Escience Lab 5

Experiment 1:

Table 1: pH values of common household substances

Substance: pH Guess: pH Paper

Vinegar 2 3

Sodium bicarbonate solution 10 8

Ammonia 8 12

Baking Soda 7 8

Water 7 7

Toothpaste 8 9

Questions:

1. Compare and contrast acids and bases in terms of their H+ ion and OH- ion concentrations.

Acids have a higher concentration of H+ ions and bases have a higher concentration of OH- ions.

2. Name two acids and two bases you often use.

Vinegar and lemons are two acids. Two bases are toothpaste and baking soda.

Experiment 2:

Table 2: Results from Surface Area to Volume Experiment

Cube Dimensions Surface Area(cm2) Volume(cm3) Surface Area: Volume Distance of Diffusion

1x1x1 6 1 6 6

2x2x2 24 8 3 4

1x1x6 36 6 6 2

Questions

1. How did the surface area affect the diffusion of the cube? What about the volume? What about the surface area to volume ratio? Which of these had the greatest effect on the diffusion of the cube?

The bigger the surface area, the diffusion is not enough. The volume is the same thing; the diffusion is not enough for the cell. The surface area to volume ratio doesn’t affect it. The surface area has the greatest effect on the diffusion rate.

2. How does this experiment demonstrate the need for larger cells to divide?

The larger the cells don’t diffuse as fast as the smaller cells.

3. For the three cubes shown below, determine their surface area, volume and surface area to volume ratio. Then, circle the one you believe would be the most efficient and write a summary stating why.

1.5 cm x 1.5 cm x 1.5 cm: SA: 11.4 V: 3.8 SA:V: 3

.5 cm x .5 cm x 6 cm: SA: 2.25 V:1.5 SA:V: 1.5

3 cm x 2 cm x 2 cm: SA: 144 V: 12 SA:V: 12

I think that the 1.5 x 1.5 x 1.5 cube will be the most efficient because it will be easier to diffuse when they are the same size.