Question

which is the best working model to make in a science fair

Answer 1

Things Required ·        
1/2 cup water ·        
1/4 cup vinegar ·        
1/4 cup dish detergent ·        
Red or orange food coloring ·        
2 tablespoons baking soda ·        
Tissue
Steps: 
1.    Build your volcano model. Use a container in the center to hold liquid. This container can be an old water bottle, soda bottle with the top cut off, or even a simple glass jar.
2.    Add water, vinegar, dish detergent and food coloring. Do not add your baking soda at this stage.
3.    Add the baking soda when you are ready for an eruption. Wrap the baking soda in a tissue and drop into the volcano. The baking soda will react with the vinegar and cause the eruption.