Script: Welcome to the Ingenia Chemistry Lab. We are happy to have you here for your orientation as chemistry apprentices. You will be working on our newest project. We are developing a new product (pause for effect), invisible ink! Our product will allow people from all over the world, from children to government officials, to send secret messages. Are you ready for this challenge?
Before we get started, we need to talk about safety in the lab. You will need some special equipment in order to be safe in the lab. (Have a box or a paper bag with one set of safety equipment inside and show it to students) What do you think is inside this bag? (allow students to make some guesses.) Let’s find out.
First we have an apron. Why do you think it is important to wear this apron? (possible answers: to protect our clothes)
Next we have disposable gloves: why do you think it is important to wear gloves in the chemistry lab? (possible answers: to protect our skin). Yes, it is very important that you don’t touch chemicals because you don’t know how they might react on your skin.
Finally, we have safety goggles. Why do you think it is important to wear safety goggles? (possible answers: to protect our eyes) Yes. It is very important to be safe in the chemistry lab.
Please remember that when you work in a chemistry lab it is important to follow directions and to avoid touching, smelling or tasting any chemicals. (Give students their safety gear)
Now let me show you a magic trick, or should I call it a chemistry trick?
A Colorful Magic Trick with Acids and Bases (https://www.tdwscience.com/) (show only the first 1:21 minutes)
Script:
The magic/chemistry trick you saw has to do with pH, acids and bases. But what is pH? What is an acid? What is a base? Let’s watch a video:
PH Scale - BrainPop UK © 1999–2023 BrainPOP. All rights reserved.
Today you will experiment to find out if some solutions are acids or bases. You will use something called an indicator. An indicator is a substance that changes colors in the presence of an acid or a base. Some indicators only change for bases, some indicators only change for acids and some indicators change for both. The indicators you will use today are grape juice, turmeric and ph paper.
Note to teacher: Students can use the following chart to record their observations. PH Experiment Chart
Discuss the results of the experiment with students. Have the different groups share their results and talk about the patterns you observe. Ask students what they learned from this activity.
Ask students: How can we use the change of color caused by an indicator to create invisible ink? See if they come up with some ideas of using a clear liquid like the baking soda solution to write a message and use the grape juice as the developer that reveals the message or writing the message with lemon juice or vinegar and using a turmeric solution as a developer to reveal the message.
You can show the following videos or have students watch these videos for some ideas.
Pop! Bang! Fizz! Invisible Ink! (www.scpld.org)
Make Your Own Secret Ink! (www.youtube.com/@SciShowKids)
Science Buddies: Invisible Ink (https://www.sciencebuddies.org/)
Script: Now it’s your turn to create secret messages using chemistry. Follow the directions to make and reveal your secret message
Script: Engage students in discussion about activity.
Script: Why is it important to know the pH of a substance? Let’s watch a video to learn more about the importance of pH in our everyday lives:
pH in Everyday Life | Acid Bases and Salts (infinitylearn.com)
Tell students they are going to meet a chemist and learn about her job. Show the following video:
Chemistry careers - A day in the work life of a chemist (https://www.careers.govt.nz/)
After watching the video, discuss the following questions with students:
Review the following vocabulary with students. Prepare some index cards half the cards should have the vocabulary and half the cards should have the definition. Pass the cards to students and have them mingle around the room and find the person that has the matching vocabulary/definition.
Base: a chemical substance with a pH higher than 7, it is a slippery solution on water, it tastes bitter.
Acid: a chemical substance with a pH lower than 7, it tastes sour, it can react with metals Indicator: a substance that changes color in an acid or in a basic solution
pH: It is the measure of how acidic or basic a substance is.
Tell students to prepare a secret message on a piece of paper and to pack some developer in a small cup with a lid to take home and present it to their family.
