Saturday, September 13, 2014

The calculator on the finger tips- Math trick

There is very convenient Math Trick to easily multiply the numbers from 6 to 10 using ones own fingers. We call this, calculator on the finger tip. It is used to teach children to learn tricks about multiplication time tables without any external resources. It also provides our students an opportunity to perfect it, anywhere and anytime just playing with their fingers after learning the trick.  
After teaching this trick in the class, most of the students who have struggled to memorize the times tables before, have admitted it to be very easy for them to calculate. It was amazing to see how handy the fingers are to calculate, besides providing mental calculation opportunity for an individual.
I remember how my students struggled to memorize the times table, especially starting from 6 to 9.  For some, they even took so long to memorize up to 5. Besides, it was of less practical memorizing, when there are gaps of few weeks and few months. The students keep on forgetting and they have to rememorize again (however not so difficult this time).    
So, in the following paragraph I am going to show you the trick. Well, first put your both hands in front of you and ascribe values from 6 to 10 to each finger starting from little finger to thumb. So, the values of  little fingers are 6, 7 for ring fingers, 8 for middle fingers, 9 for forefingers and 10 for thumbs.
How to multiply?
Step 1: Choose the numbers to multiply. For Example: 7x8   
Ste      2: Put together the fingers, whose values you want to multiply. Here, it is ring finger of the left hand and middle finger of the right hand.
Step 3: Now, count the touching fingers and the ones below them. Each of this finger will have the value of 10. So, if there are 5 fingers then the values are five times ten (5*10), which is equal to 50. Mentally retain this number in your head. 
Step 4: Now, multiply the fingers above the ones touching fingers. So, multiply 3 on left hand side with 2 on right hand side. We will get (3*2) 6.
Now mentally add 50 and 6 (50+6), the answer will be 56.
We can use this trick to calculate the times table of 6, 7, 8, 9 and 10, what amongst are the most difficult to calculate and memorize for almost all the students.

Tuesday, September 9, 2014


On last two Saturdays, our twenty students were drenched in sweat to make a vegetable garden and compost pit beside the residence of Drubgyud Tenzin Rinpoche. Rinpoche was very kind to offer his garden to the class as a learning space for the students. The continued monsoon rain in Dewathang has loosened the soil and it was quite easy for us to dig the earth. So far we have dug 20 small beds and we are getting set to sow seeds in a few weeks of time.
It’s been quite some time, waiting for a bright and dry day to begin work in the new vegetable garden. We will be experimenting in the garden with growing different seeds that are locally grown in Dewathang and also few other seeds from other place.
It was quite surprising for us to come up with long list of vegetables that can be grown in Dewathang: potato, eggplant, coriander, spinach, bean, pumpkin, squash, spring onion, cabbage, cauliflower, ginger, cucumber, tomato, radish, carrot, turnip, lettuce, etc. The list goes on. There are abundant vegetables we can grow in our garden.  
We also discussed about the right time to sow seeds in Dewathang. Students have pointed out that the summer season is usually not a good time for sowing seeds because of heavy rain fall. A few of them said we can sow seeds after blessed rainy day (which falls sometime in late September). Tshering Samdrup, a student from our class has called his parents, to ask about sowing seasons and few others have enquired to villagers. I'm happy to see how they take their responsibilities in learning.
It was quite a challenging for all of us, especially to make a bed on steep slope and leveling it, however with joined effort and cooperation we could managed to make the beds. The students have used unwanted logs and planks to make a supporting wall for the beds and to make it hold in a position they have used strong pegs.

Now, jointly we have agreed to sow seeds after the blessed rainy day. The beds are yet to finalize this weekend.

