Essay
applied science - unit 25 part 1 - chemistry - distinction level
- Institution
- PEARSON (PEARSON)
this is up to distinction level. this is the write up of my practical
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Chemistry fire investigationOxygen jar experiment
Aim- in fire investigation, the aim of the oxygen jar experiment is to determine if oxygen, a main
component in the fire tetrahedral, is removed then that the fire will cease to burn. We show this by
putting a beaker over a flame and waiting for the oxygen to be used up.
Equipment
A 100ml,250ml,400ml beaker, a small candle, lab coat, protective goggles, lighter, heat proof mat.
Health and safety
• Wearing lab coat with safety goggle
• Read any written work which includes warning before you begin
• Bags and coats must be left under the bench or completely out of the way
• Broken glass must be cautiously placed in the yellow bin provided
• Do not wear lose choses
• Tie hair back
Hazard
Bunsen burner: if not handled properly, you could have burned yourself or set some in fire. It is
advisable to remove any flammable material.
Glass beaker: if not handled properly, it could break and cut yourself. It advisable to keep glass
beaker away from the edges of table and be caution while moving them
The Variable
The independent variable for the investigation is the volume of the beaker while the dependent
variable is the time taken for the fire to cease to burn and the control variable will be the area the
investigation occurred, the stopwatches used, the type of candle used and the lighter use as it would
be the same through the investigation
Methods
I first followed the health and safety, making sure my environment is safe enough to conduct the
experiment and that I am wearing a lab coat and safety goggles. I then get out myself a fireproof mat
and places the candle on top. Using the lighter, I lit the splinter and used it to light the candles. Once
the candle has been lit, I used the 100ml beaker and record how long it too for the flame to out. I
repeated this 3 times and put all the data in a table. Repeat these steps for the 250ml and 400ml
beaker. After all the data have been collected calculate the average time taken for each beaker.
Size of beaker 1 (sec) 2 (sec) 3 (sec) Average
100ml 3.73 3.99 3.93 3.88
250ml 6.76 6.96 6.15 6.62
400ml 14.07 14.59 15.00 14.55
,Conclusion
This experiment show, that the fire tetrahedral was correct and that once oxygen, one of the 4 main
components, that fire extinguish. The fire tetrahedral is a diaphragm of a pyramid with each side
correlating to the element need for the fire to start. Fuel, heat oxygen and chemical reaction are the
element needed for a fire to start and if one side is removed the fire will cease to exist. This
experiment proves that the fire tetrahedral was correct because the jar limits the oxygen supply the
fire goes out. This experiment also show smothering is used as a method for extinguishing the fire
as the fire was subjected to confined space thus limiting the flow of oxygen.
Complete and incomplete flame
Aim- in fire investigation, the Bunsen burner experiment is used to determine that when there is a
large supply of oxygen, the flame will turn blue and became hotter while if there is a limited supply
of oxygen, the flame will turn orange and less to less hot compared to the blue flame
Equipment
Bunsen burner, fireproof mat, splinter and lighter
Health and safety
• Wearing lab coat with safety goggle
• Read any written work which includes warning before you begin
• Bags and coats must be left under the bench or completely out of the way
• Broken glass must be cautiously placed in the yellow bin provided
• Do not wear lose choses
• Tie hair back if needed
Hazard
Bunsen burner: if not handled properly, you could have burned yourself or set some in fire. It is
advisable to remove any flammable material
Variables
The independent variable for this investigation is the whether the hole is closed, open or half while
the dependent variable is the size, colours and movement of the flame and the control variable is
the location and the Bunsen burner as it will stay the same through the experiment
Method
I first followed the health and safety, making sure my environment is safe enough to conduct the
experiment and that I am wearing a lab coat and safety goggles. I then placed the Bunsen burner on
top of the fireproof mat and plugged the tube into the gas pipe. Use the lighter to lighter up the
splinter and then use the lit splinter to light up the Bunsen burner. Set the valve located ate stem of
the Bunsen burner open and record what you see. Do this step, for the valve being closed and half
, Hole Description
Closed Big orange flame
Open big blue flame
Half Blue flame with an orange tip
Conclusion
This experiment shows that open valve produces a complete combustion while the closed valve is
incomplete combustion. The combustion is complete when there is an ample supply of oxygen, and
the flame is bule compared to incomplete combustion when the is a limited amount of and the
flame is orange. The valve in the Bunsen burner controls the supply of oxygen to the flame, with the
valve being open allow oxygen to combust at 2 points compared to when the valve is closed to
oxygen can only combust ant 1 point.
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