Difference between revisions of "PhET/C2/pH-Scale/English-timed"

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|-  
 
|-  
 
|00:01
 
|00:01
−
| Welcome to this Spoken tutorial on '''pH scale''' using '''interactive PhET simulation'''.
+
| Welcome to this Spoken tutorial on '''pH scale''' using interactive '''PhET simulation'''.
  
 
|-
 
|-
Line 11: Line 11:
 
| In this tutorial we will learn-
 
| In this tutorial we will learn-
  
−
How to use '''interactive PhET simulation''', '''pH scale'''.
+
How to use interactive '''PhET simulation''', '''pH scale'''.
  
 
|-
 
|-
Line 32: Line 32:
 
|00:38
 
|00:38
 
| Using this '''simulation''' we will learn to-
 
| Using this '''simulation''' we will learn to-
−
Determine whether a given solution is an '''acid''' or a '''base'''.
+
1. Determine whether a given solution is an acid or a base.
  
 
|-
 
|-
 
|00:49
 
|00:49
−
|Arrange '''acids''' and '''bases''' according to their strength,
+
|2. Arrange acids and bases according to their strength,
−
Determine the '''concentration''' of '''hydroxide ion''',
+
3. Determine the concentration of hydroxide ion,
−
'''hydronium ion''' and '''water''' at a given '''pH'''.
+
hydronium ion and water at a given '''pH'''.
  
 
|-
 
|-
Line 44: Line 44:
 
| Using this '''simulation''' we will learn about,
 
| Using this '''simulation''' we will learn about,
  
−
'''pH''' of a solution.
+
4. '''pH''' of a solution.
  
−
Effect of dilution on '''pH''' of a solution.
+
5.Effect of dilution on '''pH''' of a solution.
  
−
'''Logarithmic''' and '''Linear''' scale.
+
6.'''Logarithmic''' and '''Linear''' scale.
  
 
|-
 
|-
 
|01:16
 
|01:16
−
| '''pH scale''' is a, numeric scale used to specify the '''acidity''' or '''basicity''' of an aqueous solution.
+
| '''pH scale''' is a, numeric scale used to specify the acidity or basicity of an aqueous solution.
  
 
|-
 
|-
 
|01:25
 
|01:25
−
| '''pH''' is a measure of '''hydrogen ion concentration''' in mol/L.
+
| '''pH''' is a measure of hydrogen ion concentration in '''mol/L'''.
  
 
|-
 
|-
 
|
 
|
−
| '''pH''' is negative '''logarithm''' to base 10 of '''hydrogen ion concentration'''.
+
| '''pH''' is negative logarithm to base 10 of hydrogen ion concentration.
 +
 
 
'''pH = - log[H]'''
 
'''pH = - log[H]'''
  
 
|-
 
|-
 
|01:37
 
|01:37
−
| For '''Acidic''' solutions, '''pH''' is less than 7(< 7).
+
| For acidic solutions, '''pH''' is less than 7(< 7).
  
 
|-
 
|-
 
|01:42
 
|01:42
−
|For '''Basic''' solutions, '''pH''' is greater than 7 (> 7).
+
|For basic solutions, '''pH''' is greater than 7 (> 7).
  
 
|-
 
|-
 
|01:47
 
|01:47
−
|For '''Neutral''' solutions, '''pH''' is equal to 7 (= 7).
+
|For neutral solutions, '''pH''' is equal to 7 (= 7).
  
 
|-
 
|-
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|-
 
|-
 
|02:08
 
|02:08
−
|Choose the option '''Open With Firefox Web Browser'''. The file opens in the '''Browser'''.
+
|Choose the option '''Open With Firefox Web Browser'''. The file opens in the browser.
  
 
|-
 
|-
 
|02:16
 
|02:16
−
| This is the ''' interface'''of '''pH scale simulation'''.
+
| This is the interface of '''pH scale simulation'''.
  
 
|-
 
|-
 
|02:20
 
|02:20
−
| The '''interface''' has three screens-
+
| The interface has three screens-
  
 
'''Macro'''  
 
