/2 cup of water.
    2. Add about 20 drops of food coloring and stir. (Remember, you can mix colors by adding 10 drops of different colors or some other combination!)
    3. Fill your glass a bit over halfway up with oil.
    4. Add the colored water to your glass (watch it sink and separate!)
    5. Break one Alka-Seltzer tablet into three or four pieces.
    6. Drop one of the pieces into your glass and watch what happens!


    1. flashlight | Yellow Scope blogAt night (or in a dark room), place the glass on top of a wide flashlight that will stand on its own. (Or you can make your own creative setup - we cut a small hole out of cardboard, then placed the glass on top and a bike light underneath).
    2. Turn the lights off, then add your Alka-Seltzer tablet and watch the lit up effect!

     (Notice how you can just keep adding pieces of tablet to keep the lamp going!)


    What's going on?

    lava lamp pour | Yellow Scope blogBefore you put your tablet in the mix, you poured the colored water into the oil. Did you notice how the water went straight to the bottom?


    That happened because water molecules are smaller than oil molecules, so they can pack more tightly together. This means that water is denser than oil.

    It's sort of like the difference between sand and marbles - sand (like water) is made up of tiny bits, and marbles (like oil) are made of big bits. And you know that you can pack more sand into an area than marbles!

    oil water molecules | Yellow Scope blogWater and Oil Don't Mix

    Water doesn't mix with oil because oil is made of 'hydrophobic', or water-fearing, molecules that want to keep away from water. The food coloring, on the other hand, mixes well with water and dissolves into it (notice how the oil stays the same color).

    fizz | Yellow Scope BlogChemical Reaction

    Alka-Seltzer has sodium bicarbonate and citric acid in it. When you put the tablet in water, a chemical reaction occurs: the sodium bicarbonate and citric acid molecules bump into each other, swap parts, and form new molecules. One of those new molecules is carbon dioxide. 

    The fizzing action is actually bubbles of carbon dioxide gas. The bubbles  rise to the top of the glass, and as they do, they attach to globules of colored water and bring them up to the top as well!

    Once they reach the top, the bubbles burst, leaving nothing to keep the dense blobs of water from sinking again.

    Keep experimenting!

    Try these variations to keep the fun going:
    • alka-seltzer tablet | Yellow Scope blogTry different sizes of the tablet - what happens with a whole tablet? What about with lots of small pieces at once?
    • What happens if you use more water in the glass than oil?






      Let us know what you did. Share your photos and results with us on Facebook, Twitter, Instagram, or send us an email to We love getting your messages!

      For more exciting experiments, check out our Yellow Scope Science Kits on the Shop tab of our website!


      20 minute lab | No Leak bag | Yellow Scope



      Now here's a great trick and a fun way to keep cool in the summer!

      In this month's 20 Minute Lab, we'll use some household items to see how some forms of plastic are leak-resistant, even when you poke holes in it!

      The supplies for this experiment are very simple, and it's a great one for a sunny day. It'll go fast, but you can extend the fun by experimenting with different materials to see what happens.


      • No Leak bag supplies | Yellow Scope bloga few round pencils (colored pencils are often round and work just fine! We happened to have double sided pencils, but that's not necessary)
      • pencil sharpener
      • plastic bag (a zip-lock style is easiest to handle)
      • water



        1. First, you'll want to stand over a sink or be outside in case there are any spills.
        2. sharpened pencils | Yellow Scope blogSharpen all the pencils so they have a good point on them.
        3. Fill the bag about half-way with water and seal it closed. Make sure there aren't any leaks to start!
        4. Now, if you're in a group, you might pause here. Add some fun anticipation by asking your friends what they think will happen when you pierce the bag. Make a hypothesis!
        5. Pierce the bag all the way through both sides with a pencil, leaving some of the pencil poking out on both sides. (Leave the pencil in the bag!)
        6. Observe what happens!
      poke the bag | Yellow Scope blog



      What's going on?

      ldpe |Yellow Scope blogPlastic bags are made out of something called a polymer. A polymer is a type of molecular structure that is a chain of repeated units - like beads on a necklace. ('Poly' means 'many', so polymer means 'many' units.)

