The student conducted an experiment to test whether heavier coins would reach the bottom of a bottle faster than lighter coins. Four coins of different denominations were dropped from 70cm above a bottle filled with 800ml of water, and the time taken for each coin to reach the bottom was recorded. The heaviest coin, the Dubai coin, took the least average time of 0.855 seconds to fall, disproving the hypothesis that heavier coins would fall faster. The student concluded that coin weight did not impact falling time in water and suggested modifying variables like water amount or drop height for further experiments.

1. +
Coin’s Gravity
By Nancy 6A

2. +
Problem / Question
 Will the heaviest coin touch the bottom of the drinking bottle
faster?

3. +
Observation / Research
Gravity the force that attracts a body toward the center
of the earth, or toward any other physical body having
mass.

4. +
Hypothesis
 I think that the heaviest coin will need less time to touch the
bottom of the bottle because it will drift through water faster.

5. +
Independent Variable
 Kind of coin
 I’m going to use Dubai coin, Rp. 1,000 coin, Rp.500 coin and Rp.
200 coin.

6. +
Dependent Variable
 In this case, it will be the time the different kinds of coins will
touch the bottom of the bottle faster.

7. +
Control Variable
 The kind of bottle
 The amount of water
 The height from where the coin will be dropped from

8. +
Experiment

9. Materials Equipment
800 ml of water 4 different kinds of coin (Dubai
coin, Rp. 1,000 coin, Rp.500 coin
and Rp. 200 coin)
1 drinking bottle with wide opening
1 measuring cup
1 stopwatch
1 m ruler

10. +
 Measure 800 ml of water using the measuring cup
and pour it inside the water bottle after removing the
cover.
Steps / Procedure (1st)

11. +
Steps / Procedure (2nd)
 Place the 1 m ruler behind the bottle.

12. +
Steps / Procedure (3rd)
 Drop the different kinds of coins from 70 cm and count the time
using the stopwatch.

13. +
Steps / Procedure (4th)
 Record the data.

14. +
Kinds of Coins Trials (Time needed) Average
1st 2nd 3rd 4th
Dubai coin 0.95
sec
0.53
sec
1.35
sec
0.59
sec
0. 855 sec
Rp. 1,000 coin 0.56
sec
0.60
sec
0.61
sec
1.38
sec
0. 7875 sec
Rp.500 coin 0.65
sec
0.98
sec
0.91
sec
0.91
sec
0. 8625 sec
Rp. 200 coin. 1.20
sec
1.40
sec
0.98
sec
1.53
sec
1. 2775 sec

16. +
Conclusion
 So, my hypothesis is not proven because all the coins weigh
the same but the Rp. 1,000 coin needs least time to drift
through water faster (in average). Next time, if we do this
experiment again, we can modify it by changing the dependent
variable which is the different kinds of coins into different
amount of water or the height we will drop the coin from.