'''Macro'''  
Line 123: Line 124:
 
|-
 
|-
 
|02:54
 
|02:54
−
| A '''Water pump''' on the right side of screen to add '''water'''.
+
| A water pump on the right side of screen to add water.
  
 
|-
 
|-
 
|02:59
 
|02:59
−
|A Graduated '''water container''' filled by default with '''Chicken Soup'''.
+
|A graduated water container filled by default with '''Chicken Soup'''.
  
 
|-
 
|-
 
|03:05
 
|03:05
−
|A '''pump''' to remove solution is attached at the bottom left of the '''container'''.
+
|A pump to remove solution is attached at the bottom left of the container.
  
 
|-
 
|-
 
|03:11
 
|03:11
−
| A '''Dropper''' to add liquid.
+
| A dropper to add liquid.
  
 
|-
 
|-
 
|03:14
 
|03:14
−
|A '''Drop down box''' to choose one of the liquids.By default '''Chicken Soup''' is selected.
+
|A drop down box to choose one of the liquids. By default '''Chicken Soup''' is selected.
  
 
|-
 
|-
 
|03:22
 
|03:22
−
| A '''Reset Button''' is provided at the right hand side bottom corner.
+
| A '''Reset''' button is provided at the right hand side bottom corner.
  
 
|-
 
|-
 
|03:28
 
|03:28
−
| Click on the '''drop down arrow'''.
+
| Click on the drop down arrow.
  
 
|-
 
|-
 
|03:31
 
|03:31
−
|Scroll to '''Battery Acid ''' and click on it. Notice that, the '''container''' is filled with '''Battery Acid''' up to 0.50 L (0.5litres).
+
|Scroll to '''Battery Acid ''' and click on it. Notice that, the container is filled with '''Battery Acid''' up to 0.50 L (0.5litres).
  
 
|-
 
|-
 
|03:42
 
|03:42
−
| Drag the green '''probe''' into the '''container''' and Observe the '''pH'''.  
+
| Drag the green '''probe''' into the container and observe the '''pH'''.  
  
 
|-
 
|-
 
|03:48
 
|03:48
−
|'''Meter''' shows the '''pH''' value as 1.0. As '''pH''' is less than 7(<7), '''Battery Acid''' is an '''acidic''' solution.
+
|'''Meter''' shows the '''pH''' value as 1.0. As '''pH''' is less than 7(<7), '''Battery Acid''' is an acidic solution.
  
 
|-
 
|-
 
|03:58
 
|03:58
−
| Now click on the '''water pump''' to add more '''water'''.
+
| Now click on the water pump to add more water.
  
 
|-
 
|-
 
|04:03
 
|04:03
−
|Increase the '''water''' level up to 1Litre. Observe the change in '''pH''' on addition of '''water'''.
+
|Increase the water level up to 1 Litre. Observe the change in '''pH''' on addition of water.
 
Now '''pH meter''' shows '''pH''' value as 1.30.
 
Now '''pH meter''' shows '''pH''' value as 1.30.
  
 
|-
 
|-
 
|04:16
 
|04:16
−
| Notice that '''pH''' of '''Battery Acid''' increases on addition of '''water'''. This is because '''hydrogen [H] ion concentration''' decreases with dilution.
+
| Notice that '''pH''' of '''Battery Acid''' increases on addition of water.  
 +
 
 +
This is because hydrogen [H] ion concentration decreases with dilution.
  
 
|-
 
|-
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|-
 
|-
 
|04:32
 
|04:32
−
| Click on '''drop down arrow'''.
+
| Click on drop down arrow.
  
 
|-
 
|-
 
|04:34
 
|04:34
−
|Scroll to '''Hand Soap''' and click on it. '''Container''' is filled with '''Hand Soap''' solution.
+
|Scroll to '''Hand Soap''' and click on it. Container is filled with '''Hand Soap''' solution.
  
 
|-
 
|-
 
|04:42
 
|04:42
−
| Here, '''pH meter''' shows the value of '''pH''' as 10.00. This indicates that '''Hand Soap''' is '''basic''' in nature.
+
| Here, '''pH meter''' shows the value of '''pH''' as 10.00. This indicates that '''Hand Soap''' is basic in nature.
  
