Category:Physics Experiments’

Soapy Science: Giant Bubbles

 - by KitchenPantryScientist

From surface tension to evaporation, science come into play every time you blow a bubble. Here’s some bubble science, along with a recipe for making giant bubbles from my book Outdoor Science Lab for Kids!

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Water molecules like to stick to each other , and scientists call this sticky, elastic tendency  “surface tension.” Soap molecules, have a hydrophobic (water-hating) end and (hydrophilic) a water-loving end and can lower the surface tension of water. When you blow a bubble, you create a thin film of water molecules sandwiched between two layers of soap  molecules, with their water-loving ends pointing toward the water, and their water-hating ends pointing out into the air.

As you might guess, the air pressure inside the elastic soapy sandwich layers of a bubble is slightly higher than the air pressure outside the bubble. Bubbles strive to be round, since the forces of surface tension rearrange their molecular structure to make them have the least amount of surface area possible, and of all three dimensional shapes, a sphere has the lowest surface area. Other forces, like your moving breath or a breeze can affect the shape of bubbles as well.

The thickness of the water/soap molecule is always changing slightly as the water layer evaporates, and light is hitting the soap layers from many angles, causing light waves to bounce around and interfere with each other, giving the bubble a multitude of colors.

Try making these giant bubbles at home this summer! They’re a blast! (It works best a day when it’s not too windy, and bubbles love humid days!)

To make your own giant bubble wand, you’ll need:

-Around 54 inches of cotton kitchen twine

-two sticks 1-3 feet long

-a metal washer

1. Tie string to the end of one stick.

2. Put a washer on the string and tie it to the end of the other stick so the washer is hanging in-between on around 36 inches of string. (See photo.) Tie remaining 18 inches of string to the end of the first stick. See photo!

This bubble wand is a little longer than 18 inches on a side.

This bubble wand is a little longer than 18 inches on a side.

For the bubbles:

-6 cups distilled or purified water

-1/2 cup cornstarch

-1 Tbs. baking powder

-1 Tbs. glycerine (Optional. Available at most pharmacies.)

-1/2 cup blue Dawn. The type of detergent can literally make or break your giant bubbles. Dawn Ultra (not concentrated) or Dawn Pro  are highly recommended. We used Dawn Ultra, which is available at Target.

1. Mix water and cornstarch. Add remaining ingredients and mix well without whipping up tiny bubbles. Use immediately, or stir again and use after an hour or so.

2. With the two sticks parallel and together, dip bubble wand into mixture, immersing all the string completely.

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3. Pull the string up out of the bubble mix and pull them apart slowly so that you form a string triangle with bubble in the middle.

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4. Move the wands or  blow bubbles with your breath. You can “close” the bubbles by moving the sticks together to close the gap between strings.

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What else could you try?

-Make another wand with longer or shorter string. How does it affect your bubbles?

-Try different recipes to see if you can improve the bubbles. Do other dish soaps work as well?

-Can you add scent to the bubbles, like vanilla or peppermint, or will it interfere with the surface tension?

-Can you figure out how to make a bubble inside another bubble?

Ten Environmental Science Projects for Earth Day 2020

 - by KitchenPantryScientist

Wednesday, April 22nd is Earth Day, but there’s no reason we can’t celebrate all month long. Besides hiking and exploring, here are some of our favorite environmental science projects. Just click on the experiment names for directions and photos. You can find more fun outdoor experiments in my books “Kitchen Science Lab for Kids” and Outdoor Science Lab for Kids (Quarry Books.)

Homemade Sweep Nets: Make a sweep net from a pillowcase and a hanger to see what arthropods are hanging out in your favorite outdoor spaces.

Homemade Sweep Nets from Outdoor Science Lab for Kids (Quarry Books)

Window Sprouts: Plant a bean in a plastic baggie with a damp paper towel to see how plants need only water and air to sprout roots and leaves.  Here’s a short video demonstrating how to make a window garden.

