Saturday, 23 September 2017

Detective Play Using Chromatography


Chromatography is a technique used to separate mixture into its individual components.
This method is commonly used to test ink, food colouring, and other coloured substances. It is widely used in a crime scene investigation. There are several types of chromatography, but we will only discuss paper chromatography.

Activity 1: Food Colouring

Objective: to test mixture of colours in food colouring

1.      Draw a line on a rectangular filter paper about 1.5 cm from the bottom by using pencil
2.      Put one drop of each food colouring (red, blue and green) on the line by using toothpick  
3.      Pour 20 ml distilled water into the beaker
4.      Dip the filter paper in the beaker and hang it by using toothpick
5.      Make sure the pencil line is above the water level.
6.      Wait 10-15 minutes
7.      Record your observations.

Results & Observation:


Red colour shows slightly orange at the top
Blue colour shows slightly purple
Green colour separates into blue and yellow

Discussion & conclusion:
Red food colouring shows the purest red colour, while green colour is a mixture.

Activity 2: Permanent marker

The steps are the same with Activity 1, only change the food colouring to marker.
We use 3 different colours (red, blue and black) from 3 different brands of markers.

From the results, the ink which traveled the highest is the most soluble in water.
Oppositely, the lowest distance traveled by the ink shows the ink is less soluble in water. So, buy that brand. You don’t want your writing easily wash away if it comes in contact with water, do you?
As for the mixture of colours, you have to test for yourself, as different marker gives different result. You may be surprise with the result.

Activity 3: Detective Play

I ask the students to draw a group symbol. It is hidden from other groups.
Each of the symbols is then put into an envelope.
Next, one group take one envelope (make sure they don’t get their own).
Now, they have to find out the owner of the symbol by testing the ink of the marker used.

Investigation steps:
The students get the sample ink from the note. They use the chromatography technique.
The result is then compared to the ink results from previous activity.
They should be able to find out the brand of the marker used and then name which group owns the symbol.

Out of 6 groups, 4 groups of students are able to state the correct owner of the symbol.
The fastest group with the correct answer is the winner.

Download the materials:

An Awesome STEM Workshop at RECSAM, Penang

On 9-11 August this year, I joined a STELR STEM workshop which was held at SEAMEO RECSAM, Penang. Since STEM education is actively progressing in Malaysia and has become more important day by day, so I took the opportunity to join the workshop to improve my teaching practice, especially in Science subject.

The workshop was joined by (plus minus) 50 participants from all over Malaysia, including teachers, lecturers, a headmaster, MRSM teachers and Petrosains staffs.

The workshop activities were conducted by experienced and skillfully facilitators.  They were:

Mr. Yuji Otsuka (Japan)
Mr. Edi Syahputra (Indonesia)
Ms. Nur Fitriana (Indonesia)
Ms. Nurazien Hj. Yahya (Brunei)
Ms. Suzanah Hj. Kurus (Brunei)
Mr. Norhailmi Abdul Mutalib a.k.a Cikgu Hailmi (Malaysia)

The opening ceremony of the workshop was launched by Dr. Nur Jayhan Ahmad, the Deputy Director of R&D in SEAMEO RECSAM.

After that, Cikgu Hailmi talked about STEM, its characteristics and also teaching and learning strategies for STEM. Next, we had a simple and quick ice breaking session handled by Cikgu Hailmi. Then we were divided into two groups for the rest of the workshop activities.

Here are some of the hands-on activities that we have done during the 3-days workshop:

1. Strongest Bridge Competition

This was one of the most interesting and enjoyable activity. We were given a bucket of newspapers, scissor and cellophane tape only. We need to use our own creativity to create a bridge model. Luckily, I’ve done this before with my students, so at least we got the basic idea.

After the bridges have been built, their strength was tested by using bricks.

final round: only the base of the bridge left..haha.... 

Surprisingly, my group has won the competition even though our bridge lack of creativity and art. Haha…..     

2. Water Treatment Process

I am sure teachers are very familiar with this activity. It is usually done during the topic of ‘water treatment process’ (Science KBSM form 2, chapter 5). Well, usually we will discuss the basic concept with the students, discuss the layer, which should be the first layer, which is the last, what type of substance should be used etc etc……right?

Here, we are given more variety of substances, including pebbles, stones, marbles, sand, tissue and cotton wool. We need to decide for ourselves for how many layers do we want and which substances to be used. We build 2 models, where one layer has become the manipulative variable. Then, we compare which model can produce clearer water.