      Most bags are made of a particular polymer called low-density polyethylene (LDPE), which has a lot of branching atoms on its chains of polymers. This makes it very flexible.

      LDPE is a very common material because it is light, tough, leak resistant and inexpensive. Perfect for packing material and bags!

      no lead bag | Yellow Scope blogWhen the pencil was poked through the bag, the long flexible molecules formed a seal around the pencil, so the water didn't leak out!

      But if you try removing the pencils, the hole remains because the polymers were permanently squeezed aside by the pencil and can't return to the original shape. So when you're done, you can pull out the pencils to make a summer shower!

      leaking bag | Yellow Scope blog

      Keep experimenting!

      Try these variations to keep the fun going:

      • a different type of bag (produce, grocery carryout bags, sandwich bag, etc)
      • try different types of pencils - bigger ones, smaller ones, the kind with flat edges, etc.
      • try pens, skewers, or sticks

      What happens using these materials? What changes? What works best?






      Let us know what you did. Share your photos and results with us on Facebook, Twitter, Instagram, or send us an email to We love getting your messages!

      For more exciting experiments, check out our Yellow Scope Science Kits on the Shop tab of our website!


      elephant toothpaste logo | Yellow Scope blog



      Have you ever seen an elephant at the zoo or in the movies? Did you notice those big tusks? Those are actually two very large teeth.

      Imagine if elephants had to brush those teeth? They'd need a very large tube of toothpaste!

      In this month's 20 Minute Lab, we'll be using some household items to produce an exothermic chemical reaction. The result is a fun oozing foam - big enough to use as elephant's toothpaste!

      The main ingredient for this experiment is hydrogen peroxide - a common first aid supply. The hydrogen peroxide in your cabinet is probably a 3% solution, which will work just fine for the experiment. If you want a more powerful reaction, you can use 12% hydrogen peroxide, which you can find at beauty supply stores. If you decide to try the 12%, make sure you ask an adult to handle it. The adult should wear gloves, since 12% hydrogen peroxide can irritate the skin.


      • tray, plastic tub, or washable mat (You can use the one from your Foundation Chemistry kit if you have one!)
      • bottle with narrow neck
      • measuring cup
      • measuring spoons
      • hydrogen peroxide (standard 3% works, but 12% works even better)
      • food coloring (optional, but fun!)
      • dish soap
      • package of dry yeast (we used the measuring spoons, as we had bulk yeast)
      • water


      1. First, if you want to make it really seem like an elephant's toothpaste, you can cut a piece of paper to fit around your bottle and decorate it with markers or crayons to make it look like a toothpaste bottle! This isn't required for the experiment though, it's just for fun.
      2. Place your bottle on the mat or whatever you're using to catch the excess foam.
      3. Pour 1/2 cup of hydrogen peroxide into the bottle. (If you're using 12% hydrogen peroxide, have an adult do the pouring, perhaps using a funnel.)
      4. Add 8 drops of your favorite color food coloring.
      5. Add a good squirt of dish soap. Swirl to mix.
      6. Rinse out your measuring cup. Add 1 tablespoon of yeast and 3 tablespoons of warm water. Stir gently for about 15 seconds.
      7. Pour the yeast mixture into the bottle.
      8. Observe what happens!


      The red toothpaste was made using the standard 3% hydrogen peroxide.

      The blue toothpaste was made using 12% hydrogen peroxide! If you decide to use 12%, make sure to have an adult help and use gloves! (Note: We propped up the bottle a bit so the "toothpaste" squirted out to one side!)


      What's going on?

      formulas | Yellow ScopeDid you make an oozing foam? Why did this happen?

      The chemical formula for hydrogen peroxide is H2O2. This means it is made up of two hydrogen atoms and two oxygen atoms. Can you see how similar hydrogen peroxide, H2O2, is to water, H2O?

      If you left a bottle of hydrogen peroxide open to the air, over time it would slowly break down into water (H2O) and oxygen (O2). The oxygen would be released as tiny bubbles of gas that would dissolve into the air.  Eventually you would just be left with a bottle of water - but this would take a long time!

