Why is it that solid ice can turn back into liquid water, but a cooked egg can't turn back into a raw egg? Or why can you stir sugar into your coffee or tea, but you can't stir it back out? It's enough to drive you mad! To answer this question you will need to put on your detective hat and solve the mysteries of physical and chemical changes. If that doesn't sound interesting, well... watching some things explode and creating your own Mentos and soda volcano should help.
what you’ll need
- A computer, tablet, or mobile phone and access to the internet
- Pens, crayons, markers, or colored pencils
- A bottle of soda
- A package of Mentos
Ask About Today
Name one chemical change and one physical change that took place to make dinner. How do you know this happened?
Imagine if everything in the kitchen was as highly reactive as Mentos and soda. What two things would you try combining first? What kind of reaction would they create?
Skip the Ads
Unfortunately, online videos often start with short advertisements. Remind your campers to click the "Skip" button as soon as they can to move ahead to the video.
Investigate the Branches of Chemistry
Before we start, let's get our chemistry straight. You might think of "chemistry" as a single type of science—one that involves combining different kinds of liquids together in funny-shaped glasses and tubes. But there are actually many different types of chemistry, like "analytical chemistry," which is what a real chemical detective would do, and "nuclear chemistry," which focuses on the changes and reactions of atoms. Which branch do you find most interesting?
Exploring Chemical Reactions
Hey chemical detectives! Today, you'll learn the differences between physical and chemical changes and be able to answer the question, "Why can solid ice turn back into liquid water, but a cooked (solid) egg can't turn back into its raw (liquid) form?" Weird, huh? Let's check in with Bill Nye to explain this and many more mysteries.
Remember: Online videos often start with advertisements. (Annoying, we agree!) Click the "Skip" button as soon as you can to move ahead to the video.
Let's Watch Things Explode
Chemical reactions are anything but boring. When combined, some substances can explode at the touch of a feather, burst into flame, or grow strange smoky tentacles. Click on the various videos on this site to see a few especially exciting chemical reactions in action.
Don't try these at home: These reactions are dangerous! Don't try them at home—you'll hurt yourself and probably ruin the kitchen.
Make a Mentos + Soda Volcano
Here's some mad science you can do at home. You'll need at least one bottle of soda, a package of Mentos (those little mints that come in a roll), and some space outside or a bathtub where things can get messy. (Younger kinda campers will also need some help from an adult.)
Start by watching this video to see one girl's own Mentos and soda experiment. Then, try it yourself! Be sure to drop in the Mentos as quickly as you can, and stand back. If you have a few different types of soda, see which one produces the most extreme reaction.
What's Going on with those Mentos Anyway?
Why do Mentos and soda create such a strong chemical reaction? Read this article from Science Sparks to learn more.
Is It Physical or Chemical Change?
Today's experiment involved a very fizzy kind of chemical change. There are plenty of other examples, though, and they're different from "physical" changes (like crushing a Mento with a hammer, instead of dropping it in soda). Today, we’ll explore those differences so that you can notice them in you daily life. Be sure to click “Learn More” at the end!
For younger explorers
Women in Chemistry
Follow along with children's librarian and author Phoebe Fox as she reads Women in Chemistry.
What's Your Little Alchemy Score?
How many Little Alchemy combinations have you found so far? Were any of them surprising to you? We found 32 so far but are aiming for 50 today!
For younger explorers
Sort the Substances!
Let's go back into the lab with Sid The Science Kid. Head on over to PBS Kids and play Sorting Box!
Time to Get (Re)Active
Chemists are always on the go, and you need to be able to keep up! Here’s another workout video to keep you in tip top shape with our favorite gym teacher, Joe.
more to explore
Actual Chemical Detectives
Crime scene investigators like the ones you see on TV use chemistry everyday to identify substances and help solve crimes. Learn more about what they do and how the reality of their work differs from what you tend to see on screen.
More Chemical Reactions in Action
Let's face it, chemical reactions are pretty cool. Combining two things to create something new feels a little like magic. Take another look at the science behind chemical reactions in this Good Thinking! video from the Smithsonian.
Kitchen chemistry is a real thing. Watch this video from Crash Course Kids to see how our favorite food, cake, involves a chemical reaction.