From this activity, the students will be more independent and creative, but can still focus on the main purpose and concept. Teachers can make it as a project-based learning for students. 

3. Climate Change

This activity is related to global issues like global warming, ice melting and increasing rate of carbon dioxide in air.

How is ice melting affect South Pole and North Pole?

Since North Pole is located on the ocean (Arctic Ocean), the icebergs are floating on the sea surface. When they melt, the sea level does not much affect. (Concept of matter: occupy space).
However, South Pole is located on a continent (Antarctic). The ice sheet sits on the land surface with approximately 9,000 ft (2,700 m) thick. So, when the ice melts, it will increase the sea level.

After the introduction, we did some activity to test the effect of increasing rate of carbon dioxide to the surrounding temperature.

4. Natural Acid-Base Indicator

Chemistry lover will surely love this! We use purple cabbage to test acidity and basicity of a substance, and then arrange all the substances according to their acidity range.

How to prepare the indicator?
Just submerge the purple cabbage in the water overnight, and then use the water straight away. Or you can also blend the cabbage with water.

5. Conductive & Insulating Dough

Some students don’t like electricity topic (including teachers, I am one of them..hehe…).
So, how can we make the activity more interesting and encourage our students to build electrical circuits in a more creative way? Use conductive dough and insulating dough.

Conductive dough is a dough (commonly known as plasticine) which can conduct electricity, while the insulating dough cannot. It is because of the ingredients, where the conductive dough uses acidic substance (lime / lemon) as one of the ingredients.

Preparation of conductive dough was shown by our facilitators, while we prepared the insulating dough which was much easier. After that, we create an electrical circuit by shaping the dough into whatever shapes we like and connect it with colourful LEDs.

the colourful ones are the conductive dough, while the plain coloured is the insulating dough 

my group's product 

Products from other groups: 

We can also do this activity at home with our children. Making the dough ourselves make it  less harm, less chemical and less cost. 

6. Renewable Energy: Solar & Wind

This slot was conducted by Mr. Yuji Otsuka from Japan, a well-known country for their sustainable development using renewable energy. The activities were experimental-based. We did two experiments, one for solar energy and another one for wind energy. The objectives of the experiments were to find out at what angle and position of the solar panel and windmill that can produce highest energy.

if only my physics lecturer explained to me like this during my years in univ. 

building a windmill 

solar energy converted to sound energy 

7. Project-based Learning (PBL)

We did a project using recycled car toys to form electrical energy from kinetic energy of water. 

You can see the details in the video HERE 

To be honest, only after I attend this workshop I can fully understand the differences between problem-based learning and project-based learning. Both are called PBL, quite similar but differ in some ways.

In problem-based learning, students are more independent; they think of the problem / issue by themselves and come up with suggestions / solutions for the issue.

In project-based learning, they must create a product and the teacher can guide students along the way. Refer to the diagram below:   


I am so grateful for taking the opportunity to attend this workshop. It was really worth taking 3 days off from school and to travel all the way from Sibu-KL-Penang. The experience was really great and I learnt a lot about STEM approach. It’s not enough just by attending common 3-hours course where we just sit and listen. Teachers need more hands-on workshop like this.

All the activities during the workshop were carefully prepared by our dearest facilitators based on the module from ATSE (Australian Academy of Technology and Engineering). Some of the activities were altered to make it simpler and easy to handle with minimal cost.

I share the activities here so that the other teachers who didn’t get to attend the workshop can also get the benefit from it. But all the credits go to ATSE, SEAMEO, RECSAM, all the facilitators and the participants. And of course, getting the idea through reading cannot be the same with first-hand experience. So, if you are interested to attend a workshop like this, like and follow SEAMEO RECSAM (Malaysia) on their official FB page.

Lastly, I would like to express my gratitude once again to RECSAM Penang for organizing this wonderful workshop, to Dr. Nur Jayhan, the kind-hearted secretariat Ms. Tiana and all the great facilitators. Just like what I said during the reflection slot, from scale 1-10, I give 11 for my overall experience.

Last but not least, to all my group members specifically and all the participants generally. It was great knowing all of you guys.

my awesome group members: anita, shima, kak faridah & kak siti baizura 

Thank you. Until we meet again………..

* STELR: Science and Technology Education Leveraging Relevance
* STEM: Science, Technology, Engineering and Mathematics
* SEAMEO: Southeast Asian Ministers of Education Organization
* RECSAM: Regional Centre for Education in Science and Mathematics

External links & references:

Project: The GreenWall