      Adding yeast dramatically speeds up this process.bread | Yellow Scope blog This is because a package of yeast contains "catalase". Catalase is an enzyme that speeds up the breakdown of hydrogen peroxide into water and oxygen.

      Note: When something speeds up a reaction it's called a catalyst. There are lots of different types of catalysts, but this one's easy to remember: catalase the catalyst!

      soap bubbles | Yellow Scope blogIn our experiment, the dish soap traps the oxygen gas (O2), which creates lots and lots of bubbles! All this bubbling makes the substance quickly expand and shoot out of the bottle.

      You might notice that your bottle is now a bit warm! That's because this chemical reaction produces heat. This type of reaction is called an exothermic reaction ('exo' means outside or external and 'therm' means heat).

      At this point what's left in your bottle in just soap, water and oxygen, so you can pour the remains of your experiment safely down the sink!



      Let us know what you did. Share your photos and results with us on Facebook, Twitter, Instagram, or send us an email to We love getting your messages!

      For more exciting experiments, check out our Yellow Scope Science Kits on the Shop tab of our website!


      20 minute lab lemon logo | Yellow Scope blog



      Ever wanted to make a super secret message to a friend, like you were a spy in the movies?

      top secret | yellow scope blogIn this month's 20 Minute Lab, we'll be writing a message using the "ink" of a common fruit!

      Planning to set up a lemonade stand this summer with your friends or family? In between customers, you can use the lemonade to write secret messages to each other!

      If you don't have a lemon or lemonade, you can use bottled lemon juice, an orange, lime, other citrus fruit, or even vinegar!


      egg supplies | Yellow Scope blog
      • half a lemon
      • small bowl
      • spoon and water
      • Q-tip
      • sheet of paper
      • a strong light bulb (100 watts), or an iron


      1. Squeeze about a tablespoon of lemon juice into the bowl.
      2. Add a teaspoon of water and mix with a spoon.
      3. Dip one end of the Q-tip into the lemon juice.
      4. lemon setup | Yellow Scope blogUsing the Q-tip like a pencil, write your message on the paper! (Note: Don't use too much lemon juice when writing each letter to avoid getting the paper too wet and warping it!)
      5. Depending on how long your message is, you may have to re-wet your Q-tip with lemon juice several times.
      6. Wait a few minutes for the paper to dry.
      7. light bulb | Yellow Scope blogNow hold your paper over the light bulb. (Note: incandescent bulbs work the best!) To use an iron, turn the steam setting to "off" and place a piece of fabric between the iron and paper. Have an adult help with this step!






      If you could see your message after the paper dried - without applying any heat - you may have used too much lemon juice when writing. Try it again - this time letting the Q-tip rest on the edge of the bowl before writing to let some of the liquid drip off.

      If your message does not appear after applying heat, the heat from the light bulb may not be hot enough. Try using a hotter light bulb or try the iron method.


      What's going on?

      Did your secret message magically appear? Did it turn dark brown? Why did this happen?

      Lemon juice is made up of carbon-based compounds, which you applied to the paper with the Q-tip. As you saw, it doesn't have any color at room temperature.

      However, heat breaks carbon bonds and sets some of those carbons free from the paper. When that free carbon contacts the oxygen in the air, it turns a brownish color. This process is called oxidation.

      lemon ink message | Yellow scope blog

      Sometimes substances will oxidize without any added heat. Have you ever had apple slices turn brown when they sit out for a while? That's because the carbon-based compounds in the apple oxidized without the need for the extra heat.

      apples | Yellow Scope BlogFun trick: to prevent your apples from turning brown, add some lemon juice to them! Lemon is a natural antioxidant which prevents the oxidation process from happening. 



      Let us know what you did. Share your photos and results with us on Facebook, Twitter, Instagram, or send us an email to We love getting your messages!

      For more exciting experiments, check out our Yellow Scope Science Kits on the Shop tab of our website!


