Essential chemistry – digital resources Chemistry e-Book

Nowadays e-books for studying become more popular. And from many sides, it is a very wise decision to use a centralized solution, which could be updated immediately if didactic or article author will found it necessary.

Worst practices

I have seen a lecturer who tried to make an e-book with students. It was fun for them to find materials on the internet. It really helps students to study. But soon lecturer recognized a very deep problem. The material chosen by students carefully verified. As a sample, you can find in YouTube video “How to make a MONOPOLE MAGNET”. In Brief in a Video to make monopole magnets recommended to take a regular magnet to freeze it in the refrigerator and cut it in half. If the student read it as a true source of information then he gets to know nonsenseand believe in that. .

Another group of lecturers from different countries agreed to make internal wiki by topics in English for Software development course. It was also very nice idea. And at the beginning it works fine, because of enthusiasms. But on the second year they start to find that materials is going old very quickly. So, it was a problem who will update the topic. Because every lecturer has they own style of giving materials to students. And appears different versions of topic. After that problem went deeper. Because it was already work routine and nobody was interested to edit an articles for free.

All that attempts shows that necessity in that tool exists, but it should be properly organized.

Best practices of E-books

The proper electronic book consists of two parts. One for the teacher and a second one for students. Of course, both parts are linked. And it gives the opportunity for young teachers to give lessons in a proper way immediately after becoming a lecturer. Just because the electronic book is the fully prepared tool for study subject. The properly prepared electronic book has a theoretical block, presentation for lessons, exercise book, test question, tips, video materials, files to research lab equipment and methodical guidance to a teacher. No doubt, that it should be allowed to control students study progress and trough tests and tasks and remotely help if they will need help.
According to that and educational standards are build up PASCO SCIENTIFIC Essential chemistry e-book. More information is here.

Concentration determination by colour

The Wireless Colorimeter and Turbidity Sensor – PS-3215 allows students to set up in seconds and collect measurements with ease.

How can you use light and color to determine the concentration of a solution by Beer’s Law? Explore and quantify the relationship between concentration and absorbance of light with the Wireless Colorimeter and SPARKvue software. Apply the relationship to determine the concentration of an unknown solution.

Read more about Wireless Colorimeter And Turbidity Sensor in product catalogue.

For purchase questions, e-mail ask@ste(.)education. (You must remove the brackets from the email address before sending).

STEM in Chemistry

Tie-dying is always a great year-end experiment and as chemists. A real bonding experience is fun to guess which student will end up with the most dye on their arms. Students also have an opportunity to incorporate chemistry in a meaningful way while creating a nice keepsake.

First, you’ll want to purchase reactive dyes since they are very brilliant and colourfast. They actually bond with the fabric, making the colour on the shirt last longer and the chemistry more interesting. Despite student protest that this is “just supposed to be fun”, tie-dying is an opportunity to review concepts of concentration, absorbance and transmittance. With a PASCO Wireless Spectrometer (PS-2600), you can explore the absorbance of the different coloured dyes before you start the process of colouring your shirts.

To really engage students in the technique of dying and in engineering process skills, the experiment can be opened up to student inquiry. Some things they could investigate as they try to create more vibrant colors include:

  • Comparison of reactive dyes, union dyes and acid dyes
  • Preparation and use of natural dyes
  • Comparison of synthetic and natural fabrics
  • Dying conditions like temperature, time and pH

To explore natural dyes create a yellow dye using turmeric, a red dye using beets, a purple dye using blackberries and a blue dye using red cabbage. It is possible to change the red cabbage blue by adjusting the pH of the solution. The results on the fabric are mixed, but because of the real-world application of science and engineering practices, the student learning is very real.  And if nothing else, everyone gets to take home a really cool shirt.

More labs with spectrometer

With the Wireless Spectrometer you can also perform these labs:

  • Emission spectra of light
  • Absorbance and transmittance spectra
  • Beer’s Law: concentration and absorbance
  • Kinetics
  • Fluorescence

Pasco Wireless Spectrometer

Watch the video below about Quick Start with PASCO Wireless Spectrometer (PS-2600).

Read more about PASCO Wireless Spectrometer in Product Catalogue.

For purchase questions, e-mail ask@ste(.)education. (You must remove the brackets from the email address before sending).

What is pH? Test the Rainbow in Chemistry class

Source: Pasco Scientific Chemistry blog March 2, 2017

Students often struggle understanding pH. While we can tell them that it is a logarithmic function, students are more likely to associate “logs” with a calculator button or a piece of wood. So how do we get them to understand what the pH scale really means? Look for a lesson, instead of a pot of gold, at the end of a rainbow.

Let’s start with the acids. First have the students pour 10 mL of 0.1 M HCl into a test tube. Using graduated cylinders and pipets they can add 1 mL of that solution to another test tube with 9 mL of water making a 0.1 M solution. They should repeat the process of taking 1 mL of the previous solution and adding 9 mL of water until there are 5 solutions. They won’t know it, but they just performed a serial dilution. Now they can add some universal indictor to the solutions for a splash of color. 

Indicators are nice, but they really are just an indicator. In this case the indictor was not able to distinguish between the first four test tubes. (Note to self: get some new universal indicator!). Since the true colors aren’t shining through, it’s important to remember that to really understand pH, your students need to take actual pH measurements.

Now comes the pH un part! After recording the data for the solutions, it is important for students to try to make some meaning out of those measurements. Time to dust off those concentration calculation skills. They should be able to calculate the concentration, and write the concentration of the acids in scientific notation.

Test tube table:
Test tube #Molarity of HCl (M)Molarity of HCl in scientific notation (M)[H+]
Value of the exponent of the [H+]Negative value of the exponent of the [H+]Color of solution with indicatorpH
10.101 x 10-11 x 10-1-11red0.97
20.011 x 10-21 x 10-2-22red1.70
30.0011 x 10-31 x 10-3-33red2.62
40.00011 x 10-41 x 10-4-44red3.61
50.000011 x 10-51 x 10-5-55orange4.83

No need to travel somewhere over the rainbow, all your students need now are some good guiding questions and they should see that pH is primarily based on the negative exponent of the concentration of H+. With this understanding, pH=-log[H+] can be something more powerful than just a formula to plug and chug in calculator.

You can even extend this activity to pOH and its relationship to pH if you drop the base. Following the same procedure students can perform a serial dilution starting with a 0.1 M NaOH solution.

After this colourful and engaging activity with the Wireless pH sensor and some fresh universal indicator, your students will be able to find the rainbow connection: a better understanding of the pH scale, what it means and how it’s measured. More information about PH sensor is here PS-3204.

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