 
|-
 
|-
 
|04:54
 
|04:54
−
| Click on '''water pump''' to add '''water''' to ''' Hand Soap''' solution.
+
| Click on water pump to add water to '''Hand Soap''' solution.
  
 
|-
 
|-
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|-
 
|-
 
|05:12
 
|05:12
−
|This is because '''hydroxide ion (OH) concentration''' decreases with dilution.
+
|This is because hydroxide ion (OH) concentration decreases with dilution.
  
 
|-
 
|-
 
|05:18
 
|05:18
−
| Click on the bottom '''pump''' to remove half litre of '''Hand Soap''' solution.
+
| Click on the bottom pump to remove half litre of '''Hand Soap''' solution.
  
 
|-
 
|-
 
|05:24
 
|05:24
−
|Click on the '''dropper''' and increase the level of '''Hand Soap''' solution to 0.6 L. Notice the change in '''pH'''.
+
|Click on the dropper and increase the level of '''Hand Soap''' solution to 0.6 L. Notice the change in '''pH'''.
  
 
|-
 
|-
 
|05:34
 
|05:34
−
|It increases as '''concentration''' of '''hydroxide ion (OH)''' increases.  
+
|It increases as concentration of hydroxide ion (OH) increases.  
  
 
|-
 
|-
 
|05:39
 
|05:39
−
| Now we will arrange the '''acids''' and '''bases''' according to their strengths.
+
| Now we will arrange the acids and bases according to their strengths.
  
 
|-
 
|-
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|-
 
|-
 
|05:50
 
|05:50
−
| Click on '''drop down arrow''' and select '''Blood'''. '''Container''' is filled with '''Blood''' up to 0.50 L.
+
| Click on drop down arrow and select '''Blood'''. Container is filled with '''Blood''' up to 0.50 L.
  
 
|-
 
|-
 
|05:59
 
|05:59
−
| '''Meter''' shows the '''pH''' value as 7.40. As '''pH''' is greater than 7( >7), '''Blood''' is a '''basic''' solution.
+
| '''Meter''' shows the '''pH''' value as 7.40. As '''pH''' is greater than 7( >7), '''Blood''' is a basic solution.
  
 
|-
 
|-
 
|06:09
 
|06:09
−
|Again click on '''drop down arrow''' and select '''Orange Juice'''.
+
|Again click on drop down arrow and select '''Orange Juice'''.
  
 
|-
 
|-
 
|06:14
 
|06:14
−
|'''Meter''' shows '''pH''' value as 3.50 for 0.50 L. It is clear that '''Orange Juice''' is an '''acidic''' solution.
+
|'''Meter''' shows '''pH''' value as 3.50 for 0.50 L. It is clear that '''Orange Juice''' is an acidic solution.
  
 
|-
 
|-
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| According to the above '''pH''' values the order is as follows.  
 
| According to the above '''pH''' values the order is as follows.  
  
−
'''Hand soap > Blood > Orange Juice> Battery Acid'''.
+
'''Hand soap''' > '''Blood''' > '''Orange Juice''' > '''Battery Acid'''.
  
 
|-
 
|-
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|-
 
|-
 
|06:48
 
|06:48
−
|Now, we will move on to Micro screen. Click on Micro screen at the bottom of the interface.  
+
|Now, we will move on to '''Micro''' screen. Click on '''Micro''' screen at the bottom of the interface.  
  
 
|-
 
|-
Line 288: Line 291:
 
|-
 
|-
 
|07:38
 
|07:38
−
| Click on the '''drop down arrow''' and select '''Soda Pop'''.'''Container''' is filled with '''Soda Pop'''.
+
| Click on the drop down arrow and select '''Soda Pop'''.
 +
 
 +
Container is filled with '''Soda Pop'''.
  
 
|-
 
|-
Line 296: Line 301:
 
|-
 
|-
 
|07:54
 
|07:54
−
| As '''Soda Pop''' is '''acidic''', '''Concentration''' of '''hydronium ion''' is high and '''hydroxide ion''' is low.
+
| As '''Soda Pop''' is acidic, concentration of hydronium ionis high and hydroxide ion is low.
  
