chemistry

Chemistry: pH scales and acidity

DiScoro writes about inquiry-based learning, digital resources, and ways to encourage higher-order thinking. We focus on STEM education and the use of technology.

The PHET simulation pH Scales enables students to experiment with acidic and basic fluids.

Note that pH scale and acidity are complex concepts for students especially for primary school pupils. A lower pH value means more ‘acidic’ and a higher value means less acidic, or more ‘basic’.  Neutral is indicated by the pH value 7.0.

However, the simulation can help the students to familiarize themselves with the concept(s). The simulation can be used in grade 6 or 7. Depending on how much time you wish to spend and how much structure you wish to give, in addition to the simulation, you could encourage the students to experiment and discover the basics about pH values in fluids and its application in every day life.

Suggestions for tasks and experiments:

  1. Check out the different fluids available.
    Rank the fluids from most basic to most acidic before you start measuring. Write down your estimation.
  2. Measure the pH values for the fluids given and write the results in a table.
    Which fluids are closest to pH 7.0?
    What does it mean if  the pH value of a fluid is close to 7.0?
  3. Use water to dillute the fluids and try to make a fluid that is closest to 7.0.
    Write down what you have done to reach your result.
    Make a screencast of your closest result(s) and print it out.
  4. Can you dillute a basic fluid with water to a pH value below 7.0?
    Can you dillute an acid fluid with water to a pH value above 7.0?
    Try to explain the result?

Think beyond the simulation.

  1. How could you make an acidic fluid basic? In other words, how could you for example change the pH value of an acidic fluid from 5.0 to 7.5?
  2. a. Your body functions best if the pH value is neutral. How does your body manage this?
    b. With the knowledge about the pH value of your body, how can you support your body to remain healthy?

pH value paper strips

In addition to the simulation students could use pH paper strips to measure the acidity of fluids. It becomes particularly interesting if the fluids you use can be tasted. Students can describe the taste they experience. Use for example coca cola or other fizzy drinks, fruit juice, tea, milk, coffee, water. This real life experiment makes it possible to neutralise an acid/basic fluid using other chemicals, for example by adding bicarbonate (baking soda) to an acidic fluid.

battery hydrometer

Another interesting tool is a battery gravity hydrometer, which actually measures the acidity (pH value) of the battery acid. You could also say that it measures the gravity of the battery fluid. Together with a Volt meter it is used to check if the battery is charged and in good condition If your battery is fully charged the pH value should be near 1.28. If the battery is discharged, the pH value will be near 1.14. The battery hydrometer only measures accurate with pH values around 1.2. So is useless to measure pH values over 2.

More PHET simulations. See also Balancing Act, The moving man, Energy skate park, and Density and Buoyancy.

 Purchase  Free
 Hardware  PC, iPad
 Requirements  browser

 

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Technology and Design

DiScoro writes about inquiry-based learning, digital resources, and ways to encourage higher-order thinking. We focus on STEM education and the use of technology.

This time we write about Technology & Design as a school subject or project for students (grade 6 to 10). In several countries Technology and Design has become a school subject.
Most commonly students work on a task during more than one hour. The tasks are interdisciplinary and require many different skills: planning, sketching, creativity, safety, use of tools, research , construction, experimentation etc.
Technology is not limited to the use of digital technology. Technology & Design tasks have a strong practical component and aim at problem solving skills. By nature the tasks are often low floor-high ceiling tasks. This implies that it is clearly understandable what the goal is, all students are able to get started (low floor). At the same time the tasks offer enough challenges and opportunities to dive deeper both in creativity as well as in complexity (high ceiling).

To make a plan is usually a step in the process. It is up to the teacher to ask for a report of the process or not. This can be written, visual, oral, with the use of multi-media (photos, video) or a combination.

Topics that could be part of Technology & Design are

    • design and create a rocking horse for children age 2-3
    • make a piece of household furniture using recycled materials
    • make a gripper stick for waste picking, or for elderly people at their homes
  • engineering (using concepts from chemistry and physics)

Technology and Design will certainly focus on the new economy where circular design and production, and no or minimal waste, are the ultimate challenges and goals.

Video Science

DiScoro writes about inquiry-based learning, digital resources, and ways to encourage higher-order thinking. We focus on STEM education and the use of technology.

Video Science produced by by Science House offers a large number of short videos on experiments. The videos focus mainly on chemistry, but some videos are about phenomena from physics or other science areas.
Students can watch the video’s or carry out the experiments themselves., although some experiments require substances or equipment that will not be readily available. For you as a teacher the videos may inspire you to let show students the experiments. Of course it is even more more interesting and instructive if the students carry out experiments themselves in class.

The future for industry and society lies in recycling, and even a step further ahead in cyclic production, and cradle-to-cradle production. Particularly interesting are therefore experiments such as “Green plastic” and “Recycling paper”.

The latest App (version 4.0) is designed for iOS 6. Unfortunately the App does not work on iOS 11. Hopefully this will be resolved soon.

 Purchase  Free
 Hardware  iPhone, iPad
 Requirements  iOS 6  (not working on iOS11 !)

DaVinci Kindergarten

DaVinci Kindergarten is a pilot project in which we design, develop and try-out inquiry-based activities for children in the age 4-8. We have worked with children age 4-5 at two kindergartens in Norway. The activities focus on concepts from science, and technology and foster mathematical thinking.

We present some of the activities that have been developped. Contact us if you wish a complete description of the activity.

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  1. Show-box– sight lines and mirroring.
  2. How big is the panther? – measuring, human-based measuring units e.g. foot, thumb(=duym/inch), span (=fathom), step.
  3. How do you get the light on? – electricity, battery, light, lightbulb, lamp, electrical wire, curcuit.
  4. What weighs most/least? – experimenting with balance scales and different materials with the same volume and different weight.
  5. Discover more about your toys. What kind of materials are they made of? – Categorise, recognise, examine the different materials and discover their characteristics.
  6. Bee-bot – programming a robot.

Solubility in water

Water is the most important chemical substance on earth. Water has specific chemical characteristics unlike other substances. One of these characteristics is its solubility.

Students build an understanding of solution concentration by varying amounts of solute,
solvent, and solution. Students can investigate which substance can have the largest concentration (solves best) even if they do not know  the substance. This can be an introduction to a hands-on practical.

The students can observe the amount of mol/L (molecules that can be solved in one litre) and find out what saturated means? What can be observed when the solvent is saturated?

solubles

 Purchase  Free
 Hardware  PC
 Requirements  browser

Oplossen glazenDownload practical experiment on Solubility in water for primary school level.

 

bruistablet2Download practical on Solubility with the use of effervescent tablets.

Depending on how used the pupils are to carry out experiments, you can leave out some of the instructions (scaffolding). Purely inquiry-based would be:

  • Find out how you can influence the degree of solubility in water using the effervescent tablets and water.

Whereby the pupils have to set up the experiment themselves, record the results, and write a conclusion.

 

See the blogpost Density and Buoyancy for buoyancy in water.