Activities that you might want to try in your classroom (easy to obtain materials, and well tested)
Soda drink, extending to comparisons and graphing for older grades (note: need tall tubes for extension activities).
Glue. Free play for younger grades, quantitative assessment for older grades.
Landforms: building a mountain from a contour map.
My favourite activities to bring to classrooms
New favourite: building a mountain from a contour map.
Heat Convection lesson
Free play pulleys
Mixing solids and liquids free experimentation. Messy but effective. Make it quantitative for older grades.
Flower colour chemistry. Try in the spring with petals fallen from rhododendrons and roses.