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Chemical Magic    Mystery 3

Mystery 3 image

In this Mystery, students are introduced to acids, a group of substances with a reputation for being reactive. In the activity, students develop their own test for acids, then apply it to several common household substances in order to identify which contain acids.

THIS LESSON WAS REVISED ON JANUARY 11, 2018. If you've prepped prior to that date, we suggest using the previous version.

What would happen if you drank a glass of acid?

Beginning Exploration (1 of 4)
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Beginning Exploration (2 of 4)

DISCUSS:

This probably isn’t the first time you’ve heard the word ‘acid’. What does this word make you think of?

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Beginning Exploration (3 of 4)
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Beginning Activity Prep
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Activity: Acid Test
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Beginning Exploration (4 of 4)
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Beginning Complete!

You've completed the Exploration & Activity!

If you have more time, view the assessment, reading and extension activity in the optional extras.

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Optional Extras

Below are ideas for extending this topic beyond the activity & exploration which you just completed.
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Readings

These readings will get students thinking about how acids help shape the world around us. Free with registration on ReadWorks, a nonprofit committed to providing teachers with research-proven, Common-Core-aligned readings.

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Activity: Color-changing foods

Pigments in purple cabbage and black beans change color in acid. This list from Thought.Co. suggests other natural color-changing pigments to experiment with.

Here are three of our favorites:

  • Blueberries — The juice turns red when you add acid.
  • Grape juice — Manufacturers add citric acid to bottled grape juice, making the purple juice red. Adding baking soda makes the juice less acidic, making it fizz and change color.
  • Turmeric — Mix this yellow spice with water. Add baking soda and it will change color. (A word of warning: turmeric can stain hands and clothing.)
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Activity: Make an Egg without a Shell

This is one of our favorite activities. You start with an ordinary chicken egg. Leave it in vinegar overnight & the acid dissolves the eggshell. You end up with a egg that’s held together by the flexible membrane inside the shell.

You’ll find detailed instructions on how to make a “naked egg” on the Exploratorium’s Science of Cooking website.

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Activities: Taste the fizz

You’ve seen that adding baking soda to acid makes it fizz. Here are two activities that use that fizz to make tasty treats.

New Zealand’s Science Kids explain you how to make fizzy lemonade.

The folks at Planet Science explain how to make a candy treat called sherbet. Watch out! This candy zaps your tongue with fizz.

Who knew science could be so tasty?

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