Water Lab Report Hl Bio Ib

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Water lab

Research Question:
How many drops of water can fit on a coin?
(Water properties involved are cohesion and surface tension. Cohesion plays a consequential role in the transport of water within plants specifically within the phloem. Surface tension also dictates an important role within the transpirational pull of the xylem.)

Variables:
Variables| Type of Variable| How it was manipulated|
Independent| Water drops, different types of water| Determining how many drops of the different types of water would fit onto the coin. | Dependent| Water drops| The amount of water drops that would fit on the penny was being recorded.| Controlled| Coin| The same coin was used throughout the experiment. |

Apparatus:
1) Coin
2) Eye dropper/ pipette
3) Styrofoam cup
4) Paper towels
5) Thermometer
6) Room temperature tap water
7) Boiling temperature tap water
8) Freezing temperature tap water
9) Distilled water
10) Salt water

Method:
Step 1: Rinse the coin in tap water and dry completely.
Step 2: Place the coin on a paper towel.
Step 3: Fill a pipette with the first form of water (room temperature) preferably and practice carefully dropping one drop at a time into the Styrofoam cup. Step 4: Hold the pipette vertically above the coin by around one centimeter. Step 5: Make sure to keep your hand steady, any movement will affect the data. Step 6: Place as any drops onto the coin as possible until the water spills over. Step 7: Repeat four more times.

Step 8: Record data and find the average number of drops that fit onto the coin. Step 9: Repeat process but with another form of water.

Gathered Data:
Room temperature tap water
Test 1| Test 2| Test 3| Test 4| Test 5| Average|
18.0 drops| 15.0 drops| 21.0 drops| 16.0 drops| 22.0 drops| 18.4 drops|

Boiling temperature tap water
Test 1| Test 2| Test 3| Test 4| Test 5| Average|
12.0 drops| 11.0 drops| 15.0 drops| 14.0 drops| 18.0 drops| 14.0 drops|

Freezing temperature tap water
Test 1| Test 2| Test 3| Test 4| Test 5| Average|
21.0 drops| 24.0 drops| 27.0 drops| 22.0 drops| 31.0 drops| 25.0 drops|

Distilled water
Test 1| Test 2| Test 3| Test 4| Test 5| Average|
11.0 drops| 17.0 drops| 16.0 drops| 21.0 drops| 20.0 drops| 17.0 drops|

Salt water
Test 1| Test 2| Test 3| Test 4| Test 5| Average|
14.0 drops| 17.0 drops| 12.0 drops| 15.0 drops| 18.0 drops| 15.2 drops|

Processed data:

Standard deviation of each water type

Calculations:

Step 1: find the mean (average)
For ‘Room temperature tap water’ we added 18, 15, 21, 16 & 22, which resulted in 92. Now we divide 92 by the actual number of numbers, which in this case are 5. Therefore 92/5 = 18.4

Step 2: gather the deviations
During this step the mean we found in the previous step will be subtracted from each of the original numbers. 18 – 18.4 = -0.4, 15 – 18.4 = -3.4, 21 – 18.4 = 3.4, 16 – 18.4 = -2.4, 22 – 18.4 = 4.6.

Step 3: square the values found in step 2
Now we must square the values that we had discovered in the second step. -0.4 2 = 0.16, -3.4 2 = 11.56, 3.4 2= 11.56, -2.4 2= 5.76, 4.6 2 = 21.6

Step 4: Add all the squared values
0.16 + 11.56 + 11.56 + 5.76 + 21.6 = 50.64

Step 5: Divide by total number of integers minus 1
50.64/4 = 12.7

Step 6: Square root of the above result is standard deviation 12.7 = 3.56

Water type| Standard deviation|
Room temperature| 3.56 cm3|
Boiling temperature| 2.73 cm3|
Freezing temperature| 4.06 cm3|
Distilled water| 3.94 cm3|
Salt water| 2.39 cm3|

Graph:

Conclusion:
The major mechanism for long-distance water transport is described by the cohesion-tension theory, whereby the driving force of transport is transpiration, that is, the evaporation of water from the leaf surfaces. Water molecules cohere (stick together), and are pulled up the plant by the tension, or pulling force, exerted by...
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