We had a great time playing with dry ice on WCCO TV this morning. I showed viewers how to make spooky Halloween decorations (hot water, food coloring and dry ice), carbonate beverages, inflate a balloon, and even make a spoon “sing.”
Dry ice is literally really cool, which is why you have to wear gloves to handle it. It’s made from frozen carbon dioxide gas, and as it warms up, it goes from the solid to liquid state instantly, skipping being a liquid altogether in a process called sublimation. As it becomes a gas, it cools water molecules in the air around it, making fog. And if you add it to a liquid, it carbonates the liquid with bubbles.
To make dry ice, you have to get carbon dioxide gas really cold and put it under pressure so that it goes instantly from the gas phase to the solid phase in a process called deposition. Here’s a video of a machine that makes dry ice pellets:
One of the best things about doing science in the summer is that you can take the mess outdoors, and clean it up with a hose. So what are you waiting for? Grab the baking soda, vinegar, food coloring, cornstarch and balloons and head outside for some instant off-screen fun. Share photos of your experiments on Twitter and Instagram using the hashtag #ScienceMess!
Here are some ideas to get you started, but you can find lots more on this website and in my new book Outdoor Science Lab for Kids!
Sidewalk Frescoes with Cornstarch Goo
Solar Heat Beam
Have fun experimenting! And don’t forget to clean up your mess!
This summer, get off screens and get outside!
Outdoor Science Lab for Kids: 52 Experiments for the Yard, Garden, Playground and Park hit real and virtual bookshelves this week! To celebrate, I’m posting this video we took a few weeks ago of one of my favorite experiments from the new book.
Can’t wait for your copy of the book to arrive before you try this out? Here’s how to make water rockets.
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)
- 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!
Spring break is right around the corner!
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.
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)
- – 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.
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?
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!