# Slides 6.7: Quick Bread Science Lab Slide outline for Lesson 6.7. Nineteen slides across two days: Day 1 slides 1 to 10, Day 2 slides 11 to 19. Slide 6 is the treatment table and it stays on the board all of Day 2. [Sal: photograph the four muffins in a row at the end of Day 2. That photo is the review slide for items 9 and 10 on the Cooking Methods Check.] * * * # DAY 1 ## Slide 1: Quick Bread Science Lab - Unit 6, Lesson 6.7, Day 1 - Topic 6.2 Food Preparation Methods and Science - Four batches, one difference - This is an experiment, not a recipe Image: four muffins in a row, visibly different heights, cut in half. ## Slide 2: Do now - A muffin and a loaf of bakery bread both rise - Do they rise the same way? - Write yes or no and one guess about what makes each one rise Notes: Take four answers, correct none. A student who says "yeast" for the bread has half the concept already; give them the Batch E stretch. ## Slide 3: Watch this Image: a clear cup with baking soda, and a hand pouring vinegar into it, foam climbing over the rim onto a tray. Notes: This is the hook. Do it live, with no warning. Then: "That gas is what lifts a muffin. Today you figure out exactly which ingredient makes it." ## Slide 4: How leavening works - Baking powder and baking soda both make carbon dioxide gas in a wet batter - The gas makes bubbles - The bubbles get trapped and push the batter up - The heat sets the batter around them, so it stays up after it cools Image: a cross-section drawing of batter with bubbles rising through it. ## Slide 5: The difference between the two - **Baking powder** already has its own acid mixed in. Water and heat are enough - **Baking soda** has no acid of its own. It needs an acid in the recipe - Acids in a real kitchen: buttermilk, yogurt, vinegar, lemon juice, brown sugar, cocoa - No acid means the soda mostly sits there and leaves a soapy taste Notes: Students mark which one needs the acid. ## Slide 6: The four batches | Batch | Treatment | |---|---| | A (control) | 1 tsp baking powder | | B | none at all | | C | 2 tsp baking powder | | D | 1 tsp baking soda, no acid | Notes: This slide stays on the board for all of Day 2. Everything else in all four batches is identical. ## Slide 7: The four-cup fizz test - Cup 1: baking soda plus water - Cup 2: baking soda plus vinegar - Cup 3: baking powder plus water - Cup 4: baking powder plus vinegar Notes: Run all four in order and call the result out loud each time. Then ask the class to state the rule from the evidence, not from the slide. ## Slide 8: Variable and constants - **Independent variable:** the one thing we change on purpose. The leavening - **Dependent variable:** what we measure. Height, crumb, taste - **Constants:** flour, sugar, salt, milk, oil, egg, batter per liner, oven temperature, bake time, same oven, same shelf - The control batch is the ruler. Without it, the other three mean nothing Notes: [Sal: ask the science teacher which words they use for independent and dependent variable and use theirs instead of these. It is free and it makes both classes stronger.] ## Slide 9: Predict - One prediction per batch - Rank the four by expected height - Plus one sentence: what will Batch D taste like, and why? Notes: Predictions are written before any batch exists, so they cannot be adjusted after. Collect nothing; the sheet comes back tomorrow. ## Slide 10: Tomorrow - Roles on your card - Four bowls, labeled A, B, C, D - **I dispense the leavening, not you** - Exit card: the one thing we are changing is ___. Batch ___ will rise the highest because ___ Notes: Say the leavening rule out loud today so it is not a surprise tomorrow. One student adding baking powder to Batch B ends the experiment. * * * # DAY 2 ## Slide 11: Bake, Measure, Conclude - Unit 6, Lesson 6.7, Day 2 - Four bowls, one difference, no cheating - Whatever comes out of that oven is the answer Image: four labeled mixing bowls in a row on a station counter. ## Slide 12: Do now - Read your prediction for Batch B - Do you still believe it? Yes or no, one sentence Notes: Thirty seconds. Then: "Whatever comes out of that oven is the answer, and it is not up for a vote." ## Slide 13: The six-step routine - Hair back - Sleeves up - Wash hands - Sanitize surfaces - Clean as you go - Station check before dismissal Notes: Same six steps, same order, every lab all year. Start the timer when every station is standing with hands empty. ## Slide 14: Mix, in this order - Dry ingredients measured and **leveled** into the labeled bowl - I come around with the leavening - Wet added: milk, oil, egg - Stir about **fifteen strokes and stop.** Lumps are fine - 1/4 cup of batter into each labeled liner Notes: Overmixing makes tough batter and it confounds the test. Say "fifteen strokes, lumps are fine" at every station, once. ## Slide 15: The flowchart ``` Minute: 0 5 10 13 20 25 28 35 40 Mix: |======four batches=======| Bake: |===13 min===| Measure: |before| |after, crumb, taste| Clean: |as you go |ZONES| ``` Notes: Measure the before height while the batches wait. I load and unload the oven; nobody else touches it. ## Slide 16: What to measure - Height, with the ruler, before and after - Crumb: split one open. None, few, or many holes - Taste, if you choose to. Own fork, own plate Image: a ruler held against a split muffin, with the rise marked. ## Slide 17: A warning about Batch D - It will taste soapy or metallic to most people - Nothing is wrong with you - That taste **is** the evidence Notes: Say this before anyone tastes. Students who are not warned decide something is wrong with them or with the food. ## Slide 18: Conclusion frame - The data showed ___ - My hypothesis was supported / not supported / partly supported, because ___ - My evidence is ___ - One thing that could have gone wrong is ___ Notes: Take two conclusions out loud. Batch C often rises highest and then collapses; that is the best data in the room and not a mistake. ## Slide 19: Station check - Oven off, tin on the trivet - Four bowls washed, dried, put away per the map - Counters wiped and sanitized, sink empty - Floor swept, trash out - Leavening jars back on my table Notes: When I sign a station, the Station Manager reads the station's one-sentence conclusion out loud. Lab sheets collected at the door. Keep one muffin from each batch under wrap for the review.