2. TITLE
Data Logger : Pressure
INTRODUCTION
A data logger (data recorder) is an electronic device that records data over time or in relation to
location either with a built in instrument or sensor or via external instruments and sensors.
Increasingly, but not entirely, they are based on a digital processor (or computer). They generally
are small, battery powered, portable, and equipped with a microprocessor, internal memory for
data storage, and sensors. Some data loggers interface with a personal computer, and use
software to activate the data logger and view and analyze the collected data, while others have a
local interface device (keypad, LCD) and can be used as a stand-alone device.
Data loggers vary between general purpose types for a range of measurement applications to
very specific devices for measuring in one environment or application type only. It is common
for general purpose types to be programmable; however, many remain as static machines with
only a limited number or no changeable parameters. Electronic data loggers have replaced chart
recorders in many applications.
One of the primary benefits of using data loggers is the ability to automatically collect data on a
24-hour basis. Upon activation, data loggers are typically deployed and left unattended to
measure and record information for the duration of the monitoring period. This allows for a
comprehensive, accurate picture of the environmental conditions being monitored, such as air
temperature and relative humidity.
The cost of data loggers has been declining over the years as technology improves and costs are
reduced. Simple single channel data loggers cost as little as $25. More complicated loggers may
costs hundreds or thousands of dollars.
7. DISCUSSION
1. Based on the result from the tablets and graphs above, explain the relationship between the
surface area and the pressure exerted ???
The value of pressure (kPa) is influenced by the surface area. Smaller size of syringe (10 ml)
exerts greater pressure compared to bigger size of syringe (20 ml). As a conclusion, the smaller
the surface area, the greater the value of pressure exerted.
2. Compare the air pressure exerted on the 10 ml of syringe and 20 ml of syringe?
The pressure exerted on 10 ml syringe is greater than 20 ml syringe. For example, the value of
pressure for 10 ml syringe at 13s is 188.266 kPa compared to 20 ml syringe is 152.61 kPa. And
for your information, if you walk through snow, you usually sink into it. This is because your
shoes have a small surface area. Your weight is only spread out over a small area, so the pressure
on the snow is high. However, you will not sink so far into the snow if you are on skis. This is
because your weight is spread out over a greater surface area, so the pressure on the snow is low.
Drawing pins have a large round end for your thumb to push. The round end has a large area, so
it exerts a low pressure to your thumb. The sharp end has a very small area. The same pushing
force produces a high pressure there, so it pushes into the notice board.
If you swing round on one leg of a chair, you put four times as much pressure on one point of the
floor as you do if you sit properly. This is because four chair legs spread the pressure over four
times more area than one chair leg can
ENHANCE
8. Ryan does feel pain when he sits on a single nail instead of sits on many nails. What is the
explaination of this situation ?
ANSWER
Siton a single nail
Sit on many nails
9. UNIQUE FACTS ABOUT PRESSURE
Siton a single nail
Sit on a single nail will produce
higher pressure. This will cause
pain to our back. The smaller the
surface area, the higher the pressure
exerted.
Sit on many nails
Sit on the many nails will produce
lower pressure. So, our back didn’t
feel pain. The higher the surface area,
the smaller the pressure exerted.
10. AIR PRESSURE
The gases in Earth’s atmosphere are made up of tiny molecules that are constantly crashing into
your body and trying to press it inwards. This pressing force is called air pressure. It is greatest at
ground level where there are most air molecules. At greater heights above Earth, there are fewer
air molecules and the air pressure is much less. It is possible to compress (squeeze) air, and this
is used to inflate vehicle tyres and to power machines such as pneumatic drills.
AIR PRESSURE IN TYRES
Heavy construction machines have large tyres for two reasons. The compressed air in the tyre
helps to absorb bumps, so the ride is much smoother than it would be with a solid wheel. Large
tyres also help to spread the weight of the machine over a much bigger area. This reduces the
pressure on the ground and stops the machine sinking into the mud.
WATER PRESSURE
Water behaves differently from air when it is under pressure. It cannot be compressed
(squeezed). This makes it useful for transmitting force in machines, using a system called
hydraulics. Water is also heavier than air, and an increase in water pressure affects humans more
than a drop in air pressure. Even with a snorkel or other breathing apparatus, it feels much harder
to breathe underwater. The water above you presses down from all sides on your body, so your
lungs find it harder to expand to take in air. The deeper you go, the more water there is above
you and the greater the pressure on your body.
CONCLUSION
11. Pressure is the mechanical force per unit area that a confined system exerts on its container. In
thermal equilibrium, it depends only on bulk properties, such as density and temperature, through
an equation of state. Here we show that in a wide class of active systems the pressure depends on
the precise interactions between the active particles and the confining walls. In general,
therefore, active fluids have no equation of state. Their mechanical pressure exhibits anomalous
properties that defy the familiar thermodynamic reasoning that holds in equilibrium. The
pressure remains a function of state, however, in some specific and well-studied active models
that tacitly restrict the character of the particle–wall and/or particle–particle interactions.
