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Notes for teachers

This lesson is an integration of ELA and STEM. The students will be introduced first to the reading of a short story as a springboard for the STEM lesson. They will answer comprehension questions and write a narrative of their personal experience performing the experiment.

For STEM, they will learn the concept of oxidation, chemical and physical reactions, They will conduct an experiment of writing and revealing invisible ink using the materials provided for them.

Before the class starts, gather all the needed materials

LIST OF MATERIALS

METHOD 1

Water
Bowl (1 per student)
Spoon (1 per student)
White paper (1 per student)
Cotton swab or paintbrush (1 per student)
Lemon (1/2 per student)
Heat source (hair dryer, lamp, candle)

METHOD 2

Water
Baking soda
Bowl (1 per student)
Spoon (1 per student)
White paper (1 per student)
Cotton swab or paintbrush (1 per student)
Turmeric and rubbing alcohol OR concentrated grape or blueberry juice. Note: Instead of rubbing alcohol another high percentage alcohol (40 percent or more) can be used. Water does work as well but the results won't be as intense

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Standards

Science and Engineering Practices

ask questions and define problem
develop and use models
plan and carry out investigations
analyze and interpret data
use mathematical and computational thinking
construct explanations and design solutions
engage in argument from evidence
obtain, evaluate and communicate information

Standards

Science

5.P1U1.2 Plan and carry out investigations to demonstrate that some substances combine to form new substances with different properties and others can be mixed without taking on new properties.

ELA

5.RL.1 Quote accurately from a text when explaining what the text says explicitly and when drawing inferences from the text.

5.W3 Write narratives to develop real time or imagined experiences or events using effective technique, descriptive details, and clear event sequences?

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Objectives:

The students will read a short story and answer the comprehension questions.

The students will learn scientific terms.

The students will demonstrate the effects of oxidation by writing a message in invisible ink made from lemon juice, baking soda, turmeric, alcohol and heat.

The students will investigate the mystery of heat, chemical and physical changes.

The students will write a narrative of their personal experience performing the experiment pretending to be a spy.

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Agenda

I will allow two class periods for this activity.

Short Story Reading and Comprehension Check

Unlocking of Scientific Terms

Trivia Time/ Video Presentation

Presentation of Experiment Protocols

Performing Experiments

Group Discussion and Demonstration

Writing Activity

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Intro/Driving Question/Opening

Does citric acid make invisible ink?

Does glucose/fructose/sucrose make invisible ink?

Does potassium chloride make invisible ink?

Is there something else in the lemon juice that makes invisible ink?

How can you write and reveal a secret message using chemistry?

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Hands-on Activity Instructions

Read Aloud!

Engage students in reading a short story and answering comprehension questions

Hook Me Up

Have the students watch a video about facts and history of invisible ink and unlock terms.

Presentation of Experiment Protocols

Present to the students the step-by-step procedures, materials needed, and safety precautions to be observed in performing the experiment.

Performing Experiments

Give each group the materials they need to perform and reveal the invisible ink. Then, lead the students to perform the experiment and have them record their observations and answer to the focus questions in their Science Investigatory notebook.

METHOD 1

Squish and squeeze some lemon juice into the bowl and include a few drops of water.
Stir the water and lemon juice using the spoon
Dip a Q-tip into the lemon juice-water solution.
Use the damp Q-tip to draw a letter, symbol, or write a secret message on the white cardstock paper. Re-wet your Q-tip if necessary. Be careful to not soak the paper too much.

Let the paper dry completely.

How does the paper look after you have written on it? Can you see your message?

Can you still see the message when the paper has dried completely?

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Hands-on Activity Instructions

Continuation._

Use a heat source to heat up the paper.

What happens when you apply heat to the paper?

Why does this happen?

METHOD 2

Dip a Q-tip into the baking soda solution from your second cup.

Use the damp Q-tip to draw a letter, symbol, or write a secret message on the white cardstock paper. Re-wet your Q-tip if necessary. Be careful to not soak the paper too much.

Let the paper dry completely. If you see baking soda residues on the paper, remove it with a paper towel.

Dip a Q-tip or brush into the prepared turmeric solution. Paint the whole paper with the turmeric solution being sure to cover the secret letters you wrote with your baking soda Q-tip.

Focus Group Discussion

Why is heat important with this experiment?
What materials could you use instead other than q-tips?
Why are lemons so important in this experiment?
What would you predict would happen if we used a different fruit? (for example a grape fruit)

Wrapping Up

Have the students write a narrative of their personal experience performing the experiment and the usefulness of this experiment in people’s life.. Direct students that they should follow the effective technique, describe details, and clearly sequences the events in writing their narratives.

How does the paper look after you have written on it? Can you see your message?

How does the paper look when it has completely dried?

What do you notice? Can you explain your results?

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Assessment

The students list down the new ideas they learn or their takeaway from the lesson.

The students identify the factors that they observed that affected the making and revelation of invisible ink.

Completed secret messages

Completed written narrative

3-2-1 Exit Ticket

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Differentiation

A video of a step by step instructions in performing the invisible ink experiment can be provided for students who are having difficulties using the printed instruction guide.

Remediation

Extension/Enrichment

Have the students construct an argument using evidence on whether the process in performing invisible ink chemical or physical change?

Describe the connection between a series of historical events, scientific ideas or concepts, or steps in technical procedures. When was invisible ink used in history?

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