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SCIENTIFIC PRACTICAL TECHNIQUES ASSIGNMENT 1 TITLE: INVESTIGATION OF SOIL. AIM: To calculate the percentage contents in the humus in soil. TASK 1(P4) The equipment used for this experiment is balance. Calculations of the soil experiment: Weight of crucible + soil = 25.66g Weight of crucible alone = 15.92g Weight of soil + water = 25.66g Weight of soil without water = 25.17g Work out the weight of water = 0.49g Workout the % water = weight of water x 100 Weight of soil and water 0.49x100 = 1.9 %water = 1.9 % 25.66 Weight of evaporating dish = 60.69g Weight of evaporating dish with soil = 114.98g Hot plate 150 Temperature increased to 400 after 5min Temperature after cooled weighed = 110.13g 54.29g of soil 49.44g of soil without humus 49.44g 54.29g x 100 = 91% TASK 2 (M4) The equipments were set up on the benches. The Bunsen burner plugged in the gas taps. Tripod and crucible is on top of it and stared to heat up the soil. Use the same sample and heated up the sample to burn off humus. ...read more.


Improving the accuracy of measurements buffer is to be washed each time of use. Labelling the solutions on the beaker and changing the solutions each time. To get accurate answers from the pH meters replace them with better quality pH meters. Repeating the experiment can give accurate answers. TITLE: RESISTANCE OF A WIRE AIM: To find out how resistance affect the wire as the length of the wire increases. TASK 1 (P4) The equipments used in this experiment are power pack multimeter and ruler. Table MEASURMENTS ( CM) AMPERE (A) VOLTS (V) RESISTANCE ( ) 10 0.61 0.08 0.13 20 0.58 0.19 0.33 30 0.58 0.28 0.48 40 0.61 0.40 0.66 50 0.61 0.50 0.82 60 0.58 0.58 1 70 0.57 0.67 1.12 80 0.57 0.75 1.32 90 0.59 6.90 1.53 TASK 2 (M4) Equipment was on the benches. Power pack plugged to the socket. Multimeters plugged to the power pack. Amps on 10A Volt on 20V Wires connected to the ruler and to the power pack. Other end of the wires connected to the multimeters. See the resistance of the wire. Take results down. ...read more.


The squares were found in the haemocytometer, before applying the dilution on to the haemocytometer. The measuring equipment was set up before using it the microscope was plugged in to the socket. The haemocytometer was on the stage of the microscope. The pippetor was measured accurate for the yeast and water. The experimental errors can be for this experiment that, the squares on the haemocytometer was not found before applying the dilution. The culture might have been added more then 0.9ml. Micro-organisms might not be counted correct. The haemocytometer might not be clean. It can be that not waited for 15 minutes or more than 15 minuets waited. Improving the accuracy of the experiment can be that make sure the squares on the haemocytometer is found. Be accurate when getting the culture with the pippetor. Get another person in group to count the micro-organisms. To avoid error in the results clean the haemocytometer before looking at it under the microscope and adding the dilution on it. More time is needed to get accurate results. More time to repeat the experiment. The websites I used for my images in my assignment is the following: http://www.advancegreenhouses.com/SM101.JPG http://www.electronichealing.co.uk/resources/Image/ph_test_paper.jpg http://balances.com/ http://z.about.com/d/modeltrains/1/0/D/-/-/-/Connect_Powerpack.png http://www.o-novavas.lj.edus.si/OsnovnaSolaNV/angl_ksenija/ruler.jpg http://images.google.co.uk/images?gbv=2&hl=en&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=Hemocytometer&spell=1 http://images.google.co.uk/images?gbv=2&hl=en&sa=X&oi=spell&resnum=0&ct=result&cd=1&q=multimeters&spell=1 http://images.google.co.uk/imgres?imgurl=http://www.williamsclass.com/Microscope%2520use/Images/JPG%2520Images/MicroscopeLabeled.gif&imgrefurl=http://www.williamsclass.com/Microscope%2520use/Microscope%2520use.htm&usg=__CO9k8O6DV0j6-ynY2hdYG1LOhm0=&h=441&w=472&sz=44&hl=en&start=3&tbnid=IBLNc48P3MC_rM:&tbnh=121&tbnw=129&prev=/images%3Fq%3Dmicroscope%26gbv%3D2%26hl%3Den http://www.people.cornell.edu/pages/jl265/pipette.jpg ?? ?? ?? ?? ...read more.

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