Activity 8

Activity 8: Exploration of Chemistry
For activity 8, students have a choice to explore other topics of chemistry presented in the PhET simulations.
Tasks to be completed:
1. Choose any Teaching Idea from any of the Chemistry Simulations (http://phet.colorado.edu/en/simulations/category/chemistry ) and post your results/data and/or answers on your blog.

I chose to do the Balloons and Stacic Electricy activity written by the PhET Middle School Team

Static

Learning Objectives: 

·        Students will be able to determine the variables that affect how positive and negative objects interact.

·        Students will be able to predict how positive and negative objects will interact.

1. You and the class just made some observations with balloons – sticking and repelling.

Discuss with your partner your ideas about why the balloons would stick to things (like hair) after rubbing on your head? And repel from each other?

Use words and pictures to describe your ideas about what might be going on.

___The balloons will stick to hair because the energies are different but with two balloons they have the same molecules so they are repelled to each other like two batteries repelled to the opposite ends       ______________________________________

2. Let’s look at the Balloons and Static Electricity simulation.

a.      Explore the simulation.
How can you make the balloon stick to the sweater?
______I get the balloon to stick to the sweater by picking up all the negative electrons so they are attracted to the positive ones. ______
What makes it stick weakly versus strongly?

__It sticks less strong when the negative electrons are not sticking on the ballon and there is an equal mix of positive and negative. ________________________________________________________________________________________________________________________________________________________

b.      How do the plus or minus symbols help you decide whether something attracts or repels?

__it will attract if there is negative symbols on the balloon and positive symbols on the sweater because they are attracted to opposites. ________________________________________________________________________________________________________________________________________________________

c.       Talk about how your observations support, change or add to your ideas from Question 1 and about what affects whether things attract or repel. Then revise your ideas from Question 1.

They support my observation because things will attract to the opposite energy. They will repel from the same energy.

3.  With you partner, test your ideas about attraction and repulsion using the Electric Field Hockey simulation in the Practice mode.

      Play with the sim and talk with your partner about ideas that help you SCORE!

      Now, develop strategies for the following challenges:

Make a GOAL where puck takes the SHORTEST amount of time to get to the goal	Make a GOAL where puck takes the LONGEST amount of time to get to the goal
Draw your strategy for placing positives or negatives in the picture below.  What rules are you using to determine which direction the puck moves? ____I put negatives close to it and then in the goal in order to score quickly.___________________________ _______________________________ _______________________________ _______________________________ What rules are you using to determine how fast the puck moves? __I am using the rule of opposites._____________________________ _______________________________ _______________________________ _______________________________ _______________________________	Draw your strategy for placing positive or negative pucks in the picture below What rules are you using to determine which direction the puck moves? ______I put both positive and negative charges in its way so it took longer for it to get there._________________________ _______________________________ What rules are you using to determine how fast the puck moves? ____I used my knowledge of how opposites are attracted and the same ones are pushed away.___________________________ _______________________________ _______________________________ _______________________________ _______________________________

4.  Draw where you might put pucks to get a goal with the fewest pucks.

Explain why this works:
__Id put them negative pucks every few inches away to help guide the puck to the goal. It will be attracted to the negative pucks and follow them to the goal.________________

5. Reflect on your ideas from Questions 1&2 and your data from Questions 3&4. How do your observations support, change or add to your ideas about…

…whether two objects will attract and repel?

I have learned more about how objects attract each other with opposite energy and they repel with the same energy.

…how strongly they attract or repel?

            They will attract strongly based on the amount of energy given off. If there is a high negative energy and a high positive energy they will attract strongly but if there is two high positive energys they will repel strongly.

Revise your explanation from Question 1.

2. Work with any of the Chemistry Simulations to create your own Teaching Idea. The criteria for this is as follows:
a. must identify and meet three (3) science education standards
b. must be original work
c. must be scientifically accurate and appropriate for the directed grade level.
d. must meet two (2) literacy standards.
Think of this second activity as something that a K-8 teacher could use their curriculum. The activity is also designed to meet science and literacy standards at the same time.


                                               "Build Your Own Atom"
To be used with the "Build an Atom" simulation. This activity is created for a middle school level and the standards are for up to eighth grade.

This Activity will meet the following standards:

Science:
A.8.1 Develop their understanding of the science themes by using the themes to frame questions about science-related issues and problems

B.8.3 Explain how the general rules of science apply to the development and use of evidence in science investigations, model-making, and applications

C.8.1 Identify* questions they can investigate* using resources and equipment they have available

C.8.3 Design and safely conduct investigations* that provide reliable quantitative or qualitative data, as appropriate, to answer their questions



Literacy Standards:


Determine the meaning of words and phrases 
as they are used in a text, including vocabulary 
specific to domains related to history/social 
studies.

