Sodium alginate (Say it like you say algae!) is a substance found in the cell walls of brown algae, including seaweeds and kelp. Its rubbery, gel-like consistency may be important for the flexibility of seaweed, which gets tossed around on ocean waves.
Here on dry land, you can use sodium alginate to make edible balloon-like blobs that are liquid in the middle. We can thank scientists for this delicious project, since they discovered that a chemical reaction between sodium alginate and calcium causes the alginate to polymerize, or form a gel. In this experiment, the gel forms on the outside of a sodium alginate blob, where the chemical reaction is taking place. The inside of the blob remains liquid!
No heat is required for this experiment, making it safe and fun for all ages!
Sodium alginate and calcium lactate can be tricky to find at the grocery store, so you’ll probably have to order them online. But they’re not very expensive, and you’ll have lots of fun playing with them!
-a blender or hand blender (parental supervision required for small children)
-1/2 tsp sodium alginate
-2 tsp calcium lactate
-flavored drink drops, like Kool-Aid or Tang (optional)
You can try making these with juice, but if there is any calcium in the juice, you may end up with foam in your blender, since it may start to polymerize the sodium alginate when you blend it in.
- Add 1 and 1/2 cup water to the blender.
- To the water, add 1/2 tsp. sodium alginate.
- Blend for about a minute, and let rest for 15 or 20 minutes, until the bubbles are gone.
- If you want to add flavor, divide the sodium alginate solution into small containers and stir in the flavor, like a squirt of Kool-Aid liquid.
- Add 4 cups of water to a clean, clear glass bowl or container.
- To the water, add 2 tsp. calcium lactate and mix until completely dissolved. This is your calcium lactate “bath.”
- Fill a spoon, like a tablespoon, with the sodium alginate solution, and slowly lower it down into the calcium lactate bath. You’ll see a gel begin to form. Gently turn the spoon so the sodium alginate falls off the spoon and into the calcium lactate.
- After about 30 seconds, you’ll be able to see a pale blob in the water. Leave it there for three or four minutes. You can make several edible balloons at once.
- When the blobs are ready, use a spoon to carefully remove them from the bath and put them in a clean bowl of water for a few seconds to rinse them off.
- Put your edible balloons on a plate and taste them. What do you think?
Now that you know how to polymerize sodium alginate with calcium, what else could you try? Can you make a foam in the blender? Can you make gummy worms in the bath using the rest of your sodium alginate solution? Can you invent something entirely new??? Try it!
Thank you to Andrew Schloss’s book Amazing (Mostly) Edible Science for the experiment inspiration! Adding the Kool-Aid and Tang drops to add a little flavor and color was our idea!
Spring is egg season. You may prefer dyed eggs, hard-boiled eggs, deviled eggs, or even dinosaur eggs. No matter what kind of eggs you like best, you’ll love these eggsperiments that let you play with the amazing architecture of eggs, dissolve their shells and even dye them with the pigments found in your refrigerator. Just click on experiments for directions and the science behind the fun!
Did you know you can use science to make amazing works of art in Jell-O? I created this experiment to make Star Wars Jell-O, but you can take it in whatever direction you want. Remember, you’ll need agar, lots of Jell-O and some coconut milk to start experimenting! If your agar figures break, you can fill in the cracks with more melted agar! I ordered the silicone Star Wars molds on Amazon.com.
Here’s the science part: Agar is a substance extracted from the cell walls of red algae. It’s often used in cooking and science experiments. Agar has a higher melting temperature than the gelatin used to make Jell-O. So, if you put a piece of agar gel into melted Jell-O, the agar won’t melt unless the Jell-O is really hot (about 150 degrees Fahrenheit or 65 degrees Celsius!) That means you can create works of agar art to embed in your favorite Jell-O. We used silicone molds, cookie cutters and a molecular gastronomy technique called oil spherification to make our agar decorations. To make the orbs using spherification, you simple drip coconut milk agar through cold oil, forming perfect spheres that solidify as they fall. We talked with Astronaut Abby on Kare11 Sunrise about how you could make these orbs in space. Click here to see the segment.
