CHEMICAL & PHYSICAL CHANGES 5th Grade Physical Science Pumpkin Bag With your shoulder partner, take 2 minutes to draw a pumpkin face with a Sharpie on the bag. RULES: • BE CAREFUL TO NOT RIP YOUR BAG! • Do not play with the substance inside your bag. • Leave the label on the outside of the bag. Pumpkin Bag 1. Observe powder in the plastic bag and the liquid in the cup. 2. Take the cup with liquid in it and put it in the zipper sandwich bag (that contains the powder) WITHOUT dumping it. 3. Seal the zipper bag tightly. 4. Make a prediction: What do you think will happen when the two substances mix? Pumpkin Bag 5. Keeping the zipper part of your bag at the top, dump the cup of liquid into the sealed bag. 6. Swirl the bag around, taking turns holding the bag. Pumpkin Bag USE YOUR 5 SENSES TO OBSERVE THE BAG How does it feel? How does it sound? How does it look? Can you smell anything? (Please don’t taste it!) What changes are taking place? How have the contents of your bag changed? Physical or Chemical Change?? Based on your observations, predict which one is a physical change and which one is a chemical change. TELL YOUR SHOULDER PARTNER YOUR PREDICTION. Bag Popping: Physical Change OR Chemical Change? Pumpkin Bag: Physical Change OR Chemical Change? WHY!?!?!?!?! Physical Changes A type of change that involves the physical properties of a substance. Matter keeps its identity. • Includes: changes in position change of volume change of shape change of state of matter Physical Changes • Example: Falling raindrops can freeze to form sleet. Explanation: Raindrops and sleet differ in size, shape, volume, and phase of matter, they are both still the same essential substance: water. Can you think of another example? Chemical Changes Process by which substances are changed into different substances with different properties. Matter becomes NEW MATTER! When a chemical change occurs, atoms rearrange themselves to form different kinds of matter. Chemical Changes • Example: A ship’s wheel is made of the element iron. After years of being in the ocean’s water, the iron on the wheel’s surface changed into a new material called iron oxide. Iron + Oxygen = Iron Oxide Can you think of another example? Evidence of Chemical Changes • Change in Color • Formation of Gas or Solid • Fizzing/Bubbles • Crystal Formation • Temperature Change • Change in Odor • Change/ Release of Energy • Combustion (the process of burning) Remember this? When a chemical change occurs, atoms rearrange themselves to form different kinds of matter. What do we call this? Chemical Reaction: Process in which new substances are formed during a chemical change. Chemical Reactions NaHCO3 + C2H4O2 (Baking Soda) + (Vinegar) NaC2H3O2 + CO2 + H2O (Sodium Acetate Trihydrate) + (Carbon Dioxide) + (Water) REACTANTS PRODUCTS (A substance that takes part in and undergoes change during a chemical reaction.) (Substance(s) created during a chemical reaction) Chemical Reactions NaHCO3 + C2H4O2 NaC2H3O2 + CO2 + H2O How many elements do you count in the REACTANTS? PRODUCTS? How many atoms of elements do you count in the REACTANTS? PRODUCTS? DO YOU NOTICE A PATTERN?? Law of Conservation of Mass Matter cannot be created or destroyed in a chemical reaction. The total mass of the matter before and after a physical or chemical change remains the same. WANT TO SEE ME PROVE IT?? What’s Next? • Science Notebook Page • Evidence of Chemical and Physical Changes • Law of Conservation of Mass • Chemical and Physical Change Practice • Coach Workbook Lesson 18 • Read Page 95 – 97 with your activity partner • Discuss the Discussion Question on page 98 with your activity partner • Complete questions 1 – 4 on page 98 INDEPENDANTLY & PROVE-IT!
