Here are some things that I, (89 D) learned in this unit. I learned about something called a exothermic Reaction. I had never knew that there was such a thing! An exothermic Reaction is a Chemical reaction in which more energy is given off  than there is being taken in. That is an   I also learned about acids. An acid is a compound that releases hydrogen ions in water. An acid can be very dangerous, too. Some of them can burn right through your skin, or if you eat some of them, you will die. But you CAN eat citris acid. It is found in limes, lemons, oranges, and apples. There are many acids, too. Such as citric acid, stomach acid, vinegar, orange juice, soda water, AND drinking water. We also did an experiment with acids and bases. We mixed two substances together and it made a hot purple substance. I loved that experiment! I had alot of fun doing stuff about heat and matter, acids and bases, and everything else. I hope that we do something like that again!