 
|-
 
|-
Line 304: Line 309:
 
|-
 
|-
 
|08:05
 
|08:05
−
|We will see the number of moles of '''hydronium ion''', '''hydroxide ion''' and '''water'''.
+
|We will see the number of moles of hydronium ion, hydroxide ion and water.
  
 
|-
 
|-
Line 320: Line 325:
 
|-
 
|-
 
|08:34
 
|08:34
−
| Click on''' Hydronium ion '''to''' hydroxide ion ratio (H<sub>3</sub>0<sup>+</sup>/OH<sup>-</sup>) ''' check box.
+
| Click on Hydronium ion to hydroxide ion ratio '''(H<sub>3</sub>0<sup>+</sup>/OH<sup>-</sup>)''' check box.
  
 
|-
 
|-
 
|08:39
 
|08:39
−
|A large number of red dots are seen in the '''container'''. These are '''hydronium ions'''.
+
|A large number of red dots are seen in the container. These are hydronium ions.
  
 
|-
 
|-
 
|08:46
 
|08:46
−
|A few blue dots that are seen are '''hydroxide ions''' (OH).  
+
|A few blue dots that are seen are hydroxide ions'''(</sup>/OH<sup>-</sup>)'''.  
  
 
|-
 
|-
Line 336: Line 341:
 
|-
 
|-
 
|08:57
 
|08:57
−
|Count of '''hydronium ions''', '''hydroxide ions''' and '''water''' molecules in '''Soda Pop''' is seen.
+
|Count of hydronium ions, hydroxide ions and water molecules in '''Soda Pop''' is seen.
  
 
|-
 
|-
Line 344: Line 349:
 
|-
 
|-
 
|09:10
 
|09:10
−
|Click on '''water pump''', fill the '''container''' up to 1 L. Observe the change in '''Molecule Count'''.
+
|Click on water pump, fill the container up to 1 L. Observe the change in '''Molecule Count'''.
 
Note the increase in '''pH''' value. '''pH''' becomes 2.80.
 
Note the increase in '''pH''' value. '''pH''' becomes 2.80.
  
 
|-
 
|-
 
|09:25
 
|09:25
−
| As an '''assignment''', Measure the '''pH''' of '''Blood''' sample.
+
| As an assignment, measure the '''pH''' of '''Blood''' sample.
  
 
|-
 
|-
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|-
 
|-
 
|09:37
 
|09:37
−
| Now, we will move on to '''My Solution''' screen. Click on '''My Solution''' screen at the bottom of the '''interface'''.
+
| Now, we will move on to '''My Solution''' screen. Click on '''My Solution''' screen at the bottom of the interface.
  
 
|-
 
|-
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|-
 
|-
 
|09:57
 
|09:57
−
|A Graduated '''container''' on the right hand side of screen. A '''pH meter''' to adjust '''pH''' directly.
+
|A graduated container on the right hand side of screen. A '''pH meter''' to adjust '''pH''' directly.
  
 
|-
 
|-
 
|10:05
 
|10:05
−
| This screen allows direct manipulation of '''pH''' or ion '''concentration'''.
+
| This screen allows direct manipulation of '''pH''' or ion concentration.
  
 
|-
 
|-
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|-
 
|-
 
|10:28
 
|10:28
−
| Let us move the '''hydronium ion (H<sub>3</sub>0<sup>+</sup>)''' slider upwards.
+
| Let us move the hydronium ion '''(H<sub>3</sub>0<sup>+</sup>)''' slider upwards.
  
 
|-
 
|-
 
|10:32
 
|10:32
−
|Notice that, simultaneously '''Hydroxide ion(OH<sup>-</sup>)''' slider also moves downwards.
+
|Notice that, simultaneously Hydroxide ion '''(OH<sup>-</sup>)''' slider also moves downwards.
  
 
|-
 
|-
 
|10:38
 
|10:38
−
| Let's make a solution of '''pH''' 4.0 by clicking the black arrow downwards. This is an '''acidic''' solution.
+
| Let's make a solution of '''pH''' 4.0 by clicking the black arrow downwards. This is an acidic solution.
  
