Place a small mound of sand on a heat-proof surface.
Press your finger into the top of the mound to create an indentation large enough to hold half a golf ball.
Pour 5 teaspoons of rubbing alcohol into the dent.
Gently mix 1 teaspoon of baking soda with 4 teaspoons of sugar in a separate bowl. Pour the mixture into the dent on top of the rubbing alcohol. Stir the mixture gently without making the mound collapse.
Light the mound with a match by touching the flame to the mixture at the top of the mound. A "snake" will start to grow from the mound.
Mix rubbing alcohol and baking soda in a small bowl. Add a marshmallow to the bowl. Have the students record what they see happening to the marshmallow in their journals after a few minutes.
Repeat Step 1, but this time soak one marshmallow in rubbing alcohol and another in baking soda. Ask the students to note in their journals what happens after a few minutes.
Combine rubbing alcohol and baking soda with other substances, such as vinegar, and keep repeating the experiment. Ask the students about their observations afterward, and discuss why the marshmallows reacted differently with different substances.
Add 1 tablespoon of baking soda to one bowl, 1 tablespoon of baking soda to another bowl, and 1 tablespoon of some other substances, such as vegetable oil, vinegar, lemon juice or dish soap, to some other bowls. Put just one substance in each bowl.
Submerge a dirty penny in each bowl for 24 hours.
Rinse each penny with water.
Have the students record in a journal which substances did the best job at cleaning the pennies, and discuss why that is the case.