1. 1.Turn in your Bell Work page – make sure your name is on it! 2.Open your journal to page 11 and set it up like the next slide. 3.DO NOT TOUCH ANY MATERIALS UNTIL I TELL YOU TO!!!!!!

2. Cell Size Lab 11 9-8-15 EQ: Why are cells small? QuestionsSmall CubeMedium CubeLarge Cube (Level 1) DESCRIBE __________________ __________________ __________________ (Level 2) EXPLAIN __________________ __________________ __________________ (Level 3) WHY __________________ __________________ _________________? Prediction: Hypothesis: Observation: Diagram: Prediction: Hypothesis: Observation: Diagram: Prediction: Hypothesis: Observation: Diagram: CONCLUSION:

3. Lab CHAMPs C : Talk ONLY to your group unless you are asking for help. All conversations ON TOPIC! H : Ask your neighbors and group first, then ask me. A : DO NOT TOUCH any materials until asked; complete all activities and questions. Appropriate safety gear must be worn! M : Stay with your group. One person moves to gather materials or ask for help. P : Head up, complete all tasks, and follow all directions as given. All group members actively participate.

4. Part 1 Procedure 1.You have 3 cm, 2 cm, and 1 cm agar cubes at your table. 2.When you put agar cubes into a sodium hydroxide (NaOH) solution, the solution will enter the cube. a)With your group, PREDICT what you think will happen in the three different sized blocks (hint: how far into the cube will the solution go??). 3.Turn your predictions into HYPOTHESES (ex: If I put in a small cube in NaOH, then the solution will ___________.). 4.Using your spoon, carefully place all three cubes in the NaOH solution. a)Use caution with sodium hydroxide - it is caustic. It will burn your skin or clothes. WEAR GOGGLES AT ALL TIMES!!!! 5.Allow the cubes to soak while you complete the next tasks.

5. While we wait, turn to page 12 in your journal. Title: Lab Analysis Copy the Data Table and Analysis Questions onto page 12.

6. Data Table Length / width / height of cube (cm) Surface area (cm 2 ) (length x width x 6) Volume (cm 3 ) (length x width x height) Surface Area: Volume ratio (# : #) 1 2 3 1.Which cube has the greatest… a)surface area? b)volume? c)surface area : volume ratio? 2.As the cubes get larger, what happens to the… a)surface area? b)volume? c)surface area : volume ratio? 3 (large) 24 cm 2 54 cm 2 1 cm 3 8 cm 3 27 cm 3 6 : 1 3 : 1 2 : 1 3 (large) 6 cm 2 1 (small) Gets larger Gets smaller

7. Analysis Questions 1.What do you notice about the agar cubes as they increase in size? (hint: look at your data table AND your observations!) 2.What happens to a cell’s ability to feed itself and get rid of wastes as it grows? 3.If the sodium hydroxide were food and the cubes were cells, which cell is being fed most efficiently? (Explain your answer) 4.Explain why cells are so small.

8. Part 2 Procedure 4.Without pouring the cubes out of your beaker, pour the NaOH solution down the sink and gently rinse the cubes. WEAR GLOVES AND GOGGLES UNTIL YOU’RE DONE. 5.At your table, use your spoon to remove the cubes from the beaker and lay them on your paper towel. 6.Cut the cubes in half and measure the depth of the colored area in cm. 7.Fill in your OBSERVATIONS, DIAGRAM, AND CONCLUSION spaces on the lab page. 8.Clean-up: ONE person take the paper towel and cubes to the trash. Leave your spoon and knife on the table.