Acid Rain

Grade Level & Duration:

/ 9 /

Subject:

/

Acid & Base and how acid rain deteriorate concrete structures

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Prepared By:

/ Amr Safwat

Materials Needed

pH indicators, pH probes, Vinegar, distilled water, Clorox, Nitric Acid, Beakers, 30 beakers, Safety Gloves, 1 bag of concrete mix,

Analyze Learners

Overview & Purpose (STEMcinnati theme)
Overview: During this lesson the students should understand how to determine and measure the pH of any substance. The students will have to use different measuring tools to measure the pH in different concentrations. Students will also learn about the impact of acid rain on the environment. The main focus will be on the change of pH in concrete structures when in contact with acid rain which reduces the pH and leads to corrosion of rebars.
ACS
A:Investigating, monitoring and controlling the amount of toxic gases releases tot eh atmosphere is one of the major application that humans have to deal with today and in the future. Controlling pH values and concentrations helps in protecting our built environment.
C:Civil engineers, marine engineers and environmental engineers all usepHto figure out how to change or maintain structures and the environment
S:Acid Rain has a huge impact on our society. Sulfuric acid which is part of acid rain dissolves some heavy metals. These heavy metals when is solution can have bad effects on living organisms and the environment. It can lead to health problems. Also streets and bridges can deteriorate and lead to accidents and major failures.
STEM will be addressed during the following four days as follows:
Science:Chemistry of pH and acid base reactions.
Technology: Reduction of production of toxic gases.
Engineering:Civil Engineering and Chemical Engineering
Math: The students will have to calculate change in rate. Measure weights, dimensions and change in pH valuesand plotgraphs.
Note: Each class unit consists of 90 minutes. This class is a two day class activity and part of the designing airplane wings. / Education Standards Addressed
Science 9.8Demonstrate that the pH scale (0-14) is used to measure acidity and classify substances or solutions as acidic, basic, or neutral.
9.9. Investigate the properties of pure substances and mixtures
(e.g., density, conductivity, hardness, properties of alloys,
superconductors and semiconductors).
Math: 9c. Solve and graph linearequations and inequalities.9.3. Use the ratio of lengths in similar two-dimensional figures or three-dimensional objects to calculate the ratio of their areas or volumes respectively.
8.h Solve linear equations andinequalities symbolically,graphically and numerically.
  • Information and Technology skills:Identify information problems to design, develop and evaluate information products and solutions. Use measured data points to sketch different graphs. Demonstrate that the pH scale (0-14) is used to measure acidity and classify substances or solutions as acidic, basis, or neutral. Participate in and apply the process of scientific investigation to create models and to design, conduct, evaluate and communicate the results of these investigations.

DAY 1– Test the pH of various substances

Select Goals and Objectives /

Teacher Guide

/

Student Guide

/ Assessment

Goals and

Objectives

(Specify skills/information that will be learned.) / Goals:
Understand how acid rain impacts our built environment.
Objectives:
  1. Determine the pH of different elements and solutions.
  2. Identify how acid rain changes the pH value and deteriorate building and bridges
/ Pre- and Post- assessment questions:
What is a base and an acid? How can we determine if a substance is acidic, natural or alkaline? What is acid rain and what impact does it have on everything surrounding us?

Essential question:What effects does acid rain have on humans and environment?

Concrete cube production: The teacher should buy all the material needed to produce standard size 2x2x2in concrete cubes. A bag of concrete mix can be purchased at any home improvement store. As molds small milk cartons can be used.

The cubes should be produced the weekend before the lesson.

Each group should get three cubes to be tested in three different solutions.

Select Instructional Strategies –

Information

(Catch, give and/or demonstrate necessary information, misconceptions, etc…) / Project based, interactive inquiry and student centered
(5 min) Catch:The teacher will bring dry cement or concrete mix and some small concrete cubes.
In the next step he will through the cement and the concrete cubes into a Nitric Acid solution. The cement and the cube should dissolve in that solution. The teacher will ask the students to explain to him what just happened.
Background Nitric Acid is a highly acidic and can dissolve some heavy metals. / Team work
Misconceptions:Strong acids have a higher pH than do weak acids. Neutralization always results in a neutral solution. A salt contains neither hydrogen nor a hydroxyl group, so its solution cannot contain hydronium nor hydroxide ions. PH is a measure of acidity but not of basicity.
Utilize Technology / PowerPoint pH scale, definition of acid and base and acid rain. /

Other Resources

(e.g. Web, books, etc.)
The pH scale ranges between 0 and 14, with 7 beingneutral. A substance with a pH less than 7 is acidic. If greater than 7, the substance is basic or alkaline. Each one-unit change in pH is a tenfold increase or decrease in the strength of the acid or base being measured. A unit change from pH 5 to pH 3 would be a hundred times (10 x 10) increase in acidity.
Acid Rain
Robert Angus Smith, an English chemist, first used the phrase "acid rain" in 1852 when he noted the connection between London's polluted skies and the acidity of its rainfall. Most Scientists agree that "normal" rainfall has a pH of 5.6. Rain in the atmosphere reacts with carbon dioxide (CO2) to form a weak carbonic acid, altering the rain pH to 5.6. Acid rain is defined as any form of wet precipitation which has a pH less than 5.6 (on a scale of 0 to 14, with 7 being neutral). The "rain" becomes acidic
when water molecules (H2O) react with gases in the air. These gases are primarily sulfur dioxide (SO2) and various nitrogen oxides (NOx). This combination of gases and water molecules takes place when the water captures (attracts) hydrogen ions (H+) from the gases (ions are electrically charged particles in molecules).


