ClassX Video Lessons Why doesn’t glue stick to the inside of the container? – Big Questions – (Ep. 29)
Hi there! Have you ever wondered why glue doesn’t stick to the inside of its bottle? It’s a question many people ask, and today, we’re going to explore the answer together. Let’s dive in and learn about the science behind glue!
There are different types of glue, but we’ll focus on the regular white craft glue, like the kind you might use for school projects. This type of glue is usually made from synthetic materials, which means it’s created in a lab rather than using animal parts like it was in the past.
White craft glue is water-based and contains special substances called polymers. Polymers are like long chains of molecules that repeat over and over. They are found in many things, including plastics, rubber, and, of course, glue!
One common polymer in white craft glue is called polyvinyl acetate, or PVA for short. PVA is great for glue because it dissolves in water, making it perfect for sticking things like paper and cloth together.
The secret to why glue doesn’t stick inside the bottle lies in its ingredients. As long as the glue stays inside the bottle and away from air, it remains liquid. This is because the glue is water-based, and it needs to lose water to harden. When you open the bottle and use the glue, the water starts to evaporate, causing the glue to dry and stick to surfaces.
Super glue is a bit different. It’s made from something called cyanoacrylates, which are very strong and fast-acting adhesives. Super glue needs a tiny bit of water to become sticky. It usually gets this water from the surface of the items you’re gluing. Inside the bottle, there’s no water, so it stays liquid. But if water gets inside, the glue will start to harden and stick to the bottle.
So, the next time you use glue, you’ll know why it doesn’t stick inside the bottle. It’s all about keeping the glue away from air and water until you’re ready to use it. Science is pretty cool, right?
If you have more questions about how things work, feel free to ask! There’s always something new to learn.
Try this experiment to see how glue dries! Take a small amount of white craft glue and spread it on a piece of paper. Leave it in a warm, dry place and check it every hour. Write down your observations about how the glue changes over time. What do you notice about the texture and stickiness?
Use pipe cleaners or string to create a model of a polymer chain. Twist and connect them to show how polymers are long chains of repeating molecules. This will help you understand the structure of the glue’s main ingredient, polyvinyl acetate (PVA).
Imagine you are an inventor! Design a new glue container that keeps the glue fresh and prevents it from drying out. Draw your design and explain how it works. Think about how you can keep air and water away from the glue inside the bottle.
Gather different types of glue, such as white craft glue, super glue, and a glue stick. Test them on different materials like paper, plastic, and fabric. Record which glue works best for each material and discuss why some glues are better for certain tasks.
Research how glue was made in the past compared to today. Create a timeline showing the evolution of glue from natural adhesives to synthetic ones. Share your findings with the class and discuss how technology has improved the way we make and use glue.
Sure! Here’s a sanitized version of the transcript:
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Hi, I’m Craig, and this is Mental Floss on YouTube. Today, I’m going to answer a big question that we get asked a lot around here: Why doesn’t the glue stick to the inside of the bottle? Thanks for that question, Joe, Spencer, Solomon, Rachel, Sarah, and many more of you. Let’s get started!
There are a few different types of glue, but I assume most of you are referring to regular white craft glue, so let’s stick with that for now. I’ll also tell you a little about super glue.
First, let’s talk about the composition of white craft glue. Nowadays, products like Elmer’s glue are usually synthetic rather than made from animal parts like they used to be. They are water-based and contain some synthetic polymers, which are substances that contain repeating molecular subunits. Polymers make up things like plastics, rubber, and glue. We don’t know exactly which polymers are used because brands like Elmer’s tend to keep their formulas secret.
One polymer that’s probably used in many white craft glues is polyvinyl acetate, also known as PVA. Since craft glue is typically water-based, it works well with PVA because it’s water-soluble, making it the perfect material to use as an adhesive for porous items like paper and cloth.
So, why doesn’t it stick to the bottle? Well, it has to do with those ingredients. According to the Elmer’s website, as long as the glue remains inside the bottle, away from air, it will remain fluid. Glue hardens when there is a loss of water from the formula. Exposure to the atmosphere causes the water to evaporate, which makes the glue harden.
Super glue, on the other hand, is made from cyanoacrylates, which are also adhesives but are more fast-acting and strong. In order to become sticky, super glue needs a small amount of water, which it can get from the surface of most items that people try to glue together. So, in a bottle of super glue, there should actually be no water, or else it risks drying out. If it comes into contact with water, it will stick to the bottle.
Thanks for watching Mental Floss on YouTube, which is made with the help of these wonderful folks. If you have a big question of your own that you’d like answered, please leave it below in the comments. I’ll see you next week!
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Let me know if you need any further modifications!
Glue – A sticky substance used to hold things together – In science class, we used glue to stick the pieces of our model together.
Bottle – A container with a narrow neck, used for storing liquids – We filled the bottle with water to use in our chemistry experiment.
Water – A clear liquid that is essential for most forms of life – Water is often used in experiments to dissolve substances and observe reactions.
Polymers – Large molecules made up of many repeating units – Plastic is made from polymers, which are long chains of molecules.
Molecules – Groups of atoms bonded together, representing the smallest unit of a chemical compound – Water molecules are made up of two hydrogen atoms and one oxygen atom.
Craft – An activity involving skill in making things by hand – In our science project, we crafted a volcano model to demonstrate an eruption.
Acetate – A type of plastic often used in sheets for transparency – We used acetate sheets to cover our science notes and keep them clean.
Ingredients – Substances that are combined to make a particular product – The ingredients for our slime included glue, water, and borax.
Air – The invisible mixture of gases that surrounds Earth and is necessary for breathing – We learned that air is made up of different gases, including oxygen and nitrogen.
Science – The study of the natural world through observation and experiment – Science helps us understand how the world works, from the smallest atoms to the largest galaxies.
