Science- Week 4

Topic: Endothermic vs. Exothermic

Before discussing what endothermic and exothermic is, I talked a little bit about chemical reactions and ways to classify them. We also discussed, with examples, the difference between a physical change and a change of substance. Thinking back to our gumdrop molecules, I reminded the children of how the toothpicks represented the binds that are formed to create a molecule. When a chemical reaction happens, and a new substance if created, these binds are created or destroyed, and the atoms that were initially present are rearranged and form new molecules. 

The four signs of a chemical reaction that we talked about in class were:

*change of color

*formation of gas

*formation of a precipitate

*change of temperature

The change of temperature is where endothermic and exothermic came in. Since an endothermic reaction happens when the reaction absorbs energy, I told the kids to think of the energy going "indoors" since it also sounds like "endo". If the reaction gives off energy, and send the heat out, I told the children to think of "exit" for "exo". 

The children were then able to conduct three different experiments of mixing things together and watching for a chemical reaction. We mixed baking soda and vinegar, damprid and baking soda water, and then epson salt with water. 1st-4th grade had a worksheet to fill out and keep track of the reactions. We did not have time to answer the questions on the bottom, so please have your child complete that portion at home.