      20 minute lab egg logo | Yellow Scope blog



      Got any leftover boiled eggs from Easter? How about using them for an experiment!

      ship in a bottle | Yellow Scope blogHave you ever seen a ship in a bottle? You may have asked, "How did they do that?" It may seem like magic, but really this trick is more painstaking work than a magician's slip of the hand.

      Most people just build the base of the ship outside the bottle with foldable masts. Then they slide it through and raise the masts inside the bottle with attached strings.

      What if you could suck the whole boat in at once? That would be pretty neat. Well, you can't do it with a boat, but you can with an egg! How? By manipulating the relationship between temperature and pressure. It's like magic but better - it's science!


      egg supplies | Yellow Scope blog
      • glass or hard plastic bottle
        (the mouth should be about a
        1/2 inch narrower than the egg)
      • 1 egg
      • small pot of water
      • folded strip of paper
      • match or lighter (with adult assistance)


      1. With an adult to help, place the egg into a small pot of water and bring it to a boil.
      2. Boil for 2 minutes, then let the pot sit for about 10 minutes. You now have a hard boiled egg!
      3. egg peel and position | Yellow Scope blogRinse the egg in cold water and peel off the shell.
      4. Place your egg, small side down, over the mouth of the bottle.
      5. Fold your paper so that it will easily fit through the mouth of the bottle.
      6. Have an adult light the  paper on fire.
      7. Quickly remove the egg, drop the paper into the bottle, and replace the egg over the mouth of the bottle. Watch what happens!


      What's going on?

      Wow! Was the egg pulled into the bottle? How did that happen? The key has to do with air pressure. Before the experiment, when the egg was sitting on top of the bottle, the air pressure inside the bottle was the same as it was outside the bottle. So nothing happens.

      pressure | Yellow Scope blogWhen you drop the burning paper into the bottle, the air quickly heats up and expands. Some of this expanding air pushes around the egg to escape. This is why you saw the egg vibrate and wiggle as the air whooshed past.

      When the flame goes out (once there was no more oxygen left inside the bottle to burn), the air inside the bottle begins to cool. Cool air contracts, which takes up less space and exerts less pressure.

      Because the egg acts as a seal, this sets up a difference in pressure - the pressure inside the bottle is less than the pressure outside the bottle. Air wants to move from high to low pressure. The higher air pressure outside pushes on the squishy, flexible egg until it is eventually pushed into the bottle.

      Physics is cool, right?


      thin bottle | Yellow Scope blogIf the bottle caved in instead and the egg wasn't sucked in, your bottle may be made of too thin a material. Try using a harder plastic or glass.

      If the egg breaks into pieces on the way in, it may have been too big for the bottle's mouth. Try a smaller egg or a larger-mouthed bottle.

      If nothing happened to the egg (it wasn't sucked into the bottle), the fire may have gone out as you dropped it into the bottle. Make sure the paper is fully lit and continues to burn when placed into the bottle.

      To get the egg back out again:

      1. Hold the bottle upside down, and move the egg around until the small end is resting in the mouth.
      2. Cover the bottle's opening with your mouth and blow, slowly but firmly, into the bottle. Then quickly point the bottle away from you.
      3. The egg should pop right out!

      egg blowout | Yellow Scope blog

      How does this work? By blowing into it, you increased the pressure inside the bottle. This increase in air pressure pushes the egg back out!

      boiled egg | Yellow scope blogGo ahead and eat your egg as a snack!



      Let us know what you did. Share your photos and results with us on Facebook, Twitter, Instagram, or send us an email to We love getting your messages!

      For more exciting experiments, check out our Yellow Scope Science Kits on the Shop tab of our website!

      20 minute lab logo | Yellow Scope blog

      Happy St. Patrick's Day!

      St. Patrick's Day is just around the corner - a time for Irish music, dancing, festivals and a lot of green. How about celebrating in your own home with some decorations made using science?!

      We can use household materials to make crystal shamrocks. Shamrocks are the leaf of a clover plant, and a symbol for the country of Ireland, where the real St. Patrick lived and is celebrated across the world today.