Tuesday, August 26, 2014

Stomp Rocket

The students brainstormed and played with the parts of the stomp rocket that I made for one of my science projects at The Exploratorium Teacher Institute training program in San Francisco. They had to figure out how to assemble it into the rocket stomp. I asked them an open ended question in the beginning to welcome their creative ideas and new designs from the rocket parts. So, I asked “what can you make out of these parts?’’ It was quite interesting to see the students collaborate their ideas and experiment assembling different models. They came up with different shapes of the alphabet (T, F, h), number (4) and other shapes with their own explanations.
After they tried every possible shapes and designs that they could think of, I asked them to come up with a model of a rocket stomp or a launcher. The students started to rush their ideas into remodeling a rocket stomp. After they figured out their rocket launcher, I gave them some guidance to make the launcher stable.
The next assignment was an art project to make a rocket out of paper or transparent little hard plastic cover or chart paper, cello tape and scissors. I demonstrated how to make a rocket using paper, and asked them to come up with their own designs and shapes for their respective rockets.
The students came up with their creative rockets: some are shorter, others are longer with tails attached and some are without a tail. Everyone was happy with their own rocket and assumed that their rocket would travel to the highest point in the sky. I have also seen students teasing each other with their rockets.
Finally, it was time for all of us to launch our rockets. We all went outside, in front of the guesthouse yard at Chokyi Gyatsho Institute and gathered around a rocket stomp. I told my dear boys that we are going to ‘’estimate’’ the distance travelled by each rocket. The word ‘’estimate’’ was introduced in the class with some daily practical examples (we estimate salt to add in the curries, etc.), before we came outside and they have quite a good understanding of this vocabulary. The students presented the launching of their rockets according to the alphabetical order of their names. Other students in the audience surrounded the rocket stomp, counted down from 3 to 0, while a stomper was ready to give a big stomp on the two liter plastic bottle to push the rocket into the sky.
In the process of launching, the students discovered how a rocket works in general and which of their rockets would travel the longest distance. They knew that a rocket with an attached tail travels further. They also said that a rocket with pointed head, slim, long, straight and airproof ones travel further.
After launching each rocket, I have asked them to estimate the distance travelled by that rocket. They came up with different estimations: 20 feet, 30 feet, 40 feet, 50 feet, etc.
Mr. Sangay Nidup’s rocket travelled the highest distance with an estimated height of more than 50 feet, followed by Mr. Dema Gyempo.

Sunday, August 3, 2014

Feel the temperature

When I was at the Exploratorium in San Francisco, I learned a technique for grouping students for activities in a class by shaking hands and feeling the temperatures. The temperature of human hands varies from individual to individual. Human hands can easily sense the temperatures of other hands.
To investigate we can ask our students to shake hands with other students in the class and notice the temperature of the other hands. Most likely, the students will have hotter or colder than their own hands. 
After shaking hands with many people, arrange them in a line from hottest hands at one end to coldest hands at the other. Then have the hottest handed person and the coldest handed person divide the line into two equal groups- Hot handed group and cold handed group. We can also extend this activity by making the hot handed person and the cold handed person go down the line shaking hands with everyone else to find out the differences.
What’s going on?
Human hands have different temperatures. The temperature depends on the metabolic rate and circulatory system of each individual. If a person’s vascular system is dilated (which is what we call vasodilatation), their hands tend to be hotter, if it is constricted (vasoconstriction), their hands tend to be colder.
We can also try this activity with an adult who smokes and drinks alcohol. First do the above activity then allow the smoker to take a break to smoke . When they return have them shake hand and experience the difference. Nicotine in cigarette smoke is a vasoconstrictor and will cause their hands to become cooler. On the other hand alcohol is a vasodilator and will cause their hand to become warmer. 
In addition to using this information for grouping a class, it can be the entry point to a number of lessons, from anatomy to physics even hygiene. Be sure to wash your hands after touching so many people, hands are the number one way to spread germs.

Tuesday, July 29, 2014

The Pinhole Investigation

The Pinhole Investigation is a very simple activity, but very affective to make students understand and confirm for themselves that the image that comes through a pinhole is reversed from top to bottom and left to right. This activity will provide our students with an opportunity to think and discuss why images appear in reverse, from top to bottom and left to right.
To make a pin hole, we need a sheet of black construction paper, 1 cardboard toilet tissue tube, 1 piece of aluminum foil, 1 piece of wax paper, and 4 rubber bands.
How to make
I will share how I made my pinhole at The Exploratorium Summer Institute Teacher Training Program. I placed the aluminum foil over one end of the toilet tissue tube and secured it with a rubber band. Then I placed the wax paper over the other end of the toilet tissue tube and secured it with a rubber band. Here we were instructed to be careful with the wax paper to keep it as smooth as possible because it is a screen.
Next, I rolled the black construction paper lengthwise around the tube, keeping the aluminum foil end exposed. The wax paper end of the tube became the middle of the black construction paper tube. Later, I came to know that the black tube has its purpose to allow us to see the images more clearly.
Finally, I used a pin to make a hole in the aluminum foil. We were told that sometimes the hole must be enlarged to see the image more distinctly, but it was better to start with a small hole and then make it larger if needed.
What next?
After making a pin hole, each student can take the viewer outside and look at houses, trees, cars, etc. through the open end of the tube. Ask this question to students: What do you notice?
We tried the viewer inside the classroom looking at one red and one green light bulb. We can also try it with a candle.
The following were a few questions we discussed in the class, and we can ask similar questions with the students: Why is the image reversed? How can I make it turn right-side up? How can I make the image clearer? How can I make the image larger? What if I used a larger tube, a longer tube, a larger hole, etc.?