Vegetarians like to eat agar, since it’s made from algae and not animals. In labs, scientists use agar to make petri dishes for growing microorganisms, since it won’t melt at high temperatures in incubators. They also use it to make gels for electrophoresis, to separate DNA and RNA molecules by size!
*If you want to make white orbs from the coconut milk agar, you’ll need to plan ahead and chill tall jar or glass of vegetable oil in the freezer until it is thick and almost frozen. You’ll also need some squeeze bottles or clean eyedroppers.
Coconut Milk Agar -To create your white decorations and mini orbs, mix up this coconut milk agar dessert.
2 1/2 cups water
4 Tbs Agar flakes from Asian section of grocery store or COOP
1 cup coconut milk (not lowfat) Mix the coconut milk well before you measure it.
4 Tbs. sugar
In a sauce pan or the microwave, heat 4 Tbs. agar in 2 and 1/2 cups water until the agar is completely dissolved. Adult supervision required.
To the agar mixture, add 1 cup coconut milk and 4 Tbs. sugar. Mix Well. Pour into molds, pour into a pan to cut shapes out with cookie cutters, or pour some into a squeeze bottle to make white orbs.
Coconut Milk Orbs (optional cool science experiment
Slowly drip melted coconut milk agar (above) through ice-cold vegetable oil. As it fall through the oil, it should harden and form orbs. Collect the orbs with a slotted spoon and rinse before adding to your Jell-O.
Follow the directions on the package for the speed set method. If you make a double batch, pour half of it into the bottom of a large, glass casserole dish or bowl. If it’s a single batch, pour the whole thing in. If you made coconut milk orbs, put some in the melted Jell-O to see whether they float or sink. Let the Jell-O solidify and arrange your agar decorations on the Jell-O.
Make or remelt more Jell-O. When it’s cooled down a bit, pour it over your decorations to trap them in the Jell-O. You may want to leave them sticking out a little, or cover them completely with Jell-O over them for effect.
What else could you try? What Jell-O masterpiece can you create?
There are few gifts that are more fun (and less expensive) than a homemade science kit. Give a kid a bottle of vinegar and a box of baking soda and you’ll make their day. Throw in a bottle of Diet Coke and some Mentos mints, and you may be their favorite person ever. Make a kit for your kids or grand kids. Make one for your favorite niece or nephew. Encourage kids to make kits for friends and siblings. Make one for yourself!
When kids do science at home, there are no rules, there are no time limits, and no one is judging their results. It’s the perfect opportunity for them to explore, make guesses about what will happen and try new things. In other words, they’re learning to be creative. What could be better than that?
Below are some ideas for great items to include in your kit. I’ve highlighted links to the experiments on my website (just click on the blue experiment name) in case you want to print out directions to add to your kit.
You can also find these experiments, and more, in my book Kitchen Science Lab for Kids (available wherever books are sold online and in stores), on my free KidScience app for iPhones/iPads/iPods and 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 for making Mad Scientist’s Green Slime
Borax detergent to use as a cross-linker for the Green Slime
gummy worms to transform into Frankenworms
baking soda: Can be used for a number of experiments like fizzy balloons and magic potion. 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 experiment
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!
Mentos mints will make a Mentos geyser when combined with a 2L bottle of Diet Coke.
drinking straws are great for NASA soda straw rockets and a carbon dioxide experiment.
Here are some great last-minute experiments to make your Halloween more fun and spooky! Watch the TV segment I did to see how much fun they are, and look for links to directions below the video.
Click on these links for instructions on how to make Frankenworms, Cornstarch Goo, Mad Scientist’s Green Slime, Alien Monster Eggs, Magic Potion and Bags of Blood. You can find more experiments by scrolling down on my website!
Write spooky messages for your friends with invisible ink! Just paint lemon juice on printer paper with a Q-Tip, let it dry and reveal the message using heat from a candle flame via oxidation! Adult supervision is required when using candles. You can also reveal your message using a very hot light bulb, but we had better luck with a flame.