      NOTE: Though doing the lab will only take about 20 minutes, once you're done you'll have to wait overnight to see the full results.


      • green pipe cleanerShamrock lab materials | Yellow Scope blog
      • a large wide-mouthed glass jar
      • borax (powder found in the laundry aisle), about 1 cup
      • string
      • pencil (or pen, stick, straw)
      • boiling water

      NOTE: It is not safe to breath in or eat borax, so be careful. Don't worry, we've included some tips and steps that help you to stay safe!


      shamrock pipe cleaner | Yellow Scope blog
      1. Shape your pipe cleaner into a shamrock! Make sure it will fit into the jar's opening and that there's about a 1/2 inch of space on the sides. (You'll need space because the shamrock is going to get bigger.)
      2. Tie the piece of string around the stem of your shamrock.
      3. Hang your shamrock in the empty jar, suspending it right in the middle. Tie the other end of the string to the middle of your pencil. Remove the shamrock from the jar. jar and shamrock | Yellow Scope blog
      4. Then add water to the jar cup by cup. Count how many cups it takes to fill the jar.
      5. Now pour the water from the jar into a pot and have your parent bring it to a boil on the stove.
      6. Remove the pot from the heat and turn on the fan above your stovetop if you have one. If not, open a window or two for ventilation. 
      7. Wait until the water is calm and no longer bubbling. (You don't want to add borax while the water is still bubbling.) 
      8. Now add 3 tablespoons of borax for each cup of water. (For example, our jar held 6 cups of water, so we used 18 tablespoons of (3x6=18). NOTE: If you want to use cups to measure, there are 16 tablespoons in one cup.
      9. Mix the borax with a wooden spoon until it's completely dissolved. Be careful not to breathe in the steam.borax pour and stir | Yellow Scope blog
      10. Pour the water-borax solution back into the jar.
      11. Gently lower your shamrock into the jar so it's suspended right in the middle. Make sure it does not touch the sides or bottom of the jar, or it might get stuck there!
      12. Put the jar in an out-of-the-way place with good ventilation.
      13. Come back the next day to see what happened!

      shamrock crystal | Yellow Scope blog


      What's going on?

      You just made a shamrock crystal! A crystal is a special type of solid mineral in which the molecules fit together in an organized, repeating pattern. The process of crystallization is when molecules transition from chaos to uniformity!

      There are many different types of crystals found in nature, but crystals are generally formed in three ways.

      1. Some crystals, such as diamonds and emeralds, are formed when liquid rock (magma) slowly cools and hardens.
      2. Other crystals, such as snowflakes and frost, are formed when water evaporates (dries up) and the crystal is left behind.
      3. Still other crystals form when a supersaturated liquid that has a dissolved mineral in it, cools. The crystals in this experiment were formed in this way.

      Growing crystals from hot water:

      By heating the water, you were able to dissolve more borax than you could at room temperature because hot water molecules are farther apart so they have more space to hold borax. This is called a supersaturated solution.

      As the solution cooled, the water molecules moved closer together, so borax came out of solution (out of being mixed), and borax crystals started to form on the tiny bristles of the pipe cleaner.

      The size and shape of the crystals depends on how fast the solution cools. When solutions cool fast, smaller crystals are formed because they have less time to organize. Slow-cooling solutions tend to form larger crystals.

      Design Your Own Experiments


      • Try using food coloring in your water (maybe with a white pipe cleaner?)

      • What happens if you put the jar in the fridge instead of leaving it out?


      borax team | Yellow Scope blog

      Let us know what you did. Share your photos and results with us on Facebook, Twitter, Instagram, or send us an email to We love getting your messages!

      For more exciting experiments, check out our Yellow Scope Science Kits on the Shop tab of our website!

      glitter slime featured image | Yellow Scope slime recipe

      Let's Make Slime!

      Slime never ceases to fascinate kids, and it seems it’s all the rage again! Which is great news, because you can make slime right at home, and maybe even learn a little science while you’re at it!

      slime had | Yellow Scope slime recipeTurns out you can make slime with any number of household items. A big component of most recipes is glue. Good old Elmer’s Washable works just fine.

