penny lab

Penny Lab Template

February 10, 2019

3:13 PM

  PENNY LAB

Purpose:

  To determine how many drops of water fit on one side of a penny.

Hypothesis: (Use an if-then-because statement for your hypothesis)

If the soap is added onto the penny, the strength of the surface tension will weaken because mixing the hydrogen and oxygen molecules with that of the soaps will cause the molecules to bond less with each other and merge with the soap.

Materials: (List all the materials used in the experiment)

2 glass beaker – one is 100ml and one is 50 ml

8 pennies

1 eye droppers

30ml of soap

100ml of water

Tweezers

Paper towels

Procedure:

Part A: Perform a CONTROL test for comparison with later results.

Step 1: Rinse a penny in tap water and dry completely.

Step 2: Place the penny on paper towel.

Step 3: Use an eye dropper to place drops of WATER on the penny (one at a time) until ANY amount of water runs over the edge of the penny.

Step 4: Record the number of drops for that trial in the table.

Repeat Steps 1 – 4 three more times before calculating your average.

Number of drops

TRIAL 1

Number of drops

TRIAL 2

Number of drops

TRIAL 3

Number of drops

TRIAL 4

AVERAGE Number of drops

 

 

 

27

 13  21  25  21

Part B: Perform tests with the TESTING LIQUID.

Step 1: Start with a “clean” penny. Rinse the penny in tap water and dry completely. Be sure to remove as much residue as possible – without using soap!

Step 2: Hold the penny with the tweezers provided, then dip it into the TESTING LIQUID. Allow extra liquid

to drip off the penny into the container before proceeding to the next step.

Step 3: Place penny on dry spot on a paper towel. Place drops of WATER on the penny (one at a time) until ANY amount of water runs over the edge of the penny.

Step 4: Record your observations and the number of drops for that trial in the table.

Repeat Steps 1 – 4 three more times before calculating the average.

TRIAL 1 TRIAL 2 TRIAL 3 TRIAL 4 AVERAGE
 2

 

 

 4  4 10  5

Observations:

Part One:  Labelled Diagram of observations:

 

 

 

 

 

 

 

 

Part Two:  Labelled Diagram of observations:

 

 

Description:

for the lab as you drop the water on to the penny it starts to shape a globe like clear shape. When the droplet starts to grow it goes over the rim of the penny.

 

 

 

 

 

 

Description:

When you cover the penny in soap it affects how the water sits of the penny so the surface tension is weaker then when there is soap.

 

 

 

 

 

 

 

 

 

 

 

 

 

Results:

Group # Average Number of water Drops on the Control Penny Average Number of Drops on the

Penny submersed in the soap solution

Group One

 

27 5
Group Two

 

22 5
Group Three

 

33 6
Group Four

 

20 8
Group Five

 

34 8

class average : 27                                         6

Conclusion:

This experiment investigated whether or not soap effected the surface tension on a penny. In order to study this problem we used 8 pennies, soap and water. On 4 pennies we used eyedroppers and counted how many drops of water the penny could hold until the surface tension broke. Then we tried again on another set of pennies the only difference was the next set of pennies were covered in soap.

Results showed that when you add soap to the equation it does effect the surface tension on the penny. My hypothesis was ‘If the soap is added onto the penny, the strength of the surface tension will weaken because mixing the hydrogen and oxygen molecules with that of the soaps will cause the molecules to bond less with each other and merge with the soap.’ and this hypothesis was supported because when we did the lab the average drop that the pennies could hold with soap was 5 drops and the penny with out soap had an average of 21 drops. So therefore when you cover a penny with soap it effects the entire lab and changes how the water sits on top of the penny. Thing to improve the lab and test the different theories for this project could be like changing what covers the pennies. Try different types of soap or oils.

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