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The Group 4 projectGroup 4

Noor, Haakon, Shazeb, Jim and

Lisa

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ContentsChemistryBiology Physics

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Chemistry

How does surface area and temperature affect the rate of evaporation of salty water and tap water?

Hypothesis

Factors that determine how fast a liquid will evaporate:

High temperature

Large surface area

Water has a faster rate of evaporation than salty water

Materials

100 ml beaker

250 ml beaker

1000 ml beaker

Syringe 10ml

Thermometer

Bunsen burner

Tripod stand with gauze

Heat proof mat

Tap water

Salt water

Timer

Glass rod

Weighing balance

Method

Add 55ml of water/ salt water to 100ml beaker and heat it for 10 minutes at the boiling point i.e. 100°C.

Record the mass of water/ salt water after 10 minutes.

Repeat the same steps for 250ml and 1000ml beaker with the temperature of 100°C.

Repeat the same procedure for 3 different surface areas at the temperature of 90°C and record the mass of water/ salt water after 10 minutes.

Results

Tap water Volume before heating (ml)/±0.5ml

Volume after heating for 10 minutes (ml)/±0.5ml

Beaker 100 ml 55.0 28.0

Beaker 250 ml 55.0 4.0

Beaker 1000 ml 55.0 0 (completely evaporated at 7:31)

Salt water Volume before heating (ml)

Volume after heating for 10 minutes (ml)

Beaker 100 ml 55.0 17.0

Beaker 250 ml 55.0 17.5

Beaker 1000 ml 55.0 21.0 (the water was completely evaporated at 10:00)

For 100°C:

Results

Tap water Volume before heating (ml)/±0.5ml

Volume after heating for 10 minutes (ml)/±0.5ml

Beaker 100 ml 55.0 49.2

Beaker 250 ml 55.0 41.8

Beaker 1000 ml 55.0 21.7

Salt water Volume before heating (ml)

Volume after heating for 10 minutes (ml)

Beaker 100 ml 55.0 48.7

Beaker 250 ml 55.0 49.8

Beaker 1000 ml 55.0 51.5

For 90°C

Conclusion

Rate of evaporation is the fastest for tap water in 1000ml beaker at 100°C.

Salt water evaporates at a higher temperature than tap water – due to the intermolecular forces between the water molecules and the salt dissolved in it.

the rate of evaporation for salt water in 1000ml beaker at 90°C weighed more than the 100ml and 250ml beaker – against our hypothesis!

Evaluation

Amount of heat/flame of the bunsen burner was not equal for each of the experiment carried out.

An electronic heating system could have been used so that the level of heat provided is the same for each experiment.

The electronic balance with an uncertainty of ±0.001g could have been used for a precised mass of salt added to make the salt solution.

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Biology

Does caffeine and sugar have a strong impact on race times in comparison to water?

Hypothesis

Providing the test subjects with 1 l of Cola will make them run faster than when provided with 1 l of

water.

Step 1: test subjects

Step 2: hydration

Step 3: running

Results

Time w/ Cola

Time w/ Water

1 87 93

2 87 97

3 88 95

Average 87.3 95

Evaluation and Conclusion

We saw that the time for the test subjects to run 400m decreased when given water instead of coke.

There are many variables that were not taken into account.

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Physics How does the amount of mass added affect the

range a water rocket flies?

1. Build a Rocket

Theory behind the bottle rocket

When pumped, the air inside the bottle will be compressed.

Eventually the pressure will be too high for the cork in the bottle to withstand, thus creating thrust..

Hypothetically, when we add mass the initial velocity will change, causing a shorter distance to be travelled

2. Procedure

Fill with 0.6 l of water

Push in cork

Push in nozzle

Pump

Repeat three times for each mass added

Record results for eight different masses

3. Firing the rocket

Results

Weight Added (g) ±1g

Trial 1 ± 1m

Trial 2 ± 1m

Trial 3 ± 1m

Average (m)

0 28 26 27 27

100 25 26 24 25

200 20 20 21 20

300 17 18 19 18

400 16 15 16 16

500 10 12 14 12

600 9 11 9 10

700 7 7 8 7

Observations

As mass was added, range decreased.

Evaluation

We attempted to keep several factors constant:Angle of ramp (40°)Rocket designAmount of water in the rocketWeather conditions

However, the rocket didn’t always fly straight. The pressure needed to dislodge the cork is likely to have varied.

Evaluation cont.

In our experiment, the initial velocity decreased as a result of the added mass. Thus the one variable became two variables.

This yielded a shorter range.

There is theoretically (according to v = u + at) no change in the range if initial velocity is kept constant.

Conclusion

Range decreased with amount of mass added

This is a result of decreasing initial velocity due to added mass, meaning our experiment was not a fair test.

Group Members:

Noor Haakon ShazebJim Lisa