. Follow precisely a multistep procedure when 

carrying out experiments, taking measurements, 

or performing technical tasks.

Through this activity the student will be able to:

• Create an Atom with the correct structure
• Understand the difference between a stable and unstable atom
• Be able to answer their own questions by creating an experiment to prove it

To start this activity please open the Build an Atom activity on Phet.

1. First create a stable Neon atom. Note how many Protons, Neutrons and Electrons it has.

Protons:

Neutrons:

Electrons

Now create an unstable Neon atom. Note how many Protons, Neutrons, and Electrons it has.

Protons:

Neutrons:

Electrons:

What do you see as the difference between the stable atom and the unstable atom? 

How would you create an Isotope of Neon? How many Protons, Neutrons,and Electrons does it have? What is its mass? Does this change? 

Protons:

Neutrons:

Electrons:

Mass:

2. Create two positive ions and two negative ions. Give the Element name, mass number, and the amount of Protons, Neutrons, and Electrons for each one. 



3. While using the simulation come up with a question that could be answered using it as a tool. Make sure your question is original and can be answered using evidence from the simulation. 

        b. How would you answer your question? Create a list of steps to find an answer for your question. Keep in mind your steps should be able to be done by someone who has no knowledge of this subject but would like to find the answer to your scientific question. 


4. Is it possible to change an elements mass while keeping it the same element? What happens if you add neutrons to an element? What happens if you add extra protons to an element? Use a specific element as an example. 

5. How do you make an atom "neutral"? What do you think the word neutral means in this context? 

6. I have a helium atom with 2 protons, 5 neutrons, and 2 electrons. Is this a neutral atom? Why or why not do you think this is?  What does this say about what makes an atom neutral?

Activity 7

1. Review the Content Slides Acids and Bases on the D2L site.

2. Complete the Teaching Idea “Concept Questions for Chemistry using PhET”  posted by Trish Loeblein on the pH Scale simulation at PHET (http://phet.colorado.edu/en/simulation/ph-scale). On your blog post the answers with your scientific explanations from the “Clicker Questions pH Scale” posted by Trish.

1. False. The color of the solution does not signify if it is a acid or base. It is the color of the Ph scale that signifiys if it is an acid, base, or neutral.

2. D More than one. It would be both B and C because both of their PH's are over 7.0 so they could both be considered basic.

3. C. There is more H30 in the solution and very little OH. OH is more basic and H3O is more acidic.

4. B. There is much more OH than H30. The OH is Basic so it overcomes the H30 since there is more of it.

5. D. I believe there would be more than one. Both A and B would be acidic because there is more H30 than there is OH in these.

6. A. Increase the PH. The water lessens the acid which makes the PH go up.

7. B. More water will decrease the PH because it decreases the basicity

8. A. The lower the PH the more acidic it is. The higher the PH the more basic it is.

9. E. The more OH a substance has the more basic it is, The more H3O a substance has the more acidic it is. When the OH and H3O are equal they are neutral.

10. A. it had to shift left because the pH went up from 7.

3. Complete the Teaching Idea “Intro to Strong and Weak Acids and Bases” posted by Chris Bires on the Acid-Base Solutions simulation (http://phet.colorado.edu/en/simulation/acid-base-solutions) and post on your blog your data and answers to the questions posed.

Name:____________________

Introduction to Strong and Weak Acids and Bases PhET Lab (rvsd 5/2011)

        How does the strength of an acid or base affect conductivity?pH?

Introduction:

When you test your pool’s pH, what are you those little vials or paper strips telling you?  When you hear an acid called “strong” or “weak”, what do those terms refer to?  In aqueous solutions, compounds can exist as molecules (undissociated) or ions (dissociated).  When an acid or a base exists in solution nearly completely as dissociated ions, we refer to that acid or base as strong.  A weak acid or base will donate ions to the solution, but will remain primarily as undissociated molecules.

Notation:

Acids are abbreviated HA, with the H representing the proton (H+) the acid donates to the solution.  The A is referred to as the acidic anion (A-) that is left in solution as the proton is donated.

Strong Bases are abbreviated MOH, with the OH representing the hydroxide ion (OH-) the base donates to the solution.  The M is cation (M+) that is left in solution as the hydroxide is donated..

Autoionization:

Even without any acid or base added a very small number of water molecules will form protons (H+) and hydroxide ions (OH-).  The protons will then form hydronium ions, the acid ion.