Require Learner Participation

Activity

(Describe the independent activity to reinforce this lesson) / (5 min) Pre-assessment
(5 min) Catch: Described under Instruction strategies.
(30 minutes)Activity 1:
Testing the pH of different solutions
  • Teacher needs to set up stations with different solutions.
  • Students will use pH probes pH indicator paper to compare both results.
  • The last station will have empty beakers to mix and dilute solutions.
  • Haveconcrete blocks ready to be dipped in solution.
(30 min)Project: Measuring pH over time
  • Teacher needs to prepare concrete three for each group blocks 2x2x2in
  • The students should measure the dimensions and weight of each cube and place each cube in a different solution.
  • Have same solution in three other beakers and put steel nails
(15 min) Cleanup:make sure all the tables are clean
(3 min) Review: Discuss with students how the acid rainhas an effect on the environment. / Students need go to each station and fill out the table in their packet.
  1. Students should follow the instructions given by the teacher
  2. They will take vinegar and a Clorox solution and dilute with distilled water. By adding each time 50ml of distilled water three times. At the end they will have added 150ml of water.
  3. The students should measure pH values.
  4. Students will work on their project
  5. Students will study how pH of different solutions changes over time when concrete blocks and steel nails are placed in these solutions.
  6. The students will prepare three pairs of different acid solutions in each pair a steel and a concrete nail will be placed.
  7. Students will have to measure the pH over a period of week once every two days and note down their measurements.
  8. Review with students what they learned on that day.
/ Solutions at different stations: lemon juice, white vinegar, soap, baking soda, soft drinks, mineral water, and milk

Evaluate (Assessment)

(Steps to check for student understanding) – See Objectives above / Pre- assessment questions:
  1. What is a base and an acid?
  2. How can we determine if a substance is acidic, natural or alkaline?
  3. What is acid rain and what impact does it have on everything surrounding us?
/

Additional Notes

Ways to purchase

DAY 2 – Measuring the pH in solutions and concrete cubes and plotting and evaluating data

Select Goals and Objectives /

Teacher Guide

/

Student Guide

/ Assessment

Goals and

Objectives

(Specify skills/information that will be learned.) / Goals:
Understand why acid rain could be crucial to the build environment
Objectives:
  1. Describe the change of concrete pH over time.
/

Formative assessment: How does acid change the pH of concrete blocks?

Summative assessment:How is the pH related to the amount of toxic gases produces and emitted to the atmosphere? What did you learn during this activity?

Select Instructional Strategies –

Information

(Catch, give and/or demonstrate necessary information, misconceptions, etc…) / Interactive inquiry and student centered
Catch:Option 1: Show the students a video about the effects of acid rain. / Team work
Utilize Technology /

Other Resources

(e.g. Web, books, etc.)

Require Learner Participation

Activity

(Describe the independent activity to reinforce this lesson) / (5 min) Catch:Described under Instruction strategies.
(3 min) Review: Review what the students did during the last day.
(70 min)Activity 1:
  • Student should do some online investigation on the acid rain and answer the questions provided to them in the attached packet
  • Students will have to plot three graphs and answer some questions.
  • Discuss with students how engineers try to protect our atmosphere from acid rain
(5 min) Cleanup: Students will clean their desks.
(3 min) Review: Discuss with students how pH helps engineers to come up with predictions and solve problems / Students need to focus on the different parts of the given problem and they also need to make decisions which alternative they would go for.
  1. Students will measure the pH of the concrete cubes and the dimension and weight of each concrete cube and complete their data tables
  2. Studentsenter the data in an excel spread sheet and plot their graphs
  3. Students should discuss their measured results and come up with reasons and connect their results to real life.

Evaluate (Assessment)

(Steps to check for student understanding) – See Objectives above / (5 min)Summative Assessment:
Make sure the students understand the goal of this activity.
The teacher should also give them some hints to redirect the students. /

Additional Notes

Ways to purchase

Reflections:

This lesson had to be modified a few times. Initially, I wanted the students to use Nitric Acid to see how this would dissolve concrete. Since Hughes didn’t have a chemical lab with a hood it would have been too dangerous to have the kids run this experiment. I showed them how nitric acid dissolves concrete and let them use Coke Cola as the acid in which they had to place the concrete cubes. The experiment still went pretty well due to the fact the basic concrete cube reacted with the coke and neutralized the acid coke solution. This experiment helped me explain how an acid would decrease a basic solution over time and vise versa. Overall I can say that this lesson went well. The students had the chance to collect their own data and produce their own graphs. There was a time issue giving the fact that we had to walk the students to UC which took 15 minutes.