To show that food contains energy © A Walshe Page 1 Food contains chemical energy. When we eat, the energy in our food is converted into the energy we need to carry out our life processes. (There are roughly 4 joules in 1 Calorie) You will convert the energy contained in a walnut into heat energy in a test tube of water.
Apparatus: TI 83+ 50 cm 3 water CBL 2 Walnut Temperature probe Candle Boiling tube Tongs Place the temperature probe into the test tube of water, ensuring that it is close to the bottom, but not touching the glass. Set up the calculator to take temperature readings over time. PROCEDURE Plug a temperature probe into channel 1 of the CBL.
Turn on the CBL and calculator. Select the DAT AMAT E DAT AMAT E DAT AMAT E DAT AMAT E programme from the APPS APPS APPS APPS menu. Press Í ÍÍ Í at the welcome screen.
Press 8 to reset the programme. The CBL will check for probes. Screen 1 will be shown.
Screen 1 Select 1 : Se t u p 1 : Se t u p 1 : Se t u p 1 : Se t u p and press ... more. less.
the up arrow } to highlight MODE. Press Í ÍÍ Í to get screen 2 Screen 2 Select 2 : T i me g r a p h : T i me g r a p h : T i me g r a p h : T i me g r a p h to get screen 3 Screen 3 Select 2 : c h a n g e t i me s e t t i n g s 2 : c h a n g e t i me s e t t i n g s 2 : c h a n g e t i me s e t t i n g s 2 : c h a n g e t i me s e t t i n g s Enter 2 as time between samples in seconds Enter 60 as number of samples Press Í ÍÍ Í to get screen 4 Screen 4 Select 1 : OK 1 : OK 1 : OK 1 : OK to confirm settings, select 1 : OK 1 : OK 1 : OK 1 : OK again to return to the main menu. Weigh the walnut and record the mass Select 2 : ST ART 2 : ST ART 2 : ST ART 2 : ST ART The calculator will start to record data.<br><br> Use a Bunsen to light the walnut. Hold the walnut under the test tube. As soon as the data collection has finished, blow out the walnut.<br><br> The calculator will auto scale the data. As in Screen 5 Screen 5 To show that food contains energy © A Walshe Page 2 Use the |~ cursors to locate the minimum and maximum temperatures. Record these values.<br><br> Reweigh the walnut and record these values. Results Minimum temperature Maximum temperature Change in temperature Weight Change in temperature Per gram Processing the data Print a graph of change of temperature with time, and answer the following questions. 1.<br><br> Is there more or less energy in the walnut before it was burned than after it was burned? 2. Where did the energy from the walnut go?<br><br> 3. Is burning a walnut an exothermic or an endothermic reaction? 4.<br><br> In this experiment, the _______________ Energy in the walnut is changed to _________________ energy in the water.