You can see how it looks in the segment below. We also dusted for fingerprints on glasses with chalk and cocoa powder to get ready for the Science Museum of Minnesota’s upcoming Sherlock exhibit.
Here’s how to make them!
Find written directions by clicking here.
Summer surrounds us with science. We’ve been catching tadpoles and capturing caterpillars and releasing them as frogs and butterflies. It’s nothing short of amazing to watch these creatures move through a process called metamorphosis, which changes them from one form to a completely different one as they become adults. This is a great survival tactic, since the youngsters and adults live in different areas and eat different things, so they’re not completing for food or space!
You can look for monarch caterpillars on milkweed and swamp milkweed, which you see in the video above. Bring plenty of food home for them to eat as they grow (the plants you found them on.) Tiger Swallowtail Caterpillars prefer a diet of dill! If you have trouble finding caterpillars, plant some milkweed and other butterfly-friendly flowers in your garden! The monarch population is in trouble due to lack of milkweed, which once grew everywhere. Click here for more information raising Monarchs.
We caught tadpoles in a local fountain (with permission, of course) and brought them home to observe. When they became tiny toads, we released them in the same fountain where we caught them. Before catching tadpoles, check local regulations to make sure it’s allowed and ALWAYS return them to the exact spot where you caught them, to avoid the spread of deadly fungi and invasive species! If you can’t return them to the same spot, don’t bring them home! Keep them in water from the source where you caught the them, and never add tap water to their habitat, since chlorine will kill them. Be sure there is a rock for them to crawl onto when they become frogs or toads. They’ll eat water plants and algae from their original habitat, but you can also boil green lettuce in bottled water and chop it finely to feed your tadpole. Release them immediately when they hop out of the water, since it may be difficult to know what to feed them once they’re mature.
Between working on a follow-up to Kitchen Science Lab for Kids (which involves testing, writing up and photographing 52 experiments), driving my kids around to camps and sports, and doing science outreach at libraries, bookstores and on TV, I’m finding it hard to keep up. Here’s a short video on how to make tie-dye milk (a surface tension experiment), which I did on WCCO Mid Morning show last week and forgot to post!
Luckily, between all the camps and activities, the kids and I are having fun digging in the dirt, blowing giant bubbles, and watching tadpoles and monarch caterpillars go through metamorphosis!
What science experiments are you doing this summer? It’s a great time to take science outdoors!
Here are some of our favorites:
Hungry? Build a solar oven from a pizza box and bake s’mores.
Stand on eggs or throw them as hard as you can without breaking them. You can always clean up mistakes with your hose!
And no summer would be complete at our house without an epic marshmallow shooting competition. You’ll even learn some physics!
Every fossil has a story to tell.
Whether it’s the spectacular specimen of a dinosaur curled up on it’s eggs or a tiny Crinoid ring, mineralized remains offer us a snapshot of the past, telling us not only what creatures lived where, but about how they lived and the world they inhabited.
Growing up surrounded by the flat-topped, windswept Flint Hills of Kansas, it was hard to imagine that I was living in the bottom of an ancient seabed, but there was evidence of the Permian period all around.
Now, when my kids and I return to my hometown, a fossil-hunting trip is always part of our routine, and we hunt for shells and coral where roads cut through crumbling limestone and and chert (flint.) Looking up at layer after layer of rock and shells, I can almost feel the weight of the water that once covered the land.
An episode of RadioLab we heard on the drive North from Kansas to Minnesota explained that coral keeps time and that by comparing modern coral to ancient coral fossils, scientists discovered that millions of years ago, years were about 40 days shorter than they are now. Can you guess why? Give the podcast a listen here. My mind was blown!
A visit to the Flint Hills Discovery Center in Manhattan, KS gave us more insight into the amazing geology, ecology and anthropology of the Flint Hills and the Konza Prairie that blankets them. Most people don’t know that the great tallgrass prairies of the United States wouldn’t exist if not for humans, who have been burning them for thousands of years.
What do you know about where you live? What’s it like now? What do you think it was like long, long ago? Are there fossils nearby?
Here are some fossil-hunting resources I found online, in case you want to go exploring: