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Gift Guide Title Image | Yellow Scope Gift Guide 2018

Here’s a list of 15 science-themed gifts that have caught our eye this holiday season. From babies to tweens, there’s something for all the girls on your shopping list!

We've added links for online shopping, but we also encourage you to shop local. Most of these gifts can be found at your favorite neighborhood toy or book shop!



1. ABC What Can She Be? | Ages 2+
 ABC What Can She Be? | Yellow Scope Gift Guide 2018
From astronaut to zoologist, this brightly illustrated board book will let her know that it’s never too early to dream big!
$16.95 | your local bookstore
2. Caterpillar Gears | Ages 18 months+
Caterpillar Gears | Yellow Scope Gift Guide 2018
 Toddlers will love turning the interlocking gears to make the caterpillar crawl along the wooden board, all while building fine motor and problem-solving skills!
3. Bathtub Ball Track | Ages 3+
Bathtub ball track | Yellow Scope Gift Guide 2018
Endless fun for bathtub engineers! Younger kids will love pouring water through the track to see what happens. Older kids will enjoy building and reconfiguring different courses to test with the ball.
$19.99 |
4. Wooden Bug Blocks | Ages 2+
Bug blocks | Yellow Scope Gift Guide 2018
We love all the high quality, made-in-the USA block sets in the Uncle Goose line, and the bug set is no exception. The budding entomologist in your life will love the detailed close-up illustrations and you will appreciate the thoughtful design.
5. Quantum Physics for Babies | Ages 2+
Quantum physics for babies | Yellow Scope Gift Guide 2018
One in a series of board books written by physicist and father of four, Chris Ferrie, this book introduces basic concepts in physics to the very youngest of scientists, with a tongue-in-cheek style that adults will appreciate too!
$9.99 | your local bookstore


6. Magnetic Anatomy Puzzle | Ages 3+
Anatomy puzzle | Yellow Scope Gift Guide 2018
A great choice for the future anatomist or doctor on your list! This magnetic puzzle changes up the classic dress-up doll with 24 pieces, including internal organs, the skeleton, and the circulatory system.
7. Cubetto Coding Toy | Ages 3+
Cubetto Primo | Yellow Scope Gift Guide 2018
Meet Cubetto, the friendly wooden robot! Kids will love learning the basics of computer programming through hands-on play. No screens or reading required.
8. Bird Bingo | Ages 5+
Bird bingo | Yellow Scope Gift Guide 2018
For the littlest bird lover on your list, this beautifully illustrated set introduces 64 different bird species from around the world in a twist on the classic game.
9. Binoculars | Age 3+
Binoculars | Yellow Scope Gift Guide 2018 
A perfect first set for the budding naturalist in your life, these shock-proof binoculars from Kidwinz are outfitted with high resolution optics. They even come with a protective carrying case for field work!
$26.99 |
10. Electro Dough Kit | Ages 4+
Electro dough | Yellow Scope Gift Guide 2018
Explore circuit making with electric dough. This fun set from Tech Will Save Us includes six pots of dough, along with buzzers, alligator clips, and LEDs to bring imaginary doughy creature to life!


11. Paper Chromatography Kit | Ages 8+
Chromatography kit | Yellow Scope Gift Guide 2018
With Yellow Scope’s newest kit, kids will have a blast uncovering rainbows of color in plants, art supplies, candies and more using a super cool scientific technique. With art and creativity front-and-center, this kit will appeal to all kids, even those who may not realize they love science!
12. Smore Magazine | Ages 7+
Smore magazine | Yellow Scope Gift Guide 2018 
Ignite her brilliance all year long with a subscription to Smore, a science magazine that encourages kids to know more and be more!
From $29.99/year |
13. Boolean Box | Ages 8+
Boolean box | Yellow Scope Gift Guide 2018
Created by Boolean Girl, a non-profit organization with a mission to close the gender gap in computer science, this kit teaches girls to build their own computer and learn to code using SCRATCH, Minecraft and Python.   
$149.99 |
14. Women of NASA | 10+
Women of NASA | Yellow Scope Gift Guide 2018
This 231-piece Lego set includes mini-figures of four pioneering women of NASA – astronomer Nancy Grace Roman, computer scientist Margaret Hamilton, and astronauts Sally Ride and Mae Jemison – along with instructions to build the Apollo Guidance Computer, the Hubble Space Telescope as well as the Space Shuttle Challenger.
 15. Cytosis Game | 10+
Cytosis game | Yellow Scope Gift Guide 2018 
Launched as a wildly popular Kickstarter project, Cytosis is a board game that takes place inside a human cell. Players compete to build hormones and enzymes all while fending off attacks by viruses!

Yellow Scope | Five Empowering Halloween Costumes for Girls

There’s nothing wrong with a princess costume - but some girls may want to trade their tiaras for a cape or beaker! It can be hard to find empowering costumes at your local Halloween pop-up, but the interest is there, and more girls are dressing up as strong female leaders.

We’ve scoured the internet for inspiring costumes ideas and found many ready-to-wear and DIY costume options that are easy, unique and powerful!


Yellow Scope Lab Coat | Empowering Halloween Costume For Girls | Scientist

We’d be lying if we said we didn’t think everybody should dress up as a scientist at least once in their life, and Halloween is the perfect time. Yellow Scope’s white lab coat can be easily accessorized with a pair of safety goggles

The lab coat includes a cute embroidered yellow microscope that reminds her of her awesome science powers and signals to others that a laboratory genius has entered the room.

From now through October 31st, enter HALLOWEEN15 at checkout for 15% off anything from our website!


Yellow Scope Empowering Halloween Costume for Girls | Olympic gymnast

She was gliding across the kitchen floor in her socks during the Winter Olympics figure skating competition and she dreams of someday competing for TeamUSA. Award her with a gold medal costume this Halloween.

Liz at Say Yes offers easy steps to create your own Olympic Gymnast costume which can be easily tailored to her favorite sport whether it’s basketball, tennis or skiing!  



Yellow Scope Empowering Halloween Costume for Girls | Rockford Peaches

Keeping with the sports theme, who doesn’t love A League of Their Own? Your daughter can celebrate her love for baseball by dressing up as a Rockford Peach.

A Mighty Girl is an awesome online collection of smart and empowering books, movies, toys and more. Their Rockford Peach costume is officially licensed and features many of the same details seen in the movie including league patches, belt, dress, and baseball cap. Complete the costume with her favorite worn-in baseball glove.



Yellow Scope Empowering Halloween Costume for Girls | Supergirl

Leaping typical costumes in a single bound, your daughter will be well on her way to being a girl of steel in this Supergirl costume by Chasing Fireflys.

The costume is comfortable and made of high-quality materials and includes a sparkly dress, cape and a strong gold belt. You can also purchase cool matching boots to complete the look.



Yellow Scope Empowering Halloween Costume for Girls  |  Rosie the Riveter

Our WWII heroine, Rosie the Riveter, is one of the most popular and beloved Halloween costumes for powerful girls and it can be easy to put together at home with a pair of denim pants and jacket. If you need a little help you can purchase the denim shirt, embroidered "Rosie" patch, and handmade polka dot headband from The Silver Closet on Etsy.

There are lots of people pulling out their sewing machines to create exciting new costumes every day. This “Empowering Girl’s Costume” Pinterest board has lots of great ideas like Lt. Judy Hopps, Alice Paul, an astronaut or an arctic hunter. We hope these ideas inspire you to discover your favorite female role model. Share your costume creations with us on our Facebook page.

Candy corn and moonlight - wishing you a happy Halloween night! 


Let us know how your costumes turned out. Share your photos  with us on Facebook, Twitter, Instagram, or send us an email to We love getting your messages!

Team Yellow Scope!

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!


      yellow scope blog | stem summer activities


      Summer, glorious summer! A time for relaxing, vacations, and unplugging... We’re several weeks into summer, and if your family is anything like ours, that last one might be a challenge. As an antidote to too much screen time, we’ve put together a list of STEM-based activities.

      Not only will these activities help prevent the summer learning slide, they’ll also encourage kids to put down those screens for a bit. That’s what we call a win-win!

      Some of the activities involve apps and online research. You can mix and match to strike a healthy balance between hands-on activities and educational online resources.


          Yellow Scope | Summer STEM | Acids and Bases kit

          Does making elephant toothpaste, fizzy lemonade, or invisible ink sound fun? Check out these free resources for these and more exciting experiments:

          At home: Check our Yellow Scope’s 20 Minute Labs for a series of quick and fun hands-on experiments! Sign up for our email list and follow us on Facebook and Twitter for new labs every month.

          Send your kids to “camp”! Our Camp Yellow Scope  is a digital series of eight chemistry-based experiments, including printable instructions and worksheets to hypothesize, record, and analyze data.

          Online: There are some excellent online STEM resources to keep kids engaged. Check out Nova labs  from PBS. They cover topics ranging from cybersecurity to the sun.

          Science kits: If you are looking for convenience and real science equipment, consider everything-in-the-box science kits such as Yellow Scope’s Foundation Chemistry Kit or Acids, Bases & pH Kit. Your local library may also have science kits that can be checked out for free!

            2. GET OUT IN NATURE

              Yellow Scope | Summer STEM | Nature Walks

              Explore the natural world! Keep your eyes open and be curious.

              Identify plants: Learn the names of the plants in your own backyard or at your local park with the online projects like YardMap, or apps like PlantSnapp and Garden Answers.

              Take a hike: Hiking is not only good exercise, but can also stimulate your brain! Check out rock formations, birds’ nests, insects, and plants. Carry an inexpensive magnifying glass to get closer to nature. Bring along paper and markers to draw what you observe!

              Be a bird detective: Use this guidebook from Bird Sleuth to explore the world of birds in your neighborhood.

              Yellow Scope | Summer STEM | Stars, galaxies, meteor showerStars, galaxies, and more: Visit a local observatory to learn more about our universe. Keep a track of astronomical events that you can observe in your region even without a telescope.

              Mark your calendars for the Perseid meteor shower in August. Check out these other spectacular 2018 astronomical events. NASA is another great resource of online activities for kids.

              3. STEM BOOKS AND GAMES


              science books | Yellow Scope blogOnline: PBS and National Geographic are great resources for online STEM games for kids.

              Library: Check out STEM books or participate in STEM programs at your local library.

              STEM games: Check out these cool games that will keep your kiddos (and you!) busy for hours: Snap circuits junior, Lego Chain Reactions, Gravity Maze and Math for Love Prime Climb

              Subscribe to STEM magazines: Kids love getting mail! Consider a subscription to a STEM magazine. There are some great ones our there: SMORE, National Geographic, MUSE, or Strong Magazine.


                  Yellow Scope | Summer STEM activities | Frontiers for Young Minds- kids review science

                  It’s true! There’s a science journal out there for kids. Real scientists submit papers there that are then reviewed by kids. If your kids are interested in learning more about scientific research and review process, sign them up for Frontiers for Young Minds. (for ages 8-15).

                  5. MUSEUMS AND MOVIES

                  Yellow Scope | Summer STEM | Science Museum

                  Museums and science centers: Go visit your local science and technology museums. Explore the exhibits and participate in STEM activities there. 

                  Movie night!: Grab the popcorn and queue up a science-themed Hollywood movie, such as Hidden Figures, Apollo 13, or The Martian. (Common Sense Media provides ratings and excellent descriptions of movies to help you determine if the subject matter is appropriate for your child.)


                  SHARE WITH US!

                  Let us know how your activities turned out! Did you identify a new plant or read any STEM book? Share your summer STEM photos and videos with us  on FacebookTwitter, or Instagram. We love getting your messages!

                  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.

                  WHAT YOU’LL NEED

                  • 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

                  LET'S GET STARTED

                  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?

                  molecules | 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!

                  SHARE WITH US!


                  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!

                  WHAT YOU’LL NEED

                  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

                  LET'S GET STARTED

                  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. 

                  SHARE WITH US!


                  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


                  SHIP IN A BOTTLE vs EGG IN A BOTTLE

                  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!

                  WHAT YOU’LL NEED

                  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)

                  LET'S GET STARTED

                  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!

                  SHARE WITH US!


                  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!