Window Sprouts from Kitchen Science Lab for Kids Quarto Books

Homemade Solar Oven: Using a pizza box, aluminum foil, plastic wrap, and newspaper, you can harness the sun’s energy to cook your own S’mores!

Nature Walk Bracelets: Wrap some duct tape around your wrist (inside out) and take a walk, sticking interesting natural objects like leaves and flowers to your bracelet. It’s a great way to get outdoors and engage with nature. Bring a bag along so you can pick up any trash you find.

Carbon Dioxide and Ocean Acidity: See for yourself how the carbon dioxide in your own breath can make a water-based solution more acidic. The project illustrates why adding too much carbon dioxide to Earth’s atmosphere can be harmful to ocean creatures.

Ocean Acidification Experiment from Kitchen Science Lab for Kids (Quarry Books)

Plant Transpiration:  See how trees “sweat” in this survival science experiment.

Plant Transpiration experiment from Kitchen Science Lab for Kids

Earthworm Experiment:  Do you know what kind of earthworms are living in your back yard?

Earthworm Eruption from Outdoor Science Lab for Kids (Quarry Books 2018)

Composting: Be a composting detective. Bury some things in your back yard (away from power cables) and dig them up in a few months to see how they look. Composting reduces methane gas emissions (a greenhouse gas) from dumps.

Composting Experiment from Outdoor Science Lab for Kids

Diffusion and Osmosis: See for yourself how the chemicals we add to water, put on our streets to melt ice, and spray on our lawns and crops can move into our soil, ground water, rivers, lakes and oceans.

Diffusion Experiment from Kitchen Science Lab for Kids (Quarry Books)

Solar Water Purification: This project illustrates the greenhouse effect and is a fun “survival science” experiment. Requires hot sun and some patience!

Solar Water Purification from Kitchen Science Lab for Kids

Citizen Science: Don’t forget about all the real environmental research projects you can participate in through Citizen Science programs all around the world!

For mores activities and games, check out NASA’s Climate Kids website, to see a kid-friendly diagram of the water cycle, click here or just get outside and enjoy the beautiful planet that sustains and nurtures us.

45 How-To Science Experiment Videos for Kids

 - by KitchenPantryScientist

Physics! Biology! Chemistry! Yeah!

Great job staying isolated to help keep everyone safe! Keep up the good work! Scientists and medical workers are busy testing anti-viral drugs and creating vaccines that will help us to help get life back to normal as soon as humanly possible. They are the superheroes we need right now!

Click HERE for 45 Watch-and-Do Videos for Kids. Some, like cornstarch goo and tie-dye milk are perfect for the younger crowd, while older kids can tackle the tougher projects.

For more detailed instructions, go to kitchenpantryscientist.com and search for the experiment in the search box! You can also order my books online wherever books are sold.

Marker Tie-Dye (KitchenPantryScientist.com)

15 Fun, Easy, Educational Science Projects to Keep Kids Entertained When Schools are Closed

 - by KitchenPantryScientist

Image from “Kitchen Science Lab for Kids” (Quarry Books 2014)

With a few simple pantry items, you can throw together some serious science fun. Here’s a list of project you can do using things from the pantry and craft drawer. Just click on the blue links for instructions!

Or, head outside to do some fun outdoor science!

You can find most of these projects on my Kitchen Pantry Scientist YouTube channel!

-composition book: Makes a great science notebook to draw, record, and tape photos of experiments into.