 
|-
 
|-
 
|10:48
 
|10:48
−
| Now, Click on '''Hydronium ion''' to '''hydroxide ion (H<sub>3</sub>0<sup>+</sup>/OH<sup>-</sup> )ratio''' and '''Molecule count''' check boxes.
+
| Now, click on Hydronium ion to hydroxide ion '''(H<sub>3</sub>0<sup>+</sup>/OH<sup>-</sup>)''' ratio and '''Molecule count''' check boxes.
  
 
|-
 
|-
 
|10:55
 
|10:55
−
|Notice that '''Molecule count''' for '''hydronium ion''' (H<sub>3</sub>0<sup>+</sup>)<sup> </sup>is 3.01 x 10<sup>19</sup>.
+
|Notice that '''Molecule count''' for hydronium ion '''(H<sub>3</sub>0<sup>+</sup>)<sup> </sup>is 3.01 x 10<sup>19</sup>'''.
  
 
|-
 
|-
 
|11:01
 
|11:01
−
| As an '''assignment''',
+
| As an assignment,
  
 
Make solutions of '''pH''' 7.0 and 9.0.
 
Make solutions of '''pH''' 7.0 and 9.0.
Line 415: Line 420:
 
| Let us summarize.
 
| Let us summarize.
  
−
In this tutorial we have learnt about, '''interactive PhET simulation, pH scale'''.
+
In this tutorial we have learnt about, interactive '''PhET simulation, pH scale'''.
  
 
|-
 
|-
Line 421: Line 426:
 
| Using this simulation we have learnt to-
 
| Using this simulation we have learnt to-
  
−
Determine whether a given solution is an '''acid''' or a '''base'''.
+
1.Determine whether a given solution is an acid or a base.
  
 
|-
 
|-
 
|11:31
 
|11:31
−
|Arrange '''acids''' and '''bases''' according to their strength.  
+
|2. Arrange acids and bases according to their strength.  
−
 
+
 
|-
 
|-
 
|11:36
 
|11:36
−
|Determine the concentration of '''hydronium ion''', '''hydroxide ion''' and '''water''' at a given '''pH'''.
+
|3. Determine the concentration of hydronium ion, hydroxide ion and water at a given '''pH'''.
  
 
|-
 
|-
 
|11:43
 
|11:43
−
| '''pH''' of a solution.
+
|4. '''pH''' of a solution.
  
−
Effect of dilution on '''pH''' of solution.
+
5. Effect of dilution on '''pH''' of solution.
  
−
'''Logarithmic''' and '''Linear scale'''.
+
6. '''Logarithmic''' and '''Linear scale'''.
  
 
|-
 
|-
 
|11:53
 
|11:53
−
| The '''video''' at the following link summarizes the Spoken Tutorial project. Please download and watch it.
+
| The video at the following link summarizes the Spoken Tutorial project. Please download and watch it.
  
 
|-
 
|-
 
|12:02
 
|12:02
−
| The '''Spoken Tutorial Project''' team:
+
| The Spoken Tutorial Project team:
  
 
Conducts workshops using spoken tutorials and gives certificates on passing online tests.
 
Conducts workshops using spoken tutorials and gives certificates on passing online tests.
Line 465: Line 469:
 
|12:41
 
|12:41
 
| This is '''Meenal Ghoderao''' from '''IIT Bombay'''. Thank you for joining.
 
| This is '''Meenal Ghoderao''' from '''IIT Bombay'''. Thank you for joining.
−
 
+
|-
 
|}
 
|}

Revision as of 17:26, 7 August 2018

Time Narration
00:01 Welcome to this Spoken tutorial on pH scale using interactive PhET simulation.
00:08 In this tutorial we will learn-

How to use interactive PhET simulation, pH scale.

00:15 To follow this tutorial,

Learners should be familiar with topics in high school science.

00:22 Here I am using-

Ubuntu Linux OS version 14.04

Java version 1.7.0

Firefox Web Browser version 53.02.2.

