Data Logger

1.0 introduction.

Data logging is use in measuring and recording of physical or electrical parameters over a

period of time. Data loggers are widely used in a variety of applications such as in-vehicle data

logging, environmental monitoring, structural health monitoring, and machine condition

monitoring. Temperature, strain, voltage, current, pressure, force, and acceleration are the

common parameter of measurement that were used for data logging system. A system of data

logging would need three main components ( figure 1) that are sensor, data logger hardware and

computer.

Figure 1: components of data logging system

Data that is to be recorder by a data logging system is gathered using sensors. A sensor is

a device which measures a physical quantity such as the temperature and then sends a voltage to

the computer representing the quantity. There are two types of sensor that are digital and

analogue. An interface is put between the sensors and the computer. The interface converts the

voltages that the sensors produce into digital signals that the computer understands and protects

the computer from dangerous voltages. Most data logging software will perform two main

functions.  They will record data as it is collected, display and analyse data as it is collected and

after it has been collected.

A wide range of devices can measure and log data. It is done from basic, single

measurement devices to complex systems with built-in analysis functions and displays.

Moreover, many data logging applications are beginning to require the acquisition and storage of

other types of data, such as recording sound and video in conjunction with the other parameters

measured during an automobile crash test.

The differences between various data loggers are based on the way that data is recorded

and stored. The basic difference between the two data logger types is that one type allows the

data to be stored in a memory, to be retrieved at a later time, while the other type automatically

records the data on paper, for immediate viewing and analysis. Many data loggers combine these

two functions, usually unequally, with the emphasis on either the ability to transfer the data or to

provide a printout of it.

A data logger is an attractive alternative recorder or data acquisition system in many

applications. Data loggers have the ability to accept a greater number of input channels, with

better resolution and accuracy. Also, data loggers usually have some form of on-board

intelligence, which provides the user with diverse capabilities such as raw data can be analyzed

to give flow rates, differential temperatures, and other interpreted data that otherwise would

require manual analysis by the operator.

2.0   APPLICATION OF DATA LOGGING IN TEACHING AND LEARNING

In today’s society, young people’s motivation is of major importance in the decision to study

science and consequently in the choice of a career in this field. Schoolchildren’s views of science

are formed at a very early age (usually at primary school level) and these can have a positive or

negative impact on attitudes to science and technology (Osborne, Dillon, 2008). Therefore,

schools, teachers and the education system clearly have an important role to play here in

fostering a positive attitude to science.

Data logger and sensors used in experiment can motivate and increase interest of pupils

and teachers to learn and teach sciences. This is because data loggers automate the production of

graphs in experiments. A live graph display offers immediate feedback such that changes can be

monitored and technique adjusted. Data logging was usually a demonstration activity that took

place around other work.

There are advantages of using data logger in teaching and learning practice. The most

important impact is the use of data logging system in experiments had a positive impact on

pupils’ confidence with ICT. Instead, it is also positive to note that the teachers felt that the use

of sensors allowed learning for pupils at their own pace and speed, which would allow for better

education in classes where there are more advanced students alongside students who require

more time to grasp difficult concepts. This autonomous learning is not contradictory to the team

work which the sensors also enhance pupils worked together, supporting and helping each other.

Using computers to record data has a number of advantages over recording data

manually. First is measurements are always taken at the right time. Unlike a human the computer

will not forget to take a reading or take a reading a little bit too late and mistakes are not made in

reading the results. Humans can make errors when e.g. they read the temperature off a

thermometer. Instead, graphs and tables of results can be produced automatically by the data

logging software

2.1 EXPERIMENT OF MELTING AND BOILING POINT OF WATER

A)   ENGAGING PHASE

Figure 1 figure 2

Based on the two figure displayed, students are ask to guess what the pictures is about. They also

are asking for brainstorming about the similarity and the differences between the two pictures.

The similarity between the two pictures is both are example of change in state of matter

and required heat while the differences between the two pictures are the process and the change

of state occurs. Picture 1 shows boiling process where water is heat and become steam while

figure 2 is melting process where the state of matter change from solid to liquid.

B)    EMPOWER PHASE

Empower phase is the second phase in teaching and learning practice. Students construct

ideas and concept about momentum by carrying out an experiment. The following are the details

of the experiment carried out.

Title    : melting and boiling point of a substance

Objectives:

In this experiment, you will

1) use a computer to measure temperature

2) analyze graphs of your data to determine the freezing and melting temperatures of water

3) determine the relationship between the freezing and melting temperatures of water

Materials Used:

• Ice

• 250 mL beaker

• Bunsen burner

• Temperature probe (sensor)

• Computer

Procedure:

1. Place the ice in the 250 mL beaker

2. Place the temperature sensor in the ice. 

3. Connect the sensor to an interface box linked to the computer as shown in figure 3. 

Figure 3

4. Click the start button. Observe any transition process and the temperature they start to change. 

5. When all the ice melts, continue the experiment by placing Bunsen burner below the beaker

for heating the water as in figure 4

Figure 4

6.  Click the Statistics button. The temperature value for the selected data is listed in the statistics box on the graph.

RESULTS:

Data obtained by data logging

30 130 230 330 430 530 630

-50

0

50

100

150

200

Temperature, (oC) Time taken , seconds

-20 30

0 60

0 90

0 120

0 150

Based on the data obtained from data logger, students are ask to fulfill the following table and

identify the phase of experiment for every 30 seconds. They also must discuss why there has a

flat line in the graph. The results are in table below:

Table1: Heating of water

Time taken , seconds Temperature, (oC) Phase

30 0 Solid-liquid

60 0 Solid-liquid

90 0 Solid-liquid

120 0 Solid-liquid

150 30 Liquid

180 50 Liquid

210 70 Liquid

240 100 Liquid

270 100 Liquid-gas

300 100 Liquid-gas

330 100 Liquid-gas

360 100 Liquid-gas

390 100 Liquid-gas

420 100 Liquid-gas

450 100 Liquid-gas

480 100 Liquid-gas

510 120 Vapor

540 142 vapor

570 160 vapor

DISCUSSION:

          The melting process is a process where the solid phase changed to liquid phase under

specific pressure. The boiling process is a process where the liquid phase is changed to gas or

vapors phase. The substance used is water. The melting point of water is 0 oC and temperature

stay the same as the melting process occurred. When water is heated, the particles gain energy

and move faster as to move away their positions and begun to vibrate around each other.

In general, the temperature goes up the longer the heating continues. However, there are

two horizontal flat parts to the graph. These happen when there is a change of state.

The plateaus are also called phase changes. The first change of state is melting (changing from a

solid to a liquid).

Once the substance has reached the melting point there is a line stays flat for a period of

time, this is called a 'plateau' on a graph.  All the energy going into the system, being applied to

the substance, is being used to break the bonds of the solid and change the phase to a liquid.  This

conversion of phases takes a large amount of energy and therefore no temperature increase

occurs and the line is flat.  No increase in temperature occurs until all the bonds of the solid are

broken.  Once all of the substance has been converted to a liquid then an increase in temperature

is occur. The same occur when the temperature is at 100Oc. For water, it's liquid phase has a

very high specific heat capacity, therefore this is the longest line on a heating curve for water. 

C. ENHANCE

Students are group into 5 and every group is given a same problem statement to be discussing in

a group. The problem is ‘what happen to the heating curve if salt is added to the water? Discuss.

Salty water boils at a temperature above the boiling point of pure water (100°C). Other

impure substances behave in a similar way. The presence of an impurity in a substance lowers

the melting point and raises the boiling point of the substance. Melting point of An impure will

always be less than both of pure substance of either molecule. This is because the the impurities

prevent the substance from forming a crystal lattice, thus decrease its bond strength and lower

the melting point. While boiling point of impure mixture is higher because solution with

impurities has a lower volatility thus decrease the mole fraction of the solvent. Therefore, more

energy is needed to break the bond and boiling point is higher. In addition, the impurity also

reduces the ‘sharpness’ of the melting or boiling point. An impure substance melts or boils over

a range of temperature, not at a particular point.

D. CLOSURE

Students are asking to flashback what they had done in the class.

3.0 CONCLUSION

Data loggers help in better understanding of scientific experimentation. Other than that, the used

of data logger for determine the state of matter can get specific and accurate data reading that

might not be accurate due to parallax error when it is done manually.