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FATS ASIDE WE ARE WHAT WE
EAT
An A level project on obesity.
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SOME FACTS ABOUT OBESITY..
BMI = (weight)/(height)²- 25 = overweight
- 30 = obese
What caused this?
- Excessive consumption of foods with high sugar and fats content
- Not eating! blood sugar decrease stress hormone stimulated body
tissues turned into sugar fuel not entirely burned up, stored as fats
What happens next?- Triggers several diseases like heart diseases, high cholesterol, high blood
pressure
- Self- conscious, low self-esteem
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WH AT CAN I DO TO PREVENT/CURE
OBESITY?
Maintain a healthy lifestyle!
Stay active!
- Exercise regularly but do not over-exercise
Keep a balanced diet
- Eat fast food only once in a while
- Less oil, less salt, more vegetables
- Avoid sugar
- Low calories
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EXPERIMENT TIME!
1. Test for presence of sugar in 2 unknowns
2. Determining of the energy levels of various samples
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1. BENEDICT¶S TEST!
Test for presence of reducing sugars Blue colour of solution given by copper(II) ions, Cu²+
At the end of the experiment, colour change indicates the (extent of)
presence of sugar
Blue 0% sugar
Green 0.5% sugar
Yellow 1.0% sugar
Orange 1.5% sugar
Brick-red >2.0% sugar
Used in urine test for diabetes
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CHEMICALS AND APPARATUS..
Benedicts solution Samples of X and Y
Test tube × 2
Test tube holder
Test tube rack
250 cm³ beaker
Dropper
Bunsen burner, tripod stand, wire gauze
Safety goggles
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PREPARING AW ATER BATH!
Fill the 250cm³ beaker with water until its ¾ full
Place it over the Bunsen flame on top of the tripod stand and wire gauze
Heat the water bath until near boiling before putting in the test tubes
Note: Remember to
have your goggles
on during heating!
Note: Be careful not to
touch the beaker when
putting in the test tubes!
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2. ENERGY LEVEL TEST
Put over the flame, combustion takes place on the substance as the oilinside the substance burns.
Heat is given out as combustion is an exothermic reaction.
By measuring the rise in temperature and comparing with results with
other substances, we can determine which substance has the highest
energy level.
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CHEMICALS AND APPARATUS..
Samples of peanut , tidbits and cereals Retort stand & clamp
Evaporating dish
10 cm³ measuring cylinder
Test tube
Thermometer
A pair of tongs
Bunsen burner, tripod stand, wire gauze
Safety goggles
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PROCEDURE..
1) Add 5 cm³ of distilled water into a test tube.
2) Clamp the test tube to a retort stand.
3) Measure and record the initial temperature of the water in the test tube.
4) Using the tongs, burn the peanut sample until it catches fire.
5) Place the burning peanut under the test tube in the evaporating dish (or
on the white tile) such that the flame is just in contact with the test tube.
(Note: If the flame goes out and the peanut is not completely burned,
relight the peanut .)
Note: Do not clamp thetest tube too tightly
else it will break!
Note: Remember to
have your goggles
on during heating!
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PROCEDURE..
6) Continue to burn the peanut until the remains could not be further
burnt.
7) Measure and record the highest temperature of the water reached.
8) Repeat steps 1 7 with samples of tidbits and cereals with comparable
mass .
Note: Keep the Bunsen flame
further from the test tube toreduce heat gained from
surroundings!
Note: Bulb of thermometershould not touch the test
tube when reading!
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THE RESULTS!
Benedicts Test Coke: Blue Orange
Coke zero: Blue Blue
What are we testing for?
High Fructose Corn Syrup
What gives the sweet taste of Coke zero?
Artificial sweeteners (aspartame)
Thus, coke zero is safe for diabetic patients consumption
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THE RESULTS!
Energy level test Change in temperature of tidbit set up > Change in temperature of
peanut set up > Change in temperature of cereal set up
Sources of error
Cannot be sure that all oil in the samples have been extracted out
Time lag between transferring from over the flame to below the test tube
heat loss to surroundings
How can the error be prevented/minimized?
Do several experiments to improve accuracy of results
Heat the samples right below the test tube (too dangerous for lab
experiments)