espere ACCENT online magazine
Printer friendly version of this page
Home    ACCENT Educ.    Science    Encyclopaedia    es    ru    fr    de    it    cn   
Climate Change classes 1
UQ 3 May 07 Cars and ozone
UQ 2 Mar 07 Urban air
Climate change 2007 IPCC special
UQ 1 Nov Dec 06 Particles in air
Preface
Introduction
F: Perception of air
F: Phase transitions
F: Polarity and ions
R: Particle Measurement
R: Formation of S Aerosol
A: Combustion of plants
C: Information for teachers
Special: Oct. 2006 Communication
Nr 10 Sept. 2006 Africa's emissions
Nr 9 July 06 Air traffic
Special: June 06 Climate summit
Nr 8 April 2006 Ozone & N2 cycle
Nr 7 March 2006 Climate modeling
Nr 6 Feb. 2006 acid rain
Nr 5 Jan. 2006 oceanic sulfur
Special: Nov 05 Ozzy Ozone
Nr 4 Oct. 2005 light/satellites
Special: Sept 05 Cyclones
Nr 3 Sept. 2005 methane/energy
Special: July 05 Greenhouse Earth
Nr 2 June 2005 forest/aerosols
No 1 May 2005 vegetation/CO2
     
Aktivitäten

Combustion Experiments

We burn fir- twigs

In summer we often hear about forest fires in Spain, Portugal, other states in the Mediterranean, but also in other relatively dry regions in the world, for example in the West of the United States. During the burning process solid matter is transformed and transported to the air. We observe this in a fire experiment.
 


Part 1 – Determination of the weight loss

Material:

150 g dry plant material (here fir-twigs)
matches or pocket-lighter
a large plastic bowl
a fire place (here the pan of a grill)
a fire resistant vessel of sufficient size (here a baking tin covered with aluminium foil)
a fine balance
 

Material für Experiment

Material for the experiment
Photos: Elmar Uherek
All photos can be enlarged if you click on them.

Gewicht Tannenzweige

Weighting of the fir-twigs.

Procedure

We cut about 150 g dry plant material into small parts and measure the exact dry weight on a kitchen balance, for example in a large plastic bowl

We determine the empty weight of the burning vessel.

We put the twigs into the burning vessel (baking tin) and light them, if necessary with the help of some ethanol. They should be dry enough in order to burn down nearly completely.

After the end of the burning process we determine the weight of the formed ash in the burning vessel: weight ash = burning vessel with ash – burning vessel empty.

 

Leergewicht Verbrennungsschale

Weighting of the empty burning vessel

Verbrennungsvorgang

Combustion process. Attention, if you use dry fir-twigs the flames can turn up very high!
 

Results from a demonstration experiment:

Weight plastic bowl empty: 222 g
Weight plastic bowl with twigs: 362 g
Net weight plant material: 140 g

Baking tin empty: 314 g
Baking tin with ash: 321 g
Net weight ash: 7 g

From 140 g of plant material remain only 7 g ash.
 

Glimmfeuer mit Rauchentwicklung

Smouldering fire with strong development of smoke.

Gewicht der Asche

Weighting of the ash.

Interpretation

Question 1: Why there is much less mass from the ash than we had before from the plants?
Question 2: In which form does the missing mass escape?
Question 3: How long does the escaping mass remain in the air?
 

 

Part 2 – Collection of particles during the combustion

Material:

Dry plant material
matches or pocket-lighter
a fire place
a fire resistant vessel for the burning process
a vacuum cleaner
a larger funnel
a piece of white filter paper (as used for example in coffee machines)
adhesive tape
optionally a microscope

Procedure

The funnel is fixed with the tape on the intake tube of the vacuum cleaner in a way that the run out of the funnel is directed into the pipe. With the help of the tape the filter paper is fixed in the funnel so that the paper covers the hole of the funnel run out.

While the plant material is burning, the funnel is positioned close to the plume from the fire. (Attention, not too close to or over the burning zone.) The emitted air including particles is sucked trough the filter paper by the vacuum cleaner.

After 5 mins of sampling the changes on the filter paper are discussed.

If a microscope is available the clean filter and the filter after sampling can be compared under the microscope.

Result:

The combustion produces solid particles which are suspended in the air.

Interpretation:

Question: Which meaning does this experiment have for the reality?

 

 top

ACCENT / ESPERE

last updated 16.01.2007 | © ACCENT - Atmospheric Composition Change 2013