Procedure: PhET Simulations à Play With Sims à Chemistryà Acid-Base Solutions à  

The concentration of the acids and bases used in the  at 0.010 (10^-2) Molar.

·         Begin with a strong acid and lower the pH probe into the beaker.  What is the pH of this solution? 

·         Test this strong acid with both pH paper and the conductivity probe.  What color does the pH indicator become?  Is this strong acid an electrolyte?  Does current travel through this solution?

·         Repeat the above tests with the weak acid, the strong base, and the weak base, and water.  Collect your observations in the table below:

	Strong Acid	Weak Acid	Strong Base	Weak Base	Water
pH meter read (value)	2.0	4.50	12	9.50	7.0
pH paper (color)	Pink or #2	Orange 4	12 teal	9 green	7 orange
Conductivity (bright/dim/none)	Bright	dim	bright	dim	Very dim
Exists as Mostly (ions/molecules)	Ions	Molecules	Ions	molecule	molecule

Procedure:

This simulation allows you to change the concentration of a strong and weak acid and base.

Complete the table below for some strong acids and bases and weak acids and bases by adjusting the concentration.

Strong Acids

Strength	Initial Acid Concentration (mol/L)	[HA] (mol/L)	[A-] (mol/L)	[H+] (mol/L)	pH
	.010 M	negligable	55.6	1.00 X 10^-2	2.00
	.050 M	negligable	55.6	5.00 X 10^-2	1.30
	.100 M	negligable	55.5	1.00 X 10^-1	1.00
	1.00 M	negligable	54.6	1.00 X 10^0	0.00

Weak Acids

Strength (approximately)	Initial Acid Concentration (mol/L)	[HA] (mol/L)	[A-] (mol/L)	[H+] (mol/L)	pH
	.015 M	1.50 X 10^-2	55.6	3.87 X 10^ -5	4.41
	.150 M	1.50 X 10^-1	55.6	1.22 X 10^-4	3.91
	.015 M	1.36 X 10^ -4	55.6	1.49 X 10^-2	1.83
	.150 M	1.17 X 10^-2	55.5	1.38 X 10^-1	0.89

Strong Bases

Strength	Initial Acid Concentration (mol/L)	[MOH] (mol/L)	[M+] (mol/L)	[OH-] (mol/L)	pH
	.010 M	negligible	1.00 X 10^-2	1.00X10^-2	12.00
	.050 M	negligible	5.00 X 10^ -2	5.00 X 10^-2	12.70
	.100 M	negligible	1.00 X 10^-1	1.00 X 10^-1	13.00
	1.00 M	negligible	1.00 X 10^0	1.00 X 10^0	14.00

Weak Bases

Strength (approximately)	Initial Acid Concentration (mol/L)	[B] (mol/L)	[BH+] (mol/L)	[OH-] (mol/L)	pH
	.015 M	1.50 X 10^-2	4.20 X 10^-5	4.20 X 10^-5	9.62
	.150 M	1.50 X 10^ -1	1.33 X 10^-4	1.33 X 10^-4	10.12
	.015 M	2.80 X 10^-4	1.47 X 10^-2	1.47 X 10^ -2	12.17
	.150 M	2.14 X 10^-2	1.29 X 10^-1	1.29 X 10^-1	13.11

Conclusion Questions:

1.      A strong acid is very concentrated / exists primarily as ions. (circle)

2.      A weak base is a nonelectrolyte / weak electrolyte / strong electrolyte.

3.      A strong base is a nonelectrolyte / weak electrolyte / strong electrolyte.

4.      At the same concentration (Molarity) a strong acid will have a higher / lower / the same pH as a weak acid.

5.      As concentration of a weak acid increases, the pH increases / decreases / remains constant.

6.      As concentration of a weak base increases, the pH increases / decreases / remains constant.

7.      As the concentration of a weak acid increases, the number of ions increases / decreases / remains constant.

8.      As the concentration of a weak acid increases, conductivity increases / decreases / remains constant.

9.      As the strength of a weak acid increases, the proportion of ions to molecules increases / decreases.

10.  As the strength of a weak acid increases, the conductivity increases / decreases / remains constant.

11.  What are the pH values of a weak acid with a concentration of 0.10 and a strong acid with a concentration of 0.01, ten times lower?     Weak acid, 0.10 M :____4.00________         Strong Acid, 0.01 M :____2.00________

12.  Explain the significance of the results of your calculation above. ___I was surprised to find that the Ph value is higher in weak acid than in strong acid. I was expecting it to be the other way around but because of the ion concentration it creates this. _______________________________