Week 37 – Acids and Bases

Welcome to Week 37!  This week, we will tackle the topic of acids and bases.

Last week was the latest in a long string of really tough weeks for our country.  Rather than try making a light-hearted video introduction, I am simply asking you to visit the Future Voter registration page on the Washington Secretary of State website.  You can register to vote as early as age 16, and then you will be able to vote once you turn 18.  Vote for the country you want and vote in every single election.  While you are waiting to turn 18, remember that every dollar you spend is also a vote in support of wherever your money was spent.  Be intentional with who you choose to give your money to.  Your vote is your voice – scream!

  1. Week 37 Attendance Check-In (required by 10am 6/5)
  2. [H+] and pH (pH Concepts Google Form assignment)
  3. pH Indicators (pH Analysis Gizmo)
  4. pH Lab@Home (optional bonus credit lab)

You did it!  Just to make sure, here’s a checklist of items you must complete this week by Sunday, June 7 at 11:59pm:

  • Week 37 Attendance Check-In (school district requirement)
  • pH Concepts (worth +10 assignment points)
  • pH Analysis Gizmo (worth +20 assignment points)
  • Optional pH lab (worth +40 bonus lab points)

Remember, you can email me any time.  Office hours for Science are Tuesdays from 11am-12pm and Thursdays from 1pm-2pm.  Check your student Gmail for Zoom instructions.

Don’t forget to complete the Week 37 Bonus Credit Opportunity!  For a complete list of all of the bonus credit opportunities, bonus assignments, and bonus lab reports offered during distance learning, click here.

Week 37 – pH Lab@Home

If you have access to some red cabbage and a few household solutions, you have what it takes to prepare the cabbage juice indicator shown in both Tyler DeWitt’s “magic trick” and Mr. Swart’s Week 36 introduction video.  Either way, earn up to 40 bonus points in the lab portion of your grade by documenting your efforts to:

  1. Prepare red cabbage indicator
  2. Observe after adding baking soda to the indicator
  3. Observe after adding an acid to the indicator
  4. Observe after adding a base to the indicator
  5. Observe after adding an acid to the indicator, followed by baking soda
  6. Observe after adding a base to the indicator, followed by baking soda

To earn the full bonus credit, document all of your work as a lab report and share it with Mr. Swart at david.swart@g.highlineschools.org.  Before you begin, review the Week 34-35 bonus credit lab report post and recall what happens when you mix baking soda and vinegar (an acid) – it gets messy!  That post includes videos, lab report requirements, and lab report templates you are welcome to use as appropriate.  Have fun!

Return to Week 37 – Acids and Bases and continue working.

Week 37 – [H+] and pH

The words acid, base, and neutral are all familiar.  By now in your schooling you have probably learned that water is a neutral substance, lemon juice is an acid, and bleach is a base.  You may have been introduced to the pH scale where you learned that water has a pH of 7, while acids have a pH of between 0 and less than 7 and bases have a pH of greater than 7 up to 14.  In fact, the pH of lemon juice is around 2.0, while the pH of bleach is around 12.6.  Lemon juice is a fairly strong acid, while bleach is a strong base.  Your blood has a pH of 7.4, making it slightly basic.

So what exactly makes something an acid or base?  Why are some acids and bases stronger than others?  Click the image below (or just click here) and read all about the relationship between hydrogen ion (H+) concentration and pH.

Acids-and-Alkalis-The-pH-Scale

Next, watch the video below from Mr. Anderson at Bozeman Science:

 

Finally, complete the pH Concepts Google Form assignment and show what you know about acids, bases, and pH.  When finished, return to Week 37 – Acids and Bases and continue working.

Week 37 – The Origin of Humans

We conclude our study of evolution with at a look at our own evolved humanity.  Watch the video below, focusing your attention on both the evolution-related content as well as on the types of jobs you see people doing.  Can you imagine yourself pursuing any of the careers shown?  After watching the video, complete the Origin of Humans Google Form assignment with questions about the video.  The video is also embedded in the Google Form assignment so you can easily reference it when answering the questions.

Next, it’s time to visit the Australian Museum.  The staff there have assembled an amazing collection of resources to extend your learning about human evolution.  Before you go, here’s the assignment:

  1. Read an article from the collection.
  2. Summarize your learning about the article in the Human Evolution Google Form.
  3. Repeat steps 1 and 2, but with an article from a different group of articles.  For example, if you read an article from the first group (Becoming human), your next two articles must be from other groups (for example, Where do we fit in? and Meet the family).
  4. Click here to visit the museum.
  5. Fill out the Google Form for your articles (worth +10 assignment points each)

When finished, return to Week 37 – Human Evolution and continue working.

