Title: “Leakproof Bag Challenge: Defying Gravity!”
Description: In this fun science experiment, you will learn how to make a leakproof bag using a few simple materials. You will explore the scientific principles of air pressure and the properties of polymers as you create a bag that can hold water without leaking. Get ready to test your engineering skills and see if you can defy gravity with your leakproof bag!
Scientific Principles:
- Air Pressure: The experiment will demonstrate how air pressure can be used to create a barrier against leaks.
- Properties of Polymers: You will learn about the unique properties of polymers and how they can be used to make a waterproof seal.
Equipment Needed:
- Ziplock bag (quart-sized or gallon-sized)
- Water
- Sharp pencil or skewer
- Towel or paper towels
Difficulty Ratings: Equipment Availability: 1/5 (Easy to obtain)
Experiment Difficulty: 2/5
Instructions
Step 1: Prepare the Materials
- Ask an adult to help you gather all the materials needed for the experiment: a ziplock bag, water, a sharp pencil or skewer, and a towel or paper towels to catch any potential leaks.
- Find a flat surface, such as a table or countertop, where you can work.
Step 2: Fill the Ziplock Bag with Water
- Open the ziplock bag carefully and hold it with one hand.
- With the help of an adult, pour water into the bag, but be careful not to overfill it.
- Leave a little bit of space at the top of the bag so that air can get inside.
Step 3: Remove Excess Air and Seal the Bag
- While holding the bag upright, use your other hand to gently press the sides of the bag to remove any extra air.
- Don’t press too hard or squeeze the water out of the bag.
- Once you have removed most of the air, ask an adult to help you seal the bag tightly by pressing the ziplock seal together.
Step 4: Prepare for the Experiment
- Place the sealed bag on top of the towel or paper towels on the flat surface.
- Make sure you have a sharp pencil or skewer ready for the next step.
Step 5: Test the Leakproof Bag
- Take the sharp pencil or skewer in one hand, near the tip, and be careful not to poke yourself.
- Choose one side of the bag to start. Gently press the tip of the pencil or skewer through one side of the bag, slowly and steadily.
- Keep pushing the pencil or skewer until it comes out the other side of the bag.
- Look closely at the bag and see if any water is coming out of the hole you made.
- If the bag doesn’t leak and the water stays inside, you have successfully created a leakproof bag!
Step 6: Clean up
- Remove the pencil or skewer from the bag carefully.
- Pour the water out of the bag into a sink or container.
- Use a towel or paper towels to dry the bag and the surrounding area.
Note: It’s essential to supervise children during the experiment, especially when handling sharp objects.
Simple Explanation:
When we seal the bag and poke a hole in it with the pencil or skewer, something interesting happens. The bag is made of a special material called a polymer, which is like a bunch of tiny chains stuck together. These chains are really good at sticking together and keeping things inside the bag. When we poke the pencil through the bag, the chains of the polymer stretch and close up around the pencil, making a tight seal. This seal stops the water from leaking out, even though there’s a hole in the bag!
Detailed Explanation:
The leakproof bag experiment demonstrates the principles of air pressure and the properties of polymers. The bag itself is made of a polymer, which is a long chain of molecules bonded together. Polymers have unique properties, including the ability to stretch and form a seal. When we fill the bag with water and remove the excess air, the air pressure inside the bag pushes against the bag’s walls evenly, creating a balance of forces.
When we poke the sharp pencil or skewer through one side of the bag, the polymer chains get stretched apart. However, the other chains surrounding the hole quickly come together to seal it. This happens because the polymer chains want to return to their original shape and bond with each other tightly. The result is a temporary seal around the pencil, preventing the water from escaping.
The seal works because the pressure from the water inside the bag pushes outward, while the tight polymer chains push inward. This balance of forces keeps the water inside the bag and prevents leaks. It’s an example of how materials like polymers can be engineered to create barriers against leaks and demonstrate the fascinating interplay between air pressure and polymer properties.
