Gloria’s Goggle Goof-up

Introduction

It is sometimes a challenge to get students to wear their goggles. Using a simple magic device called a penetration frame; dramatically illustrate the importance of wearing safety goggles and the consequences for not wearing them properly. “Gloria’s Goggle Goof-up” is a great way to introduce a serious safety concept to your students with the help of a little magic. Students will be amazed to see that their teacher can perform magic, and will never forget the lesson they just learned about the importance of wearing goggles properly in the science classroom and laboratory. This is a beginner’s level magic trick that requires only about five minutes to learn. Practicing the procedure well before your performance will ensure that the “magic” behind the penetration frame is not revealed.

Concepts

• Goggle safety
• Observation
• Discrepant event

Background

The penetration frame consists of a plastic frame with a clear glass (plastic) pane. The glass pane has a hole in it that is hidden or revealed simply by sliding the pane up and down. The hole is hidden under a thin strip of plastic that runs down the middle of the frame. The frame is in the locked position when the hole is hidden and no student card is in place on the side of the frame with the patent number inscription. A small lock is released when a student card is placed between the glass pane and the thin strip on the side of the frame with the patent number inscription.

Materials

Safety Precautions

The materials in this kit are considered nonhazardous. Please use normal laboratory safety precautions.

Disposal

The penetration frame may be reused and should be stored for future demonstrations. The student cards may be disposed of in the trash.

Prelab Preparation

1. Copy the student card page onto card stock paper.
2. Cut out two student cards for each demonstration.
3. Check that the hole in the penetration frame is not visible—frame should be in the locked position.

Procedure

1. Show students the penetration frame with the solid pane.
2. Pass the frame around for inspection to show students that it is solid.
3. Borrow a pencil or use some other object, such as a nail or dowel rod, that is smaller than the hole in the glass pane, to use as a penetrating object.
4. Tap on the glass pane with the penetrating object—use the following patter:

   The pane of glass in this frame represents the lens in your safety goggles. Your eyes are protected if you wear your safety goggles properