Our lesson on chemistry started out with a review of basic terms (atoms, molecules, chemical reactions, etc.) Students learned about the difference between chemical reactions (which can’t be undone) and physical reactions (which can).
We then showed a couple of fun videos of chemical reactions: a video of an unfortunate gummy bear being added to potassium chlorate, and a video of elephant’s toothpaste. The elephant’s toothpaste in the video wasn’t kid-friendly, but some quick googling gave us a fun, kid-friendly version so we were able to make “baby” elephant’s toothpaste with the 9 Dots students!
We found good instructions at Steve Spangler Science and at this blog. In our experience, 6% hydrogen peroxide was impossible to find and unnecessary as well.. if you watch our video at the top of the post you’ll see that we got plenty of foam with just the 3%!
Next, students experimented with different liquids and ingredients that we disguised with food coloring, testing to see which reacted with each other.
In the picture below, Ana and Alondra find out what happens when you mix lemon juice and baking soda together! Scroll to the bottom for a complete list of ingredients the students experimented with.
- Our basic lesson plan is below:
Introduction:
Students will review basic chemistry concepts and learn about chemical reactions.
Materials:
For elephant’s toothpaste:
- hydrogen peroxide (many online instructions say 6% is necessary, but 3% worked perfectly fine for us and is easily found at grocery stores and drugstores).
- dry yeast
- food coloring
- water
- empty 16oz bottles (we used empty coke bottles because of the narrow neck)
- dish soap
- measuring spoons & cups
For testing for chemical reactions (feel free to mix and match your own ingredients):
- vinegar
- lemon juice
- baking soda
- sugar
- water
- food coloring
- small plastic cups
- spoons or craft sticks for stirring
- diet coke
- mentos
Handouts and Other Media:
Instructions for making Elephant’s Toothpaste. We used the instructions on this blog.
Preparation Time:
Approximately 20-30 minutes
Preparation Tasks:
Divide materials into individual sets for each table. We provided one set of ingredients for elephant’s toothpaste for each table, and then poured small cups of the different materials for testing at each table as well.
Project Time:
60-90 minutes
Lesson Plan Breakdown:
First, review the definitions of atoms (and protons, neutrons, and electrons), molecules, chemical reactions, and physical reactions with the students. Discuss the difference between chemical and physical reactions. We showed a couple of videos of chemical reactions; there are tons of cool choices on youtube.
Next, pass out project materials. Every group should start with the elephant’s toothpaste. Do not let students put the bottle cap back on the bottle after adding the yeast. It’s best that they put their hand over the top of the bottle and shake it, then quickly remove their hand. Point out to the students that this reaction is exothermic and releases heat – the bottle and the foam will be warm!
For the second experiment, students should try mixing the different materials set up at the table to see which ones react chemically and which react physically.
Lastly, we played some science jeopardy with categories of “plants & animals”, “chemistry”, “electricity”, and “9 Dots”.
