Are you aware of magic water bottle? We are going to perform a very simple ‘Drip Drop Water Bottle Pressure Experiment’, which helps us to make the ‘Magic Water Bottle’.
This science activity helps us to experience the magical properties of air pressure and force.
What Exactly Happens in the Drip Drop Bottle Experiment
Objective: To create magic bottle and learn about the basic properties of Air-Pressure, Vacuum, Force, etc.
Time Required: Just takes 5 minutes-10 minutes
Safety Measures: As we are not using any toxic supplies or chemicals, the experiment is completely safe to investigate with children. But just be careful while drilling the hole on the bottle.
- An emptied plastic water bottle with a tight fitted cap (You can use either 2 litre or 1 litre water bottle)
- Food Coloring (we chose to use blue color)
- A glass jar
- A big enough glass Bowl or Pan
- Soldering Iron tool (In order to make holes)
Steps to Perform
Have a look at the simple step-by-step instructions in detail.
Step-1: Pick up a water bottle and Clean
Pick a regular plastic water bottle of your choice and clean it thoroughly. If you are using the new one, then please empty the bottle, before you start the experiment.
Make sure the bottle using for experiment is transparent, clean and tightly fitted by its cap. In this experiment, we chose 2 litre water bottle.
Step-2: Put a hole to the Bottle
Use a soldering iron or a simple nail to put a small hole just an inch above the base of the bottle using it.
I recommend parents or guardians to help your children during this step.
Take extra care while making a hole.
As the plastic is profuse, it is a good idea to push the pointed end of soldering iron thoroughly and slowly. You can even use a hammer to tap and push more easily.
Step-3: Mix food coloring to the water
Take required amount of water in a glass jar and mix a little amount of food color to the water taken.
Now, you are ready with color water. Why color water? Because, using color water makes it easier for the children to observe the magical outcomes of the experiment.
Even the purpose of using the glass jars is also for the same reason.
Step-4: Fill the bottle with Color Water
Cover the hole of the bottle using a tape or just simply using fingers. Now place the bottle in a wide mouthed glass pan or bowl in a standing position. Then, pour the color water into the bottle until the top line.
Step-5: Now release the covered Hole
Once you fill the bottle with color water, just take off the fingers or tape on the hole. And observe what happens.
Obviously, water starts leaking from the hole. Here is our magic trick lies.
Now take the bottle cap and tighten it to its brim of the bottle. Amazingly, the leakage of water from the hole at the bottom stops.
Step-6: Try to keep Multiple Holes to the bottle
To extend the activity, make multiple holes to the bottle about an inch height above the base level.
And then try the same steps 4 & 5 and observe the results. Even the multiple punctured bottle stops the leaking water through the holes when the bottle is tightened with its cap.
If you loosen the cap, the water starts leaking again.
Believe me, it would be a great water play for children while learning science concepts in a fun way.
As a Prank
Before you start the experiment, write in big letters on the bottle saying ‘Do Not Open the Bottle’. And then keep it aside on the table where kids play.
Generally, kids are naturally curious to do things which are not supposed to do or warned not to do.
So, kids who are passing by, one or another wish to open and learn why it should not be opened.
Then, as soon as the person open the cap of the bottle the water starts coming out through the hole and makes the person wet.
This is how we can use this simple science activity as a prank.
So, let us learn the science involved in this fascinating science activity.
Questions to Ask Children During and After the Experiment
Asking questions is the best way to improve child’s concentration and they even show much interest while performing experiments.
Here we go the questions that we can ask during and after this experiment.
Q.1: Why does the water stop leaking when you cover the hole with tape or thumb finger?
Q.2: What is the reason behind the bottle cap stopping the water leakage?
Q.3: Does gravity have any role in leaking the water through the hole?
Q.4: Does gravity shows any impact on stopping the water leakage?
Q.5: Are there any other forces acting on the water to push it out of the bottle through the hole?
Q.6: What is the role of air and its pressure during the experiment?
Q.7: Is the bottle actually unoccupied?
First, let your children guess and report their own answers. Later check whether they guessed correctly or not.
If your child is not correct, tell him/her the science behind it and get them scientifically knowledgeable.
Science behind the Drip Drop Experiment
As soon as the water inside the bottle is let go out of it, the air molecules occupy the vacuum inside the bottle.
We cannot see the air molecules occupying the vacuum of the bottle because air is invisible.
Hence, this proves that bottle is not vacant even though there is nothing inside. When the bottle is poured with color water, the water molecules pushes the air molecules out of the bottle through its mouth.
This is explained in detail through Avogadro’s law. Modern Avogadro’s law states that “equivalent number of gas molecules occupy the equivalent number of other molecules under equivalent temperature and pressure situations”.
In simple words, according to earlier Avogadro’s law: a gas law that establishes the relation between capacity (volume) and the quantity of gas.
Finally, it states that at constant temperature and pressure conditions, the volume of the gas is directly proportional to the quantity of the gas.
Coming to the experiment, when there is puncture on the bottle, the high pressured water flows outside, where there is less pressure.
And when the puncture and water filled bottle is tightened using a cap, there develops an equal pressure inside and outside the bottle. The presence of air pressure inside and outside the bottle stops the water leakage through the hole.
Thus, holding the water leakage magically. Eventually, when the cap is loosened, there is difference in air pressures built inside and outside the bottle.
And hence, the water inside the bottle where high pressure is present flows outside where there is low pressure. The high pressure inside the bottle is due to the water weight.
Extend the Experiment Further
1) Try to take two bottles and gives different number of holes on each bottle. And then check whether there is same result with both the bottles.
2) Make bigger size holes and check the results.
3) Make holes at different areas on the bottle and observe the changes if any.
The water filled plastic bottle with two holes at different heights leak water in two different ways. That means, the hole at the lowest point experience high pressure and leak water at high pressure. Whereas the hole on the plastic bottle at highest point experience low pressure and leak water at low pressure.
The flow velocity of water leakage varies absolutely on the size of the hole. If the size of the hole is smaller, it leaks water slowly and is time-consuming to leak out all the water from the bottle. While the large sized hole leaks out water quickly with high energy.
Ice has a special property of expanding when it gets freeze. The same thing we can see when we freeze the well stoppered bottle full of water if left in a deep freezer overnight. Because as the bottle is full of liquid and when this liquid gets freeze, the ice formation happens. The ice formed expands while freezing and pushes the stopper outside forcefully or else break the bottle.
The empty bottle when kept in the freezer starts slowly disintegrating until the temperature conditions inside the bottle is same as the neighbouring air temperature conditions.
The force of expanding ice while freezing is tougher than any other forces. So, when you freeze water bottles, the plastic bottles release various chemical substances which may cause cancer risk eventually. On the other hand, if you fill the bottle completely up to the brim, the water exerts stronger force while freezing and breaks the bottle inside the freezer.