Science at Home | Bubble Membranes - Grade 12

Summary

In this educational video from the Ontario Science Centre, Ann and her children Sophia and Nathan explore the science behind bubble membranes. Using everyday materials like water, soap, and sugar, they demonstrate how to create bubbles and pass objects through the bubble membrane by explaining the chemical properties of soap molecules. The video draws parallels between bubble membranes and cell membranes, explaining how phospholipid bilayers control what enters and leaves a cell, similar to how soap bubbles behave. The activity includes tasks like creating a pore in the bubble membrane and making bubbles within bubbles.

Takeaways

• 🧪 Ann, along with her children Sophia and Nathan, demonstrates how to explore bubble membranes with a simple DIY experiment using household materials.
• 💧 The experiment involves creating a bubble solution with water, dish soap, and sugar, which can substitute for glycerin to stabilize bubbles.
• ✂️ To make the bubble contraption, straws are cut in half, and string is threaded through them to form a rectangle for making bubbles.
• 🎯 The experiment tasks include creating a bubble membrane, inserting objects through it, forming a pore with a loop of thread, and making a bubble within a bubble.
• 🧼 Soap is amphipathic, meaning it has a hydrophilic (water-attracting) head and hydrophobic (fat-attracting) tail, a crucial property for bubble formation.
• 🔬 The molecular structure of soap bubbles mirrors that of cell membranes, with hydrophilic heads pointing toward water and hydrophobic tails facing the air.
• 🖊️ Objects can pass through the bubble membrane if coated with soap, because the soap alters their surface to resemble the membrane’s chemical properties.
• 🌡️ Creating and removing a pore in the bubble membrane simulates how substances pass through cell membranes, which also have pores or channels.
• 🫧 The cell membrane, like a bubble, consists of a phospholipid bilayer that controls the flow of substances in and out of the cell.
• 🔍 Inside cells, there are smaller membrane-bound structures, or organelles, making the cell a 'bubble within a bubble,' just like in the bubble experiment.

Q & A

What ingredients are needed to create the bubble solution?

The ingredients needed for the bubble solution are 140 ml of water, 10 ml of dish soap, and 2 teaspoons of sugar. Glycerin can also be used if available.

How do you make the bubble contraption?

To make the bubble contraption, cut a straw in half and cut a piece of string about the length of your arm. Thread the string through the two pieces of straw, tie the string, cut off any excess, and tuck the knot into the straw to create a rectangular frame.

What are the five tasks to be done with the bubble membrane?

The five tasks are: 1) create a bubble membrane, 2) put an object through the bubble membrane, 3) create a pore in the membrane using a looped thread, 4) remove the pore and reform the membrane, and 5) use a straw to create a bubble within the bubble.

Why does a dry object pop the bubble membrane, but a soap-coated object does not?

A dry object pops the bubble membrane because it is not chemically similar to the membrane. However, when coated in soap, the object has the same chemical properties as the bubble, allowing it to pass through without popping it.

What is an amphipathic molecule, and how is soap related to this concept?

An amphipathic molecule has both hydrophilic (water-loving) heads and hydrophobic (water-repelling) tails. Soap is amphipathic, with its hydrophilic head attracted to water and its hydrophobic tail repelling water.

How is a bubble membrane similar to a cell membrane?

A bubble membrane is similar to a cell membrane because both consist of molecules that form two layers, with hydrophilic heads pointing towards water and hydrophobic tails pointing towards the air or inside the membrane. This structure forms a barrier that controls what enters and leaves.

What is a phospholipid bilayer, and what role does it play in the cell membrane?

The phospholipid bilayer is the structure of the cell membrane, composed of phospholipid molecules with hydrophilic heads and hydrophobic tails. It acts as a barrier that controls the movement of substances in and out of the cell.

Why can oxygen pass easily through the cell membrane while glucose cannot?

Oxygen is small and nonpolar, allowing it to pass easily through the cell membrane. Glucose, being larger and hydrophilic, cannot pass through the hydrophobic middle of the membrane and requires a pore or channel made of proteins to enter the cell.

What is the significance of creating a pore with a loop of thread in the bubble membrane experiment?

The creation of a pore with the looped thread demonstrates how pores or channels in cell membranes allow substances like glucose to pass through, mimicking the function of protein channels in biological membranes.

How is the 'bubble within a bubble' concept related to cell structure?

The 'bubble within a bubble' concept mirrors the structure of a cell, where the cell membrane forms an outer bubble and the organelles within the cell, like the nucleus and mitochondria, are surrounded by their own membranes, creating smaller bubbles inside the larger one.