This experiment gives students hands-on experience with scientific investigation as they mix various solids (flour, sugar, epson salt, and baking soda) with vinegar to determine the best solid-liquid mixture to make a gas. Students will predict what they think will happen, collect data as they follow instructions, and then draw a conclusion and determine whether or not their prediction was correct.
It can be done whole-group, with partners, or individually. It's basically the fun "mix baking soda and vinegar to make an eruption" activity... I've just added the paperwork to make it primary-age-scientific! And my Kindergarteners L-O-V-E-D making the volcano around their cup. I think yours will, too!