      All of these recipes are for one 'serving' of slime (not edible!) for one child. We find that 1/4 cup of glue makes a perfectly generous handful of slime (many websites call for a whole cup, but then your glue stock disappears!)


      Check all ingredients for anything that might be an allergen for your kids.
      Supervise to make sure your kids don't eat the slime (especially any containing borax).
      Wash your hands before and after making slime! Clean hands makes clean slime, and washing up after makes a clean you!

      Click on the icons to skip to the recipe of your choice:

      Crystal Clear Slime

      Glitter Slime

      Stretchy Slime

      Poofy Slime

      Floam (Crunchy) Slime

      Ooblek (Cornstarch) Slime

      1. Crystal Clear Slime

      clear slime product | Yellow Scope slime recipes

      Want the purest, clearest, snottiest slime there is? Try this recipe out for a glass-like finish to your new slime!

      What You'll Need:

      clear slime ingredients | Yellow Scope slime recipes

      • Clear Glue
      • Water
      • Borax Powder (in the laundry aisle)
      • Measuring Cup (1/4 cup)
      • Bowl
      • Spoon
      • Teaspoon

      A Note On Borax: Borax is a boron mineral and salt that comes right from the ground. It's often used as a laundry detergent enhancer or cleaner, but it is toxic if ingested in large amounts.

      Just handling it while playing with slime from this recipe won't cause any harm, but you might consider supervision to prevent ingestion. This is the only recipe that uses it.

      If you're still nervous, liquid starch works just as well - see Glitter Slime (makes for slightly stretchier slime too). Read about borax in slime from for more information.

      Let's Get Started!

      clear slime bowl | Yellow Scope slime recipe


      1. Pour 1/4 cup of clear glue into a bowl.
      2. Add 1/4 cup of water and stir. Set the bowl aside for a bit.
      3. To the measuring cup, add 1/4 cup of hot tap water.
      4. Add 1/4 teaspoon of borax powder to the hot water in the measuring cup. Stir until you can't see any little particles at the bottom.
      5. Add the borax and water solution to your bowl of glue and water. Slimetastic!
      6. Knead your slime to get a great texture.

      Note: if some of the liquid won't stir in, that's okay, just pull out your slime and dispose of the extra liquid.

      clear slime product | Yellow Scope slime recipe

      What's going on?

      Try experimenting with the slime a bit - move it around, poke it gently, poke it quickly... How does it behave? More like a liquid or more like a solid? If you think the slime seems like both a solid and a liquid, you're right! Some types of slime (and other mixtures like ooblek - see Recipe #6 below) can have qualities of both a solid and a liquid. Substances that can behave like a solid and a liquid at the same time are called non-Newtonian fluids. (Big word, right?!)

      How does it work?

      Glue is made of long molecules called polymers. Polymers are long chains of repeating units. These polymers can slide over each other, so glue flows like a thick liquid. When borax is added to glue, a chemical reaction occurs that causes cross-links, or bridges, to form between the glue molecules.

      This cross-linking of glue molecules is what creates slime. You may have noticed that if you leave the slime alone, it acts like a liquid and will mold to the shape of its container. This happens because the long slime molecules coil up and slide over each other.

      But when you apply pressure, this causes the molecular coils to unwind and get tangled up. This makes it harder for the slime to flow, so it feels more like a solid. Pretty cool, right? Now you know what a non-Newtonian fluids is! To learn more about these interesting materials check out this cool video from Crash Course Kids!

      2. Glitter Slime

      Let's get our glitter on! This is a very popular recipe.

      glitter slime yellow scope slime recipe

      What You'll Need:

      glitter slime ingredients | Yellow Scope slime recipes

      • Clear Glue
      • Liquid Starch (Purex Sta-Flo)
      • Glitter (or confetti!)
      • Water
      • Bowl
      • Measuring Cup (1/4 cup)
      • Spoon

      Let's Get Started!

