1. Rainbow bottle production: Preparation materials: transparent glass bottle, food coloring, water, food oil, detergent. Experimental steps: First, add a small amount of water to the bottle, then add a few drops of different colored food coloring and shake evenly to form a colored water layer. Then slowly pour in the cooking oil, as the oil and water are immiscible, the oil layer will float on top of the water. You can try adding a small amount of detergent to the oil and observe how it helps colors spread in the oil layer, creating a rainbow like effect.
2. Volcanic eruption simulation: Prepare materials such as baking soda, vinegar, red food coloring, dishwashing liquid, large plastic bottles, small bottles or paper cups as volcanic craters, soil or sand to shape the volcanic body. Experimental steps: Pour half a bottle of vinegar into a plastic bottle and add a few drops of red food coloring. Mix baking soda with a small amount of dishwashing liquid and pour it into the volcano. Finally, aim the crater at the vinegar in the plastic bottle, quickly pour the baking soda mixture, and observe the phenomenon of "volcanic eruption", that is, foam and liquid mixture are ejected from the crater.
3. Non Newtonian fluid production: Preparation materials: corn starch, water, large bowl, spoon. Experimental steps: Pour an appropriate amount of corn starch into a large bowl, then slowly add water while stirring with a spoon until a viscous paste is formed. At this point, what you get is a non Newtonian fluid that can be as hard as a solid and flow like a liquid. Try quickly tapping the surface of a non Newtonian fluid with your palm to feel its "hard" counterattack, then slowly insert your hand into it to experience its fluidity.