(b) Four glasses are provided to you containing cold water, ice cubes, boiling water and normal water. If a balloon is fixed on the mouth of each glass which balloon will inflate?
Answers
Explanation:
Balloon in hot and cold water experiment
Hypothesis
The volume of air changes based on the temperature surrounding it.
Air expands or contracts based on increase or decrease in surrounding temperature.
Things you need to do Balloon Experiment
1) Two plastic/ glass container (bottles)
2) Balloons
3) Hot Water
4) Ice cubes as a cold water source
5) Containers to place hot and cold water
Preparation Steps
1) You can prepare your children or students by asking “How can you inflate the Balloon without touching it?”.
2) Note down their expected answers. But discuss their solutions only after performing the experiment to catch the science concepts behind it easily.
Step by Step Directions
Let’s start with the hot air experiment.
Step-1:
Take a glass container and add cold water. Then, add few ice cubes to it to keep it cold.
Step-2:
Pick another glass container and add some amount of hot water into it. Ensure the hot water’s hotness need not to be sizzling.
Step-3:
As step 3, bring our Balloon over the neck or mouth of the crystal clear plastic bottle in an upside-down position. And fix the mouth of the Balloon to the mouth of the bottle as shown in the picture.
Make sure the bottle is empty before you attach the Balloon to it.
Repeat the same method and prepare another set of water bottle and Balloon using the other empty bottle.
Step-4:
In this step, keep the ballon attached bottle inside the container, which consists of hot water. Let the bottle sit in hot water for some time.
You will observe the Balloon starts inflating itself without any external force. Amazing, isn’t it!?
Step-5:
And then bring the same and another set of water bottle into the container which consists of cold water. And allow it to sit for some time to see the results.
You will observe the Balloon starts shrinking itself by deflating the air inside it.
Note: If you feel the hot water is becoming cool, replace it with another hot water cup. In the same way, if you feel the cold water is becoming hot due to outside temperature impact, add some more ice cubes and make it cool. In this way, you can maintain the temperatures of the water while repeating the experiments.
Science Behind Expanding Balloon on Hot Water
The quantity of air occupied in a particular space, i.e., an open or closed container, denotes ‘Volume.’
Well, an empty water bottle is also populated with a certain amount of air molecules inside it—the air molecules inside and outside the bottle move with equal pressures at normal surrounding conditions.
In this activity, when we attach a balloon over the bottle’s mouth and place it in a hot water container, the Balloon starts inflating. It is because the hot air molecules enter into the Balloon from the bottle, which is in a hot water container.
These hot air molecules move faster inside the Balloon and occupy more space as they become less dense than usual. When they become less dense, it requires more space to settle, and that is why the Balloon starts inflating to provide more space for hot air molecules.
And when the Balloon inflates in hot water, bring it into the container containing cold water. Here, the cold air molecules replace the hot air molecules because hot air molecules cool down due to cold water.
When the air molecules become colder, air molecules’ density gets back to a denser state and requires less space to occupy. That is why the inflated Balloon deflates when the bottle is placed inside a cold water container.
This is how the volume of air calculated:
Volume= Mass x Density
Safety Tips
Have adult supervision at all times during the experiment to avoid any unforeseen incidents.
Suggested to wear gloves and safety glasses while doing experiments with hot water.
Avoid handling hot water by small kids.