EXPERIMENT DIY PH indicator from red cabbage | What the Hack #22

Summary

In this fun and educational video, the host demonstrates how to create a homemade universal indicator using red cabbage to test the pH levels of common household solutions. Through a simple process of blending and straining cabbage, the resulting purple liquid changes color when exposed to acids and bases, helping viewers understand the concept of pH. The host tests various substances like lemon juice, vinegar, toothpaste, and bleach, showing how their pH levels vary. The video also explores how acids and bases can neutralize each other, providing a hands-on way to learn about chemistry.

Takeaways

• 😀 You can make your own pH indicator at home using red cabbage, which changes color depending on the acidity or alkalinity of a solution.
• 😀 Red cabbage juice acts as a universal indicator, changing color when it comes into contact with acids or bases.
• 😀 The pH scale ranges from 0 to 14, with lower numbers indicating acids, higher numbers indicating alkalines, and 7 being neutral.
• 😀 Common household substances like lemon juice, vinegar, toothpaste, and baking soda can be tested using the red cabbage indicator.
• 😀 Lemon juice is highly acidic, turning the cabbage juice bright red, while baking soda and water are alkaline, turning it blue-green.
• 😀 Water remains neutral and keeps the cabbage juice purple, indicating no acidity or alkalinity.
• 😀 Strong bases, like bleach, completely neutralize the cabbage juice color, turning it yellow.
• 😀 You can mix acidic and alkaline solutions to test if they neutralize each other and return the indicator to purple (neutral).
• 😀 Mixing lemon juice with bleach doesn’t neutralize the color, as bleach is a much stronger base than lemon juice is an acid.
• 😀 The reaction between vinegar and baking soda produces carbon dioxide but doesn’t fully neutralize the solution, leaving it slightly acidic (pink).
• 😀 Weak acids and bases, like lemon soda and toothpaste, can neutralize each other, turning the indicator back to purple.

Q & A

What is the purpose of the red cabbage in this experiment?

The red cabbage serves as a natural pH indicator. It changes color depending on whether it is exposed to acidic or alkaline solutions, making it useful for demonstrating the properties of acids and bases.

Why is the cabbage juice purple if it's called red cabbage?

Despite being called 'red cabbage,' the juice extracted from it appears purple. This is due to the anthocyanin pigments in the cabbage, which turn different colors when exposed to acids or bases.

How can you make your own pH indicator using red cabbage?

To make your own pH indicator, blend a few large leaves of red cabbage with water, then strain and filter the mixture to remove solid cabbage particles. The resulting liquid will serve as the pH indicator.

What is the pH scale, and how is it used in this experiment?

The pH scale measures the acidity or alkalinity of a solution, ranging from 0 to 14. Solutions with a pH below 7 are acidic, those above 7 are alkaline, and a pH of 7 is neutral. The red cabbage indicator changes color based on these pH values.

What happens when lemon juice is mixed with the cabbage indicator?

Lemon juice, being highly acidic, causes the cabbage indicator to turn a bright red color, indicating its low pH value.

How does the cabbage indicator respond to alkaline substances?

Alkaline substances, like toothpaste and baking soda, cause the cabbage indicator to turn shades of blue or green, depending on the strength of the base.

What does it mean when the cabbage indicator turns purple in the water?

When the cabbage indicator turns purple in water, it means the solution is neutral, with a pH close to 7. Water itself has a neutral pH.

What happens when you mix an acid like lemon juice with a base like bleach?

When you mix lemon juice (acid) with bleach (a strong base), the color does not change because bleach is a much stronger base, overpowering the acid. More acid is needed to neutralize the bleach completely and turn the color back to purple.

Why does the vinegar and baking soda mixture release gas?

When vinegar (an acid) is mixed with baking soda (a base), they undergo a chemical reaction that produces carbon dioxide gas, which causes bubbling and fizzing.

Can this experiment be done with other household substances?

Yes, you can try testing other household substances like soap, milk, or cleaning products. Each will produce different color changes in the cabbage indicator, helping you learn more about their pH levels.