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II.2.4.2. Apply what you have learned

👀 Experiment: Determining the volume of a drop

Required materials:
Pipette, graduated cylinder.


Experiment description:

  • Pour water into the graduated cylinder with the pipette, counting the drops.
  • To find out the volume of a drop of water, divide the volume of water in the cylinder by the number of drops.

For example, I counted 10 drops for a volume of water of 0.5 cm3 (mL).

The volume of a drop is:



👀 Experiment: Determination of flow rate

Required materials:
Pipette (dropper bottle), graduated cylinder, timer.


Experiment description:

  • A certain volume of water is dripped into the graduated cylinder, measuring at the same time the duration of the drip.
  • To determine the flow rate (by volume) from the dropper, divide the volume of water in the graduated cylinder by the measured time.

I used two different droppers:

  1. At dropper 1 we collected a volume of water of 0.5 cm3 in 6 s.


  1. At dropper 2 we collected a volume of water of 0.5 cm3 in 6.88 s.
🔓 Solved problem

1. How many 10 L buckets of water can be filled in one year (365 days) from a faulty tap that flows a drop at every second? We consider the volume of a drop to be 0.05 ml.

Solution:

We calculate the volume of water collected from a drop with a volume of 0.05 mL in one year. Knowing that a year has 365 days, o day has 24 h and one hour has 3600 s, we get the volume of water:

Vwater = 365 ∙ 24 ∙ 3600 ∙ 0.05 mL = 1576800 mL = 1576.8 L.

We calculate the number of buckets with a volume of 10 L that can be filled with 1576.8 L of water:

No. buckets = 1576.8 L : 10 L = 157.68 filled buckets