      1. Add 1/4 cup of glue to your bowl.
      2. Add 1/4 cup of water and mix.
      3. Add glitter (don't be shy, add a lot!) and stir.
      4. Add 1/4 cup of liquid starch and watch the reaction before your eyes!
      5. Stir with the spoon until that becomes difficult, then use your hands.

      glitter slime product | Yellow Scope slime recipe

      Note: You can also add food coloring along with the glitter if you want some more color! Try other materials, like confetti, stars, or combinations!

      3. Stretchy Slime

      In it for the stretch? This is a very satisfying slime that takes a little more patience, but is well worth the wait.

      What You'll Need:

      • Glue
      • Eye Drops (we used Visine, but any brand should work)
      • Baking Soda
      • Food Coloring (optional)
      • Glass Measuring Cup
      • Spoon

      Let's Get Started!

      stretchy slime bowl | Yellow Scope slime recipe

      1. Add 1/2 cup of glue to the measuring cup.
      2. Add food coloring if you want to add color. Stir.
      3. Add 2 teaspoons baking soda and stir
      4. Add the eye drops 10 drops at a time, stirring after every set of 10, for a total of 50 drops. 
      5. Wet your fingers a bit with the eye drops and pick up your slime. It should still be a little sticky.
      6. Knead your slime by stretching and pulling.

      stretchy slime product | Yellow Scope slime recipe

      4. Poofy Slime


      This entertaining slime is made of shaving cream - and who hasn't wanted to play with shaving cream? The very act of spraying it into the bowl is a thrill for most kids.

      What You'll Need:

       poofy slime ingredients | Yellow Scope slime recipes

      • Glue
      • Foaming Shaving Cream (Barbasol works fine)
      • Baking Soda
      • Food Coloring (optional)
      • Saline Solution (contains both sodium borate and boric acid}
      • Measuring Cup (1/4 cup)
      • Bowl
      • Spoon
      • Tablespoon

      Let's Get Started!

      poofy slime bowl | Yellow Scope slime recipes

      1. Add about 2 cups of shaving cream into your bowl.
      2. Add food coloring if you want! (We used blue and yellow to make green)
      3. Add 1/4 cup of glue. Stir well.
      4. Add 1/4 teaspoon of baking soda.
      5. Add 1/2 Tablespoon of the saline solution. Mix like you're whipping cream (vigorously!)
      6. Remove and knead with your hands.

      At first the slime will stick to your hands quite a bit, but just keep kneading (for about one minute). Eventually  the poofy slime will come together and form a ball (and come off your hands)!

      poofy slime product | Yellow Scope slime recipes

      5. Floam (Crunchy) Slime

      Call them dragon eggs, frog eggs, or just spongy goodness, this is an easy experiment - it's basically the same recipe as glitter slime except with polystyrene beads. True confession: we didn't make this one ourselves, but our friends at Little Bins for Little Hands did - take a look at the fun they had!

      What You'll Need:

      floam slime ingredients | Yellow Scope slime recipes

      • Glue
      • Water
      • Liquid Starch
      • Polystyrene foam beads
      • Food Coloring (optional)
      • Measuring Cup (1/4 cup)
      • Bowl
      • Spoon

      Let's Get Started!


      1. Start by adding 1/4 cup of glue to your bowl.
      2. Add 1/4 cup of water and mix.
      3. Add food coloring (if you want!) and stir.
      4. Add the styrofoam beads - anywhere from 1/2 to a full cup - and stir.
      5. Add 1/4 cup of liquid starch and stir.
      6. Knead and stretch, it should be ready (not sticky) in about a minute!

      floam slime product | Yellow Scope slime recipes

      6. Ooblek (Cornstarch) Slime

      ooblek | Yellow Scope Slime RecipesHave you heard of ooblek? It’s that crazy material that you can make with just cornstarch and water. We mentioned ooblek in Recipe #1 above - it's another example of a non-Newtonian fluid. To learn more about these interesting materials check out this cool video from Crash Course Kids!

      If your child has never experienced ooblek, start by first making and experimenting with that:

      Ooblek: Mix 2 tablespoons cornstarch with 5 tablespoons water and blow their mind.

