Let’s Get Cooking! DISCOVERING: What ingredients come together to form CHEMICAL and PHYSICAL CHANGES?
Things are heating up in our cafeteria! Students …. We have a problem! Our cafeteria workers have VANISHED, and all of their recipes have disappeared with them! All we can find are these books with strange recipes. We need YOU to help us prepare these things so we can feed the students today. Look in these books and see if you can make any sense of it!
What do you mean, “The recipes are STRANGE?” Well, class, it says right here on this recipe to “use raisins and flour to make a physical change.” And then later it tells us to “cause a chemical change to occur.” Physical and Chemical Changes? Didn’t we just read about that in Science class? Yes, and it says on today’s outline that we’re going to watch a video about it today. Let’s watch it now! We will watch the video, class, but first let’s review what we learned yesterday. Can someone tell me the definitions of Chemical Change and Physical Change?
Physical Change: A change in the size, shape, or phase of matter, without the matter changing chemically. Chemical Change: The process by which the substances present at the beginning of the change are not present at the end; new substances are formed. The change cannot be “undone.” Definitions Melting ice <From bread to burnt toast Pencil Sharpened Rusted Nail>
Now, Let’s Watch the Videos! Click here to see the United Streaming Video on Matter and Its Properties. You will need to use your username and password to get in! Click here to see the Brain Pop Video on Chemical and Physical Changes.
Earn your kitchen pass! Now that you’ve learned even more about the differences in Chemical and Physical Changes, you MAY be able to help us figure out these recipes in the kitchen! Let’s see what you know… Answer these questions, and you will earn a kitchen pass. **Type your answers to the following questions in the boxes provided. 1. What is the definition of a chemical change? 2. What is the definition of a physical change? 3. Give 2 examples of a physical change. 4. Give 2 examples of a chemical change.
Not done yet…. One more quiz! Take quiz here! Go to this quiz site and test your knowledge!! Now, you can go on and create your very own kitchen pass, so the cooking can begin!
Create Your Kitchen Pass! Name: Age: Homeroom Class: Certified Kitchen Pass Enter your information above, then insert a photo of yourself into your pass! Congratulations! You may now enter the food service area!
What Seems to Be the Problem? Well, it’s these recipe books!! Instead of giving clear and concise directions, they are giving instructions to create physical and chemical changes! Can you PLEASE help?? • 5. After physically changing your eggs, add it to the yeast mixture and mix to blend well. • Turn out onto a lightly floured surface and knead for about 10 minutes, until dough is smooth and elastic. • Place dough in a lightly buttered bowl, turning once to grease the surface. • Cover with a clean dish cloth, and let stand in a warm place until doubled in bulk, about 1 ½ hours. • Physically change the dough by punching it down and dividing into 2 portions. • Cover and let rest for 10 minutes. • Shape into 2 loaves; place in 2 greased 8x4x3 in. loaf pans. Raisin Bread INGREDIENTS: 1 package active dry yeast 1/4 cup warm water 1 cup raisins 1/4 cup soft butter 1/4 cup sugar 1 1/2 teaspoons salt 1/2 cup scalded milk 3 3/4 cups all-purpose flour 2 eggs, beaten • Create a chemical change with the yeast and warm water. • In a large bowl, make a physical change with raisins, butter, sugar, and salt. • Add hot milk; stir to dissolve the sugar. Let the mixture cool to lukewarm. • Stir in 1 ½ cups of the flour; beat well. p.2 p. 1
How’s Your Recipe Coming? Raisin Bread Recipe Continued… Okay… now let’s decode the recipe. • Cover and let rise again for about 45 – 60 minutes, until almost double. • Chemically change the dough at 375° for 25 minutes, placing foil over loaves the last 10 minutes, if the loaves are physically changing too much. • Remove loaves from pans and let cool on racks. 1. Why does the first instruction ask for a chemical change? 2. What is instruction number 2 telling you to do? p. 3 3. Why is this a physical change? Alright! You’re good to go! You can go ahead and start cooking!
Let’s Check Something Out… • Why does yeast undergo a chemical change when mixed with warm water?? • Place a small amount of dry yeast on the slide and examine. Take notes and draw what you see on your investigation sheet. • Place a small amount of yeast & water mixture on the slide and examine. Take notes and draw what you see on your investigation sheet.
COULD YOU MAKE YOUR OWN MIXED-UP RECIPE? With your partner or group, select one of the recipes from the following link, and change the directions to match what you found in the cafeteria’s mixed up recipes. Choose a food that you would enjoy eating. Write your recipe on the recipe card given to you.
Which are examples of physical changes? Forming clay into a pot Let’s See…
Teacher Page: Title of Lesson: Chemical and Physical Changes: What’s what in the kitchen? • GLEs and Lesson Plan Objectives: • 9. Sort objects using one characteristic (PK-CS-P2) (PS-E-A1) • 11. Describe properties of materials by using observations made with the aid of equipment such as magnets, magnifying glasses, pan balances, and mirrors (PK-CS-P4) (PS-E-A2) • 13. Compare the properties of different solids and liquids through observation (PK-CS-P1) (PS-E-A4)
Now That You’re Done… You may write in your journal about your experience as a cafeteria worker. Be sure to note the ways you could tell which steps required a physical change, and which steps required a chemical change.