How cold is cold really?

Introduction
This activity-based approach is based on the idea that first-hand concrete experiences at an early age gradually strengthen the child’s capacity to construct abstract formulations.

Scientific concepts are to be arrived at mainly from activities and experiments. Science content at this stage is not to be regarded as a diluted version of secondary school science. Group activity, discussions with peers and teachers, surveys, organization of data and their display through exhibitions, etc. in schools and neighborhood are to be an important component of pedagogy. These points have to be catered to, which are also emphasized in the NCF 2005.

This module interweaves a story about three curious children, Asmabi, Vanaja and Nanjunda, who learn many things by observing, doing, inquiring and reflecting on their experiences. The characters like appa and ajja denote instances and points in the story where scaffolding is required. Questions stimulate students to observe and think beyond the book, while stories enliven their reading.

The module lays out a format for recording results of the activities and exercises. The same format enables continuous assessment of the student’s work.
This module is a way to discourage memorization of text, focusing instead on acquisition of tools of learning: namely, observation, design, drawing and construction, along with basic scholastic skills of speaking, reading, writing and calculating.

The segments called teacher’s corner has components called purpose, using the story and background content to enable the better usage of the text. While the purpose and using the story can be helpful for the teacher. The background content can be utilized by both the teachers and students to know more about the topic of discussion.





Asmabi: "Hi, Nanjunda, it’s really hot today. I am tired from playing lagori1. I want to drink something cold."

Nanjunda: "Me too. Would you want some nimbu sherbet?"

Asmabi: "That would be great. I like my drink really cold. Let us get ice cubes from the fridge."

Asmabi filled her glass all the way upto top with ice cubes and then filled it with nimbu sherbet and sat down to drink it. She didn’t take long to finish it and once she was done she threw most of the left over ice into the sink.

Nanjunda’s ajja2 was watching all this. "You know Asma, you don’t have to waste all that ice. Why do you put so much ice into your glass?"

"I like my sherbet really cold," she responded, "and the more ice I put in, the colder the sherbet gets."

"Are you sure about that?" asked ajja.

"Of course," answered Nanjunda. "It makes sense. More cold ice makes a cold drink, well … colder."

"Maybe," said her ajja "more ice might make it cool down faster, but would it really make it colder? Look! You threw away almost all of the ice!"

"It was cold enough, so I drank it all down. I can’t help it if all of the ice didn’t melt. Besides, if I let all of the ice melt, the sherbet would have gotten colder. Maybe it would have been too cold to drink. There was a lot of cold in the ice that had to go into the drink and the more ice, the more cold there was to cool the drink."

"I don’t know," mumbled her ajja. "Something doesn’t quite make sense here." Could the sherbet get colder than the ice that’s in it?"

"Well, I think so," Asmabi replied cautiously. "Or maybe not. I don’t really know. More ice would keep on making it colder as long as there was still ice, wouldn’t it?"

"We need to do some experimenting," said ajja. "We need a hypothesis3 or two. It looks like we have a least a couple of questions here." And he left the room muttering to himself.

When Vanaja reached she saw that Nanjunda and Asmabi were storming for ideas on different experiment can they do to understand the case of how ―cold can cold drinks become‖. Vanaja then came up with the following experiment. Let us try out the following activity together:

Activity:

Vanaja: "Let us add varying amounts of ice cubes to several glasses and then measure the temperature once the ice melts. Let us tabulate the readings and compare the readings to see if it supports our hypothesis or not."

Asmabi: "Yes!! Do you think the glasses should be of same size, with same amount of water? Also should the ice cubes be of similar size coming from the same tray?"

Vanaja: "I think…I think it will be easier for us to compare the results if these we kept these factors constant. What do you say?"

Nanjunda: "Aiyyo! But I don’t how to read temperature from a thermometer!"

Vanaja: "That is alright Nanju. Let us learn it now. ―Look carefully at the thermometer. Find the figures marked on the side of the glass. They are used to help you measure temperature. The numbers are called ……….."

Nanjunda: "Degree Centigrade!"

Vanaja: "That’s right Nanju. 10 degrees centigrade is written as 10⁰C."

"Now hold the thermometer up in front of you. Hold it firmly at the top of the stem. While reading the thermometer start at the bulb of the thermometer and follow the mercury thread up the tube."

Asmabi: "Guys, which thermometer do we use? There are two kinds. They look different."

Vanaja: "The one to the left is the traditional one and the one to the right is the digital thermometer. Here we are going to use the traditional thermometer."

                                

Nanjunda: "Yeah Yeah. All this is okay but I want to read the temperature of an actual substance."

Asmabi: "Let’s measure the temperature of cold water."

Vanaja: "Let us put the thermometer into the water so that the bulb is in the centre of the water. We have to make sure that the bulb is covered with water. And then we have to find the mercury thread in the thermometer."

Asmabi: "What number of degrees did the mercury stop at? This is the temperature of the cold water."

Nanjunda: "Now I understand! Let’s go back to the ice cube activity. Let’s make a table so we can put our hypothesis and observations in a table."

Please write down:
What do you expect will happen?

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Glass Number Number of Ice cubes Temperature Reading
     
     
     

 

What do you observe?

_____________________________________________________________________________________________________________________

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  1. Lagori: an Indian game involving a ball and a pile of flat stones, generally played between two teams
  2. Ajja: grandfather in Kannada
  3. Hypothesis: explanation used as a starting point for further investigation

Teacher's Corner

Purpose:
Heat and cold are often difficult concepts for children to understand. First, our everyday language gives them a tendency to such common misconceptions as cold being a substance that moves from place to place. How often have we told others to "Close the door, you’re letting the cold in?‖ Our colloquial language often reinforces the existence of ―cold energy," when it is scientifically acceptable to refer only to heat as a form of energy that is transferred from a warmer object to a cooler one and that cold is an absence of heat.

Secondly, the story tries to set the stage for discussions and inquiry into the nature of temperature and heat and to the fact that heat exchange is the cause of a phase change—when something goes from liquid to solid or vice versa. In essence this may be the students’ first encounter with the laws of thermodynamics.

Using the story
Using the story with grades 6 as a stimulus for discussion and then for the design of experiments to find out the answer to children’s dilemma. The discussion will probably produce ideas that can be further taken up for investigation and can be changed to questions and eventually hypotheses. The role of the teacher is to help focus the students’ thinking on designing experiments that will answer their questions or support or not support their hypotheses.

Background Content:
The most important lesson to be learned here is that the energy moves from a higher energy source to a lower energy source, and it is the heat that is transferred and not the ―cold.‖ It is important to realize that it takes energy to change a solid to a liquid and a liquid to a gas and that energy does not necessarily change the temperature of the substances involved. Building on it, adding heat to boiling water, once it is at a full boil, does not raise the temperature of the water. It will remain at 100°C at sea level. The added energy goes into continuing the phase change from liquid to gas and will continue to do so until the liquid is entirely evaporated. It will remain at 100°C at sea level. The added energy goes into continuing the phase change from liquid to gas and will continue to do so until the liquid is entirely
evaporated.


Krishna Srivalli U prepared this supplementary material for teachers for introducing heat to 6th graders.

It was a part of her course submission under Curricular Material Development at Azim Premji University.

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