SAVE OUR ICE KACHANG!

JACK'S PROBLEM......:(

JACK: I am an ICE KACHANG seller. I earn quite a bit with what i sell and my customers often come back for more. To improve business, i offer deliveries as well...however....

My ICE KACHANG always turn from this to....

THIS!!!! I need to do something about my ICE KACHANG or i'll lose all my business soon:(

What should i do???

CUSTOMER: Hey JACK! I can help you...come with me and we can seek help from my experimental group of friends:)

TO SOLVE JACK'S PROBLEM...

We decided to conduct an experiment to find out the ways in which we can keep ice kachang from melting too quickly. As we learnt in physics, conduction, convection and radiation affect the rate of heat transfer.

For this physics experiment, we made use of the concept of heat transfer to prevent heat gained by the ice kachang from its surroundings and heat loss from the ice kachang to the surroundings to look for materials to contain the ice kachang.

We used materials like...

Styrofoam box: Styrofoam is non-metal and a poor conductor of heat as it contains entrapped pockets of trapped air within its structure. As styrofoam is a non-metal, conduction occurs as a slow process of heat transfer. Air which is an insulator of heat, slows down the process of heat transfer even further. The white surface of styrofoam also affects radiation as it is a poor emitter and absorber of radiant heat[however this does not affect our experiment much as aluminium foil is used to wrap around the outer surface of styrofoam].

Aluminium foil: The shiny surface of aluminium foil affects radiation as it is poor emitter of radiant heat and absorbs radiant heat poorly as well.

Foam: Foam, like the styrofoam is an insulator of heat and has many little air pockets, which slows down the process of heat transfer through poor conduction of heat.

String: String is attached to provide convenience of carrying box around.

Covered box: The box is covered to prevent convection of heat out of the box.

All of the materials used are recycled,

to make full use of recycled materials for our box, we found out that some aluminium foil products can be recycled at around 5% of the original energy cost.

CONDUCTION

Conduction is the process of thermal energy transfer without any flow of the material medium. Heat conduction occurs as hot, rapidly moving or vibrating atoms and molecules interact with neighboring atoms and molecules, transferring some of their energy (heat) to these neighboring particles. In other words, heat is transferred by conduction when adjacent atoms vibrate against one another, or as electrons move from one atom to another.

This is because insulation prevents heat from passing easily through the walls of the styrofoam box. A well-insulated box can utilize less energy for heating, as the heat being created cannot escape outside and the heat outside cannot penetrate.

CONVECTION

Convection is the heat transfer process that involves the bulk movement of fluid molecules (current) that carry heat with them. Warm air rises and cool air sinks. As warm air is less dense that cool air, it is able to rise above cool air and take its place while the cool air will sink and the warm air loses heat while the cool air gains heat. With the change in density, the air will form a current and keep moving in a circular motion, heat is then transferred to different regions due to the difference in heat and density of air.

RADIATION

Thermal radiation is energy emitted Infra-Red radiation[electromagnetic waves] due to the pool of thermal energy that all matter possesses that has a temperature above absolute zero. Thermal radiation propagates without the presence of matter through the vacuum of space.

HOW DID WE CARRY OUT THE EXPERIMENT?

We wrapped aluminium foil on the four surface of the styrofoam box

Then we pasted recycled paper on all four sides of the inner surface of the styrofoam box as well as foam on the bottom surface of the box where we will lay the ice when we conduct the experiment, as well as on the cover to ensure that minimum heat is lost through conduction from the box.