Student Exploration: Plants and Snails

Transcription

1 Name: Date: Student Explratin: Plants and Snails Vcabulary: brmthyml blue (BTB), carbn dixide-xygen cycle, indicatr, interdependence Prir Knwledge Questins (D these BEFORE using the Gizm.) 1. What imprtant gas d we take in when we breathe? 2. Why dn t we run ut f the imprtant gases that we need t stay alive? Gizm Warm-up In the Plants and Snails Gizm, each f the test tubes cntains water and a small amunt f brmthyml blue (BTB). BTB is a chemical indicatr. An indicatr changes clr when the chemicals in the water change. 1. With the lights set t n, drag a snail int ne test tube and a plant int anther. Press Play ( ). After 24 hurs, what is the clr f each tube? 2. Select Shw xygen and CO 2 values. Place the O 2/CO 2 prbe in each tube. The prbe will shw yu the levels f tw gases, xygen (O 2) and carbn dixide (CO 2), in the tubes. We call these amunts the gas levels. A. When the water turns blue, which gas is mst cmmn? B. When the water turns yellw, which gas is mst cmmn? C. What des it tell yu when the water is green?

2 Activity A: Gases in and gases ut Get the Gizm ready: Click Reset ( ). Clear all f the test tubes. Turn n Shw xygen and CO 2 values. Questin: What gases d plants and animals take in and what d they give ff? 1. Cllect data: Use the Gizm t learn what gases plants and animals take in and give ff. Try it in bth light and dark. Recrd yur results belw. If yu d mre than five experiments, write yur extra results in yur ntebk r n separate sheets f paper. What is in the tube Lights: n/ff Results 2. Analyze: Study yur data n gases given ff by plants. A. What gas d plants give ff in the light? B. Hw abut in the dark? 3. Analyze: Study yur data n gases given ff by animals. A. What gas d animals give ff in the light? B. Hw abut in the dark? C. Hw d these results cmpare t yur plant results? 4. Infer: Describe the carbn dixide-xygen cycle by cmpleting the sentences belw: Animals breathe in and breathe ut. In sunlight, plants take in and release.

3 Activity B: Interdependence Get the Gizm ready: Click Reset. Clear all f the test tubes. Turn the light switch t n. Check Shw xygen and CO 2 values. Questin: Hw d plants and animals depend n each ther? 1. Observe: Put ne sprig f Eldea and ne snail in a test tube with the lights n. Click Play. A. Des the clr f the water in the tube change? B. What happens t the O 2 and CO 2 levels? 2. Predict: Withut using the Gizm, predict what yu think will happen t the gas levels in each case listed belw. (Leave the Actual result clumn blank fr nw.) Tube Predictin Actual result 2 snails, 2 sprigs, lights n 1 snail, 2 sprigs, lights n 1 snail, 2 sprigs, lights ff 3. Run Gizm: Nw run the Gizm t test yur predictins. Recrd yur findings in the table. 4. Generalize: Describe hw plants and animals each cntribute t the survival f the ther. (This type f cperative relatinship is called interdependence.) 5. Challenge: Simulate a 24-hur day (12 hurs f light, 12 hurs f dark). Hw many snails and plants d yu need t keep a stable envirnment? Explain any discveries yu make.

4 Activity C: Linking O 2 and CO 2 Get the Gizm ready: Click Reset. Clear all f the test tubes. Turn the light switch t n. Check Shw xygen and CO 2 values. Questin: Hw are the amunts f xygen and carbn dixide related t each ther? 1. Observe: Put tw Eldea sprigs int a test tube. Put the O 2/CO 2 prbe int the tube with the Eldea. Click Play. As the Gizm runs, Pause ( ) it a few times. A. Hw d the xygen (O 2) and carbn dixide (CO 2) levels change ver time? B. What is always true abut the ttal amunt f O 2 and CO 2 in the test tube? C. What happens when the CO 2 reaches zer? 2. Revise and repeat: Click Reset and run the experiment again, this time with the lights ff. A. Hw d the gas levels change? O 2 CO 2 B. What is the ttal f O 2 and CO 2? 3. Revise and repeat: Click Reset. Remve the plants. Repeat the experiment with tw snails. A. Hw d the gas levels change? O 2 CO 2 B. What is the ttal f O 2 and CO 2? C. Why d the gas levels stp changing in this case? 4. Challenge: The ttal f the O 2 and CO 2 in the test tubes always stayed the same. Why d yu think this is? (Hint: Mlecules f carbn dixide, CO 2, are made f carbn, C, bnded tgether with tw mlecules f xygen, O.)

5 Vcabulary: Plants and Snails Vcabulary Brmthyml blue (BTB) a chemical that changes clr t indicate if xygen r carbn dixide is present in water. When xygen is present, BTB turns frm green t blue. When carbn dixide is present, BTB turns frm green t yellw. Carbn dixide-xygen cycle the exchange f carbn dixide and xygen between plants and animals. During phtsynthesis, plants take in carbn dixide and water, prducing xygen and glucse. During respiratin, animals (and plants) take in xygen and glucse t prduce carbn dixide and water. Respiratin ccurs in plants and animals. Phtsynthesis nly ccurs in plants. Indicatr a chemical that can shw if anther substance is present, usually by changing clr. Interdependence a relatinship between living things in which bth make smething that the ther ne needs.