Week 37 – Bonus Credit Opportunity

This week’s bonus credit opportunity is called, “Movie Time!”  To earn +10 bonus credit in the assignment category, you must share with me the title, a brief summary (must be your own writing!), and an explanation of why this movie is your all-time favorite science-related movie.  Click here for the bonus credit Google Form.  I will compile submissions into an anonymous list of movies and summaries below so we all have a resource to come back to this summer.

Weeks 37 – Human Evolution

Welcome to Week 37!  This week, we will step back in time and learn about the human branch of the evolutionary tree.

Last week was the latest in a long string of really tough weeks for our country.  Rather than try making a light-hearted video introduction, I am simply asking you to visit the Future Voter registration page on the Washington Secretary of State website.  You can register to vote as early as age 16 so you can then exercise your right to vote as soon as you turn 18.  For many of you, turning 16 is still a year or two away.  Remember, you also cast your vote every time you spend money.  You have a choice about where to spend money, so make sure the money you spend is going to people, businesses, and causes that are worthy of your support.  Finally, commit to lifelong learning.  Your high school education is just the beginning.  Please make the most of it.  Education opens doors you may not even realize are there.  Be brave, open all the doors, and keep them open for all who come behind you.  Let’s get to it.

  1. Week 37 Attendance Check-In (required by 10am 6/5)
  2. The Origin of Humans (two Google Form assignments)
  3. The Science of Evolution (optional learning extension – no assigned work)

You did it!  Just to make sure, here’s a checklist of items you must complete this week by Sunday, June 7 at 11:59pm:

  • Week 37 Attendance Check-In (school district requirement)
  • Human Origins Google Form (worth +15 assignment points)
  • Australian Museum Article Summary Google Form (worth +30 assignment points)

Remember, you can email me any time.  Office hours for Science are Tuesdays from 11am-12pm and Thursdays from 1pm-2pm.  Check your student Gmail for Zoom instructions.

Don’t forget to complete the Week 37 Bonus Credit Opportunity!  For a complete list of all of the bonus credit opportunities, bonus assignments, and bonus lab reports offered during distance learning, click here.

 

Week 37 – pH Indicators

To determine whether a solution is an acid, neutral, or a base, we need a tool.  In the lab, we can use a pH probe to obtain a quantitative pH value (an actual number).  Back in the day, we used pH strips to estimate the pH of different solutions.  Some strips are more sensitive than others, but the common theme is the strips rely on the user matching the color of the strip to a color chart which then estimates the pH.

At home (or in high school classrooms with limited funding) we can create a colorimetric indicator using cabbage! Colorimetric pH indicators provide us with a semi-quantitative measurement of pH.  By comparing the color of the indicator to a scale showing the color at a known pH, we can estimate the pH visually.  Color alone would be a qualitative data point (a description) while matching the color to a number provides us with a quantitative data point (an actual number).

To be fair, scientists use laboratory-grade colorimetric indicators in the lab all the time, and then use machines called spectrophotometers to quantitatively determine the optical density of the light passing through…remember the ELISA post from last week?

If you watched the Week 36 Intro video, you will soon realize that it also introduced you to this part of our lesson.  Prepare to be dazzled by the wizardry that is red cabbage juice indicator:

What is the actual chemistry behind red cabbage juice indicator?  Click the picture below and find out:

Making-a-Red-Cabbage-pH-Indicator

You now have what you need to complete the pH Analysis Gizmo.  The Gizmo was sent as a PDF attachment on Monday morning at around 8:00 am to the Week 37 – Chemistry Lesson email.

Anticipated answers to the question, “How do I turn in the Gizmo?”

  • If you have access to a printer, print the Gizmo and then:
    • Scan and email your completed work to Mr. Swart
    • Send pictures of your completed work Mr. Swart
    • Insert pictures of your completed work into a Google Doc and share with Mr. Swart.
  • If you do not have access to a printer:
    • Write answers on a piece of paper and then see above.
    • Write answers in a Google Doc and then see above.
    • Add comments to the PDF and share with Mr. Swart
    • This is 2020 – get creative!

Extend your learning!  For more on acid-base indicators, read Lesson 117 in the online textbook.  Note: this is not an assignment and you are not required to turn in any work related to lesson 117.

Return to Week 37 – Acids and Bases and continue working.