Saturday, July 26, 2014

The Fan Cart

The classic physics problem, the action-reaction pairs in Newton’s Third Law can be explored from one of the projects I have made at The Exploratorium Summer Institute Teacher Training Program.
Let us ask a question to ourselves: “If a sailboat is stuck because there is no wind, is it possible to set up a fan on deck and blow wind into the sail to make the boat move?” The answer to this question can be solved by constructing a “Fan Cart” using simple materials, e.g. a cart, a motor, 4 CDs, a few drinking straws, a fan, a sail, straight round sticks, Velcro fasteners, a pair of small batteries and a battery case.
Make the fan cart look like the one in the pictures or you can design your own. 

Now notice the following observations:
1. Attach the sail and then attach the fan to the cart with Velcro so that it will blow air towards the sail when it is running. Turn on the fan, and observe what happens.
2. Leave the sail in place, but remove the fan assembly and turn it around (or leave the fan assembly in place and reverse the electrical connections to the motor), so that the fan will blow air away from the sail when it is running. Turn on the fan, and observe what happens.
3. Remove the fan assembly, and hold it in your hand while it blows air towards the sail. Observe what happens.
4. Replace the fan assembly so that it will blow air towards the sail when it is running, but then remove the whole sail assembly. Turn on the fan, and observe what happens.
5. Return to the original assembly, with the fan and sail both attached to the cart, and the fan blowing air towards the sail. Now insert a stiff piece of paper between the fan and the sail, and observe what happens.

What's going on?
Here is a summary of the first result from the situations above:
1. Cart doesn't move.
The behavior of the cart is a classic example of Newton's Third Law: For every action, there is an equal and opposite reaction.
In case 1, the fan pushes the air forward, and the air pushes the fan backward. A crucial thing to keep in mind is that the action and reaction forces - often called an action-reaction pair - do not act on the same object. If this was all that was happening, the cart would move backwards; the fan would be pushed backward, and since it's attached to the cart, the cart would be pushed backwards also.

Try to identify the action-reaction pairs in cases 2, 3, 4 and 5 and use them to predict why the cart behaves as it does.

Thursday, July 24, 2014

We can’t believe all that we see

Without a boundary, it's hard to distinguish different shades of gray. Sometimes we can't believe all that we see. Two slightly different shades of the same color may look different if there is a sharp boundary between them. But if the boundary is obscured, the two shades may be indistinguishable.
To try this experiment we can use the image provided below. Attach the white thread tail above the boundary between the two pieces, so that it hangs down and covers the boundary.
The tail like thread is used to obscure the boundary between two gray areas. We see one uniform gray area when the tail is in place, and two different gray areas when the tail is removed. But I have never seen the truth before the experiment. The truth in both gray areas is they are really identical in grades from light gray at one edge to dark gray at the other. In general, our brain ignores slight gradations in gray shades.
If we try this activity with our friends, most of them will see a uniformly gray piece of paper with a rope hanging down the middle.
What is going on?
Actually, the two rectangles are exactly the same. At the right edge both rectangles are light gray. Both become darker toward the left. Where the rectangles meet, the dark part of one rectangle contrasts sharply with the light part of the other, so you see a distinct edge. When the edge is covered, however, the two regions look the same uniform shade of gray.
It is difficult to distinguish between different shades of gray or shades of the same color if there is no sharp edge between them. If there is an edge between the two shades, the difference is obvious.
Your eye-brain system, however, condenses the information it obtains from more than a hundred million light-detecting rods and cones in the retina in order to send the information over a million neurons to your brain. Your eye-brain system enhances the ratio of reflected light at edges. If one region of the retina is stimulated by light, lateral connections turn down the sensitivity of adjacent regions. This is called lateral inhibition. Conversely, if one region is in the dark, the sensitivity of adjacent regions is increased. This means that a dark region next to a light region looks even darker, and vice versa. As a result, your visual system is most sensitive to changes in brightness and color.
When the thread tail is absent and the normal boundary is visible, lateral inhibition enhances the contrast between the two shades of gray. The bright side appears brighter and the dark side darker. When the tail is in place, the boundary between the two different grays is spread apart across the retina so that it no longer falls on adjacent regions. Lateral inhibition then does not help us distinguish between the different shades, and the eye-brain system judges them to be the same.