In the reaction of hydrogen peroxide and potassium iodide, the solution quickly rises which shows the formation of gas. This means it is a chemical reaction.
The beaker/test tube/whatever you used should also become warm because it is an exothermic reaction. This means its a chemical reaction
The top one is different from the bottom because of is curvature shape while the bottom one is a square shape i think the bottom will heat up faster because of the nice even area inside where heat waves can evenly flow