00:38 Using this simulation we will learn to-

1. Determine whether a given solution is an acid or a base.

00:49 2. Arrange acids and bases according to their strength,

3. Determine the concentration of hydroxide ion, hydronium ion and water at a given pH.

01:01 Using this simulation we will learn about,

4. pH of a solution.

5.Effect of dilution on pH of a solution.

6.Logarithmic and Linear scale.

01:16 pH scale is a, numeric scale used to specify the acidity or basicity of an aqueous solution.
01:25 pH is a measure of hydrogen ion concentration in mol/L.
pH is negative logarithm to base 10 of hydrogen ion concentration.

pH = - log[H]

01:37 For acidic solutions, pH is less than 7(< 7).
01:42 For basic solutions, pH is greater than 7 (> 7).
01:47 For neutral solutions, pH is equal to 7 (= 7).
01:52 Use the given link to download the simulation.

http://phet.colorado.edu

01:57 I have already downloaded the pH Scale PhET, to my Downloads folder.
02:02 To open the simulation, right click on ph-scale html file.
02:08 Choose the option Open With Firefox Web Browser. The file opens in the browser.
02:16 This is the interface of pH scale simulation.
02:20 The interface has three screens-

Macro

Micro

My solution

02:27 Let us begin our simulation with Macro screen. Click on Macro screen to open it.
02:36 This screen has-

A pH scale on the left, to display pH range from 0 to 14.

02:44 A green probe attached to pH scale to measure pH and A pH meter to show pH of the liquids.
02:54 A water pump on the right side of screen to add water.
02:59 A graduated water container filled by default with Chicken Soup.
03:05 A pump to remove solution is attached at the bottom left of the container.
03:11 A dropper to add liquid.
03:14 A drop down box to choose one of the liquids. By default Chicken Soup is selected.
03:22 A Reset button is provided at the right hand side bottom corner.
03:28 Click on the drop down arrow.
03:31 Scroll to Battery Acid and click on it. Notice that, the container is filled with Battery Acid up to 0.50 L (0.5litres).
03:42 Drag the green probe into the container and observe the pH.
03:48 Meter shows the pH value as 1.0. As pH is less than 7(<7), Battery Acid is an acidic solution.
03:58 Now click on the water pump to add more water.
04:03 Increase the water level up to 1 Litre. Observe the change in pH on addition of water.

Now pH meter shows pH value as 1.30.

04:16 Notice that pH of Battery Acid increases on addition of water.

This is because hydrogen [H] ion concentration decreases with dilution.

04:28 Now we will select another solution.
04:32 Click on drop down arrow.
04:34 Scroll to Hand Soap and click on it. Container is filled with Hand Soap solution.
04:42 Here, pH meter shows the value of pH as 10.00. This indicates that Hand Soap is basic in nature.
04:54 Click on water pump to add water to Hand Soap solution.
04:59 For 1 L, Hand Soap solution shows a pH value of 9.70.
05:06 We can see that pH of Hand Soap solution decreases on dilution.
05:12 This is because hydroxide ion (OH) concentration decreases with dilution.
05:18 Click on the bottom pump to remove half litre of Hand Soap solution.
05:24 Click on the dropper and increase the level of Hand Soap solution to 0.6 L. Notice the change in pH.
05:34 It increases as concentration of hydroxide ion (OH) increases.
05:39 Now we will arrange the acids and bases according to their strengths.
05:45 For that we will check the pH of different liquids.
05:50 Click on drop down arrow and select Blood. Container is filled with Blood up to 0.50 L.
05:59 Meter shows the pH value as 7.40. As pH is greater than 7( >7), Blood is a basic solution.
06:09 Again click on drop down arrow and select Orange Juice.
06:14 Meter shows pH value as 3.50 for 0.50 L. It is clear that Orange Juice is an acidic solution.
06:26 According to the above pH values the order is as follows.

Hand soap > Blood > Orange Juice > Battery Acid.

06:38 As an assignment,

Check the pH of each liquid.

And arrange the liquids according to the pH range.

