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# Cell Size Lab (potato)

## Question:

What is the effect of cube size on the ability of the cell to interact with their external environments?

## Background:

(Summarize what you know about the size of cells, surface area and volume, and the interaction of cells with their external environments.)

## Hypothesis:

(Predict what will happen to the interaction of cells with their external environments when the size of the cubes are increased.)

## Materials:

Safety goggles | Potato | Metric ruler | Spoon or tongs, |

Iodine solution | Knife | Beaker, 100mL | Distilled water ~60 mL |

## Procedure:

- Safety goggles will be worn at all times.
- Each group will cut three potato cubes: a 0.5cm cube, a 1cm cube, and a 2cm cube. Cut as accurately as possible.
- Place the cubes in the bottom of the beaker such that the potato cubes are not touching the sides of the beaker or each other.
- Pour in distilled water until the potato cubes are just covered. Add ___ drops of iodine solution.
- Every ___ minutes swirl the iodine solution gently. After ___ minutes, use a spoon or tongs to remove the blocks and blot dry with a paper towel.
- Pour the iodine solution into the waster container the instructor showed you.
- Promptly cut each block in half and measure the depth to which the brown color has penetrated.
- Sketch each block's cross section.

## Data:

(Record all data on a data table. Include that data table and any calculations and graphs in this section)

Length of a cube side | Surface area (cm^{2}) |
Volume (cm^{3}) |
Penetration distance (cm) | Surface area / volume ratio |

0.5 | ||||

1 | ||||

2 |

## Analysis

- Make two x-y scatter plot graphs:
- side length vs. the surface area AND side length vs. the volume .
- the volume vs. the surface area.

- For each cube make a calculation of the percentage of penetration.
- % penetration = volume of color change / total volume
- Volume of color change = Total volume – Not brown volume

Length of a cube side (cm) Volume (cm ^{3})Penetration distance (cm) Length of not brown cube side (cm) Not brown volume (cm ^{3})% penetration 0.5 1 2 - Use a scatter plot to show S/V Ratio vs. percent of penetration.

## Conclusion:

(Write your conclusion in this section. Be sure to follow all guidelines for writing conclusions to experiments and include data and an explanation of how the data supports your conclusion)