A lot of of Polish schools have no data-logging and laboratory equipment. Some of teachers afraid of using ICT and data-logging equipment. Teacher training courses about teaching science withICT is not enough. How to help them?

Computer Assisted Education and Information Technology Centre in Warsaw (OEIiZK), Poland, in-service teacher training centre, organizes open lessons in physics, chemistry, biology, geography and elementary science. School students with their teachers attend the lessons carried out by teacher trainers. Students work in small groups. After a short introduction they perform data-logging measurements and analyse the respective graphs. The most exciting is the experiment ‘Energy emitted by a human body’.

It is designed to measure the rate of energy emission from the human body. In this experiment the different contributions to the energy balance of the human body can be measured and analysed. The experiment was devised by Mats Areskoug, and presented during the GIREP 2002 Conference in Lund (http://dspace.mah.se/handle/2043/6687). Similar experiment is used in the OEIiZK.

A thermally insulated box is prepared, containing sensors for temperature, humidity and CO₂ concentration. A data-logger records readings from the sensors whilst a person spends a few minutes inside the box. The rise in temperature can be obtained from the graph and used to calculate the heat energy output from the person’s body. The completion of the calculation requires a separate calibration experiment – a mains light bulb of known power output is placed inside the empty box and the rate of temperature rise again recorded using the data-logger.

Sample data from the graphs:

Duration of experiment: 300 s (5 minutes)
Increase in temperature:2.3 degrees Celsius, raising from 21.9 C to 24.2
Time for 100 W bulb to increase chamber temperature by 2.3 deg C: 418 s (6.97 minutes)

Temperature versus time graphs allow to assess the power from the rate of increase of the temperature, shown by the slopes of curves

Calculation of rate of heat emission

Heat emitted by 100W bulb in 418 seconds = 100 W * 418 s = 41800 J
Rate of heat emission by human body over 300 seconds = 41800 J/ 300 s = 139 W

The measurements of CO₂ concentration and relative humidity are useful as evidence supporting the chemical description of aerobic respiration in the body:

C₆H₁₂O₆+6 O₂ à 6 CO₂ + 6 H₂O

Further, the increase in CO₂ concentration can be used to calculate the amount of glucose metabolised during the experiment.  Since the Heat of Combustion (enthalpy) of glucose is known, the amount of heat generated by respiration may be calculated and compared with the result obtained from the rise of temperature. Calculations from sample data are included in Activity 3, described in the ICT for IST[1] module ‘Thermal energy and the human body’

http://ictforist.oeiizk.waw.pl/upload/Thermal%20Energy%20and%20the%20Human%20Body%20Module_EN.pdf

During the physics lessons about motion students not only take data-logging experiments using ultrasonic motion detector, but they also perform video measurements of the same phenomena and discuss the energy changes in an motion.

[1] ICT for Innovative Science Teachers project was coordinated by OEIiZK – http://ictforist.oeiizk.waw.pl/

Article by: Elzbieta Kawecka, Scientix Ambassador

Tags: data-logging, energy, experiment, laboratory, technology