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Minor Versionm

by Procheta Mallik

Introduction

The phenomenon of a thermos used here is to minimise heat transfer due to conduction and radiation. The flask is made with a plastic bottle inside another plastic bottle separated by insulators.

    • Be very careful while using scissors and paper cutter, if required please take the help of an adult .

    • Dont use water hotter than 70*C as the plastic bottle tends to deform and shrink.

  1. One bottle should be able to fit into the other with no difficulty. Make sure that the inner bottle has a cap. Ideally, a 500ml and a 1l bottle.
    • One bottle should be able to fit into the other with no difficulty. Make sure that the inner bottle has a cap. Ideally, a 500ml and a 1l bottle.

    • Use scissors or paper cutter to carefully remove the very top of the larger bottle, cutting just below the neck.

    • The hole cut needs to be just large enough for the neck of the inner bottle to poke through.

    • Lay the larger bottle on its side and carefully cut it into half, leaving the bottom half just a little larger than the top half.

    • Cut crosswise across the bottle , not lengthwise .

    • Cut evenly around the bottle.

    • Roll the smaller bottle with one of the insulators, i.e. white paper or aluminium foil and tape it in place.

    • Rest the bottom of the smaller bottle inside the bottom of the top bottle centring the two together.

    • Fit the top half of the outer bottle over the bottom half so that the two overlap.

    • Insert the neck of the smaller bottle through the hole in your top outer half as you slide the top piece on.

    • Tape the top edge of your outer bottle onto the top of the inner bottle, sealing the two bottles as close to airtight as possible.

    • Repeat steps one to seven to construct another thermos with another insulator.

    • To check how long the thermos retains heat, pour hot water (~70C) into it and check the temperature.

    • Check the temperature again after an hour.

    • Make sure that the volumes of the two thermos flasks constructed are the same.

    • Also make sure that the initial temperature of the water in the two flasks and the time interval for testing the temperatures are the same.

    • Make sure that none of the bottles used have any holes.

    • Volume of the water in the variations done need to be the same to get readings that you can compare.

    • The time interval of the start time and the stop time of measuring the temperatures of the variations done should be the same to get readings that can be compared.

    • Fill out an observation table, like the one shown here

Finish Line

Vishal Bhatt

Member since: 04/26/2017

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