      You could call ooblek a type of slime, but it doesn't quite make the cut; you can't really hold it in your hand without it dripping all over.

      As fun as it is, you might have to go the extra mile and follow the glue recipe below to make it more traditionally slime-like. Let’s try it:

      What You’ll Need:

      ooblek ingredients | Yellow Scope Slime Recipes

      • Glue
      • Cornstarch
      • Food Coloring (optional)
      • Glass Measuring Cup
      • Tablespoon
      • Spoon
      • Surface Covering (like a plate, newspaper, etc, as this tends to get messy!)

      Let’s Get Started!

      As cornstarch tends to get everywhere, and this recipe tends to be finicky, we've outlined a fairly small sample size. Increase as desired!
      1. Measure out 1 tablespoon of glue and pour it into the container.
      2. Want to make it colorful? Add food coloring now!
      3. Add 2 tablespoons of cornstarch slowly, mixing as you add it. Watch it thicken!
      4. If you can pick up your slime and it’s not sticky or gooey, go to step 5. If not, add a little more corn starch.
      5. Pick up your blob of slime and knead it for a few minutes. You're done - have fun playing!
      Note: If the slime feels too dry, add just a tiny bit of glue. The consistency should be a bit like Play-Doh.

      ooblek product | Yellow Scope Slime Recipes


      Let us know what you did. Share your photos and results with us on Facebook, Twitter, or send us an email to We love getting your messages!

      For more exciting experiments, check out our Science Kits on the Shop tab of our website!


      little labs yellow scope


      Watching a rocket propel itself into space is one of the most exciting things to see. But did you ever wonder what makes it go?

      Well, yes, fuel of course. But fuel is only pushing against the ground. Why does the rocket move in the opposite direction, up?

      You might have heard this famous phrase before:

      "For every action, there is an equal and opposite reaction."

      That’s from Isaac Newton’s Third Law of Motion. This law helps us to predict how things will move.

      Wanna test this yourself? Let’s make a balloon rocket!


      • Yard stick/measuring tape
      • String
      • Balloon
      • Masking tape
      • Straight drinking straw
      • Data table on paper that looks like this:



        Distance Traveled


      You may also want a friend or parent to help as your lab partner!


      1. Blow up a balloon as big as you can. Pinch it off, but don't tie it closed.
      2. Wrap a piece of string around the middle of the balloon. (Your lab partner can hold the balloon closed while you wrap the string around it.)
      3. Measure the length of the piece of string. This is the circumference of balloon – or how big around the balloon is. Enter this length in the data table.
      4. Thread a long piece of string (10-15 feet) through the drinking straw.
      5. Attach the straw to the balloon with two pieces of masking tape.
      6. Attach one end of the string to a doorknob, a wall, or have your lab partner hold it.
      7. Pull the other end of the string tight and make sure it is level. Move the inflated balloon toward this end of the string.
      8. You're ready for launch! Let the balloon go and watch it fly like a rocket!
      9. Measure how far it went with your yard stick or measuring tape. Record the distance in your table.
      10. Now change the size of the balloon by blowing it up less, say half full, and repeat the steps. Try again with the balloon about a quarter full. Record your results in the table.


      What's going on?
      When you let go of the balloon, the air inside rushed out creating a force called thrust. Since the balloon is so light, the air is enough to propel (or push) the balloon forward.

      For every action, there is an equal and opposite reaction:
      Physicists call the air that came out of the balloon the ‘action force’ and the force that pushed the balloon forward the ‘reaction force’. When an action force goes in one direction, the reaction force goes in the opposite direction. The bigger the action force, the bigger the reaction force. This is why the balloon with most air in it went the farthest!

      With real rockets, thrust comes from the force of burning rocket fuel as it blasts from the rockets engine. As the engines blast down, the rocket goes up! Just as Newton predicted: “For every action there is an equal and opposite reaction.” In other words, when you push on something, it pushes back on you just as hard!


      Let us know what you did. Share your photos and results with us on Facebook, Twitter, or send us an email to We love getting your messages!

      For more exciting experiments, check out our Science Kits on the Shop tab of our website!