06:48 Now, we will move on to Micro screen. Click on Micro screen at the bottom of the interface.
06:57 This screen has the following tools-

A pH scale on the left hand side of screen.

07:04 A switch on the top of pH scale to select between Concentration and Quantity.

A red button with a minus(-) to hide pH scale.

07:16 A switch at the bottom to select between Logarithmic and Linear scale.
07:22 Check boxes to select-

Hydronium ion to hydroxide ion ratio (H30+/OH- ) and Molecule count.

07:30 In the pH meter, a red button with a minus(-) to hide pH reader and value.
07:38 Click on the drop down arrow and select Soda Pop.

Container is filled with Soda Pop.

07:46 pH meter shows pH value as 2.50. It means, Soda Pop is an acidic solution.
07:54 As Soda Pop is acidic, concentration of hydronium ionis high and hydroxide ion is low.
08:02 Then click on Quantity(mol),
08:05 We will see the number of moles of hydronium ion, hydroxide ion and water.
08:12 Let us change Logarithmic scale to Linear. To do so click on Linear .
08:20 The pH scale changes to Linear mode. We also see that pH values become Linear.
08:28 But we will not use Linear scale as pH is in Logarithmic scale.
08:34 Click on Hydronium ion to hydroxide ion ratio (H30+/OH-) check box.
08:39 A large number of red dots are seen in the container. These are hydronium ions.
08:46 A few blue dots that are seen are hydroxide ions(</sup>/OH-).
08:51 To see count of molecules in Soda Pop, click on Molecule count check box.
08:57 Count of hydronium ions, hydroxide ions and water molecules in Soda Pop is seen.
09:05 Let us see how dilution affects the number of molecules.
09:10 Click on water pump, fill the container up to 1 L. Observe the change in Molecule Count.

Note the increase in pH value. pH becomes 2.80.

09:25 As an assignment, measure the pH of Blood sample.
09:30 Observe the change in Molecule Count and H30+/OH- ratio after dilution.
09:37 Now, we will move on to My Solution screen. Click on My Solution screen at the bottom of the interface.
09:46 My Solution screen has the same tools as that of Macro and Micro screens.
09:53 This screen also has some additional tools.
09:57 A graduated container on the right hand side of screen. A pH meter to adjust pH directly.
10:05 This screen allows direct manipulation of pH or ion concentration.
10:11 In this screen, we can make a solution of our choice in two ways-

By moving the H30+or OH- slider on pH scale.

By clicking black arrow upwards or downwards.

10:28 Let us move the hydronium ion (H30+) slider upwards.
10:32 Notice that, simultaneously Hydroxide ion (OH-) slider also moves downwards.
10:38 Let's make a solution of pH 4.0 by clicking the black arrow downwards. This is an acidic solution.
10:48 Now, click on Hydronium ion to hydroxide ion (H30+/OH-) ratio and Molecule count check boxes.
10:55 Notice that Molecule count for hydronium ion (H30+) is 3.01 x 1019.
11:01 As an assignment,

Make solutions of pH 7.0 and 9.0.

Observe and compare the change in molecules.

11:13 Let us summarize.

In this tutorial we have learnt about, interactive PhET simulation, pH scale.

11:22 Using this simulation we have learnt to-

1.Determine whether a given solution is an acid or a base.

11:31 2. Arrange acids and bases according to their strength.
11:36 3. Determine the concentration of hydronium ion, hydroxide ion and water at a given pH.
11:43 4. pH of a solution.

5. Effect of dilution on pH of solution.

6. Logarithmic and Linear scale.

11:53 The video at the following link summarizes the Spoken Tutorial project. Please download and watch it.
12:02 The Spoken Tutorial Project team:

Conducts workshops using spoken tutorials and gives certificates on passing online tests. For more details, please write to us.

12:15 Please post your timed queries in this forum.
12:21 This project is partially funded by Pandit Madan Mohan Malaviya National Mission on Teachers and Teaching.
12:29 Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India. More information on this mission is available at this link.
12:41 This is Meenal Ghoderao from IIT Bombay. Thank you for joining.

Contributors and Content Editors

Madhurig, PoojaMoolya, Sandhya.np14

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