I talked summer science with Ira Flatow and Lynn Brunelle on Science Friday (NPR)! We swapped ideas for water rockets, pitfall traps and leaf paint, among other fun things. You can visit Science Friday’s website and listen by clicking here!
From “Outdoor Science Lab for Kids” (Quarry Books 2016)
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.
Edible Water Balloons- KitchenPantryScientist.com
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 liquid drink drops to add flavor and color (KitchenPantryScientist.com)
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.
Gently turn the spoon upside down.
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.
After a few minutes, you’ll see a pale blob.
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.
Rinse balloons off in water.
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!
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 videodemonstrating how to make a window garden.
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!
Carbon Dioxide and Ocean Acidity: See for yourself how the carbon dioxide in your own breath can make a water-based solution more acidic. It’s the same reason too much carbon dioxide in Earth’s atmosphere can be bad for our oceans.
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.
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.
Solar Water Purification: This project illustrates the greenhouse effect and is a fun “survival science” experiment. Requires hot sun and some patience!
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.
Here’s a video from my YouTube channel on how to do this experiment, so kids can “watch and do.”
To play with permanent marker tie dye, you’ll need:
-permanent markers (like Sharpies)
-cotton items to decorate, like tee-shirts, socks, or dish towels
-rubbing alcohol (isopropanol)*Read warning labels. Parental supervision is required, since rubbing alcohol is poisonous if swallowed. Do this experiment in a well-ventilated area, and do not expose your artwork to heat until is is COMPLETELY dry, since rubbing alcohol and its fumes are flammable.
-containers like plastic cups or jars
To make your designs, stretch the cotton over the mouth of a jar or cup and secure it with rubber bands. (See video above.)
Use permanent markers to make several dime-sized dots of different colors on the stretched cotton.
Slowly drip rubbing alcohol onto the spots of color until the alcohol starts to soak outward, carrying the ink with it.
Allow your design to dry overnight. When completely dry, hang your shirt in the sun, or put it in the dryer for 15 minutes to set the color. Wash separately from other clothes, just in case!
The Science Behind the Fun: Pigments are molecules that give things color. The pigments in permanent markers are trapped in ink compounds that are insoluablein water, which means that they won’t dissolve in water. However, if you add a solvent, like rubbing alcohol, or isopropanol, to permanent markers, it dissolves the ink. As the alcohol moves through the cloth you are decorating, it carries the pigments along with it. Small pigment molecules move faster than big ones, so the colors sometimes separate into their different color components as they move through the cloth. The alcohol evaporates into the air, leaving the ink in the fabric, and since it is still insoluable in water, it won’t come out when you wash it.
Enrichment: What happens if you draw lines, concentric circles or different shapes on your designs? Can you layer colors and watch them separate? What if you add rubbing alcohol next to the color, instead of directly on it? How many drops of alcohol do you have to add to a dime-sized color spot before it starts to expand?
As I was trying to think of a science experiment to do with Peeps, I remembered seeing a marshmallow puff up to twice its normal size in a vacuum chamber, which was pretty cool.
Since I don’t have any way to create a mechanical vacuum at home, I decided to try using a wine pump to inflate a peep and discovered that it is extremely hard to get a Peep into a wine bottle. Even the bunny Peeps are too big to push in without maximum destruction!
So, I went bottle hunting and found that Smucker’s syrup bottles and Martinelli’s apple juice bottles have big enough mouths to accommodate Peeps of the chick or bunny variety, but still work with wine pumps. Here’s what happened!
To puff up a Peep, you’ll need
-a clear, empty bottle that fits both a Peep and a wine pump (see above.)
-a wine pump with a matching rubber vacuum cork
-Peeps (or marshmallows)
Pumped Up Peeps- KitchenPantryScientist.com
Put a Peep or two in the bottle. If it’s sticky, coat the sticky spot with a little bit of sugar. Try to squish it as little as possible when pushing it into the bottle.
Put the rubber vacuum cork in the bottle to form a tight seal.
Pump air out of the bottle until your Peep has grown as much as possible
Release the vacuum to see it shrink back to normal size.
The Science Behind the Fun:
Peeps contain corn syrup, gelatin and food coloring, but they are mostly made up of air bubbles. The air trapped in the bubbles is at atmospheric pressure. When you pump air out of the bottle, the pressure in the bottle drops. Gases expand under lower pressure, and the air in the marshmallow bubbles is no exception. The bubbles expand inside the stretchy corn syrup and gelatin (get bigger), making the Peep puff up.
Oil and water don’t mix, which comes in handy for this fun science experiment! Play with density and chemical reactions when you try this foaming, bubbling experiment that uses an effervescent tablet like Alka-Seltzer to make carbon dioxide bubbles ooze up through a thick layer of oil. (Adult supervision required, since Alka-Seltzer contains aspirin.)
Fill a bottle 1/4 full with water or vinegar*. Add food coloring (or red cabbage juice) to the water or vinegar.
Fill the bottle almost to the top with vegetable (or other) oil. Note how the oil floats on the water, since it’s less dense.
Optional: Add cut-up plastic Easter basket grass, glitter, plastic beads, or other items you think might float on the water layer, but sink through the oil.
Finally, add an effervescent tablet to the liquid in the bottle and watch the chemical reaction. When the citric acid and sodium bicarbonate (baking soda) in the tablet react with the water and each other, they make something new: carbon dioxide gas, or CO2. The CO2 bubbles carry some of the colorful liquid up through the oil with them, but the dense liquid quickly sinks back down to the bottom.
*Vinegar reacts with the sodium bicarbonate the Alka-Seltzer, making extra carbon dioxide bubbles!
For a fun variation, put a balloon over the top of your bottle after adding the Alka-Seltzer to trap the carbon dioxide gas and inflate the balloon. If the balloon looks like it’s about to pop, remove it from the bottle.
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!
Here are three experiments that will appear in my upcoming book Outdoor Science Lab for Kids (Quarry Books, June 2016) to keep get kids off screens and into some science. Click on the experiment name to go to my original blog post, instuctions and more about the science behind the fun.