-clear plastic cups to use as test tubes and beakers
-measuring spoons and cups 
-school glue (white or clear) for making Mad Scientist’s Slime
-contact lens solution for making Borax-free Slime
-gummy worms to transform into Frankenworms
-baking soda: Can be used for a number of experiments like fizzy balloons, magic potion . Or just mix with vinegar to make carbon dioxide bubbles.
-vinegar Great for fizzy balloons , alien monster eggs and magic potion.
-balloons for fizzy balloons.
-dry yeast for yeast balloons.
-white coffee filters: can be used for magic marker chromatography, in place of a paper bag for a coffee-filter volcano or making red cabbage litmus paper.
-cornstarch:Lets you play with Cornstarch Goo, a non-newtonian fluid. Here’s the video.
-marshmallows with rubber bands and prescription bottle rings you have around the house can be used to make marshmallow catapults. My kids used theirs to make their own Angry Birds game.
-Knox gelatin and beef bouillon cubes can be used to make petri plates for culturing microbes from around the house. You can also use the gelatin for cool osmosis experiments!
-food coloring Helps you learn about surface tension by making Tie Dye Milk. Here’s the video. You can also easily make colorful sugar-water gradients that illustrate liquid density!
-drinking straws are great for NASA soda straw rockets and a carbon dioxide experiment.

If your kid likes to cook, is an artist or you want more ideas, you can order all of my science experiment books online at Amazon, B&N, Indiebound, or anywhere else books are sold! 

Happy Experimenting! 

Ice Science: Lifting an Ice Cube Using Salt and a String

 - by KitchenPantryScientist

Have you ever wondered why putting chemicals like salt on a road makes the ice melt?

To see how NaCl (table salt) melts ice by lowers the melting temperature of water, you’ll need an ice cube, a glass of water, and a piece of kitchen twine or string about 6 inches long and salt.

What to do:

Drop an ice cube in a glass of ice water.  Try to pick the ice cube up without your fingers by simply placing the string on it and pulling up.  Impossible, right?

From Kitchen Science Lab for Kids (Quarry Books 2014)

From Kitchen Science Lab for Kids (Quarry Books 2014)

Now, dip the string in water, lay it across the ice cube and sprinkle a generous amount of salt over the string/ice cube.  Wait about a minute and try again to lift the cube using only the string.  What happens?

From Kitchen Science Lab for Kids (Quarry Books 2014)

From Kitchen Science Lab for Kids (Quarry Books 2014)

It may seem like magic, but it’s only science. Watch me demonstrate the experiment by clicking here.

Salt lowers the temperature at which ice can melt and water can freeze.  Usually, ice melts and water freezes at 32 degrees Farenheit, but if you add salt to it, ice will melt at a lower (colder) temperature.

The salt helps the ice surrounding the string start to melt, and it takes heat from the surrounding water, which then re-freezes around the string.

Different chemicals change the freezing point of water differently.  Salt can thaw ice at 15 degrees F, but at 0 degrees F, it won’t do anything.  Other de-icing chemicals they add to roads can work at much colder temperatures (down to 20 degrees below zero.)  If it’s cold enough, even chemicals won’t melt the ice.

Brrr.

Pressure can also make ice melt at colder temperatures.  This is why ice skates glide on rinks.  The pressure is constantly melting the ice a where the blade presses down on it so the blade glides on a thin layer of water!

Supercool! Ice Science for Kids

 - by KitchenPantryScientist

Under the right conditions, purified water can get much colder than 32 degrees before it freezes into a solid. This “supercooled” water will instantly freeze when it touches an ice crystal.

You don’t need a special lab to make supercooled water. In fact, you can make it in your own freezer!

Image from Outdoor Science Lab for Kids (Quarry Books 2016)

1. Place three 12 oz bottles of water (caps loosened and re-tightened) in the freezer. Two should be filled with purified water and one with tap water.

2. Wait 2 hours and then check them every 5 minutes. When the tap water is frozen, gently remove the other two bottles from the freezer. (Tap water freezes first, because it contains some impurities that help ice crystals form more easily.)

3. Carefully open one bottle of purified water and pour it onto a few ice cubes on a plate. The supercooled water from the bottle will instantly crystallize into ice when it hits the cubes, making slush. Try it with the second bottle. There may be some freezing time variation between freezers, so you may have to experiment to find the perfect amount of time it takes your freezer to supercool water!

You can do the same thing by putting bottled water in a cooler full of ice, salt, and water. Salt lowers the melting temperature of ice, which makes the salty ice water cold enough to freeze bottles of liquid. Try the same experiment using soda to make a slushy! (From Outdoor Science Lab for Kids-Quarry Books 2014)

Image from Outdoor Science Lab for Kids (Quarry Books 2016)

Edible Science: Ice Cream Games

 - by KitchenPantryScientist

Ice Cream Keep Away (Outdoor Science Lab for Kids-Quarry Book 2016)

Ice Cream Keep Away (Outdoor Science Lab for Kids-Quarry Book 2016)

Brrr. It’s really cold here in Minnesota. Perfect for making ice lanterns by filling balloons with water and setting them outside the back door. I had a great time talking ice lanterns and homemade ice cream (an edible experiment in my new book) on WCCO MidMorning this AM. As promised, here’s the recipe for “Ice Cream Keep Away.” After all, it’s never to cold to eat ice cream.

Ice Cream Keep Away (from Outdoor Science Lab for Kids- Quarry Books 2015)

Materials

  • – 2 cups milk
  • – 2 cups heavy cream
  • – ½ cup sugar
  • –   2 Tbs. vanilla
  • –  quart or pint-sized plastic zipper freezer bags
  • –  gallon-sized zipper freezer bags
  • – 2 cups of rock salt or table salt
  •  -large bag of ice
  • -dish towels

Safety Tips and Hints

  • If the ice cream isn’t frozen when you check it, add more ice and salt to the outer bag and continue to throw it around for another five or ten minutes.
  • You make enough ice cream mix in this lab to make 4 ice cream footballs at a time, so there’s plenty of ice cream and fun to go around!

Step 1:  Make an ice cream mixture by combining 2 cups milk, 2 cups cream, ½ cup sugar and 2 Tbs. vanilla to a bowl and mix well.

Step 2.   Add one cup of ice cream mixture to a quart or pint-sized freezer bag, squeeze out some of the air and zip it closed.

Step 3.    Place the small bag of ice cream mixture in a second small bag, squeeze out the air and zip it closed as well.

Step 4.     Place the double-bagged ice cream mixture into a gallon-sized bag and fill the larger back with ice.

Step 5.    Pour a generous ½ cup of salt over the ice in the bag and zip the bag shut.

Step 6.    Wrap a dish towel around the bag of ice and place it in a second gallon bag. Zip the outer bag closed.

Step 7.   Play catch with the bag of ice and ice cream for ten or fifteen minutes.

Step 8.   Remove the bag of ice cream mix from the outer bag and enjoy your frozen treat.

Enjoy eating your frozen experiment! (From Outdoor Science Lab for Kids-Quarry Books 2016)

Enjoy eating your frozen experiment! (From Outdoor Science Lab for Kids-Quarry Books 2016)

The Science Behind the Fun:

 Making ice cream is a lesson in heat transfer and crystallization.

Water is the solid form of ice. When you add salt to ice, it lowers the freezing temperature of the water, melting it and allowing it to remain a liquid far below water’s normal freezing temperature of 32 degrees F (O degrees Celsius.)

 In this lab, adding salt melts the ice, making a really, really cold ice-salt-water mix. The icy salt water pulls, or transfers, heat out of the ice cream mixture, freezing the water molecules in the milk and cream into ice crystals.

Depending on how fast ice cream freezes and what ingredients it contains, the ice crystals will be different sizes. If you freeze the mixture very fast, you will probably get big ice crystals that make the ice cream grainy. Ingredients like gelatin encourage smaller crystals to form, making smoother frozen treats.  Adding emulsifiers like eggs to the mix helps the fats and water combine better, creating ice cream that thaws more slowly.  

  • Try added less salt to the ice to freeze the ice cream more slowly. How does this change the texture of the final product?
  • What happens if you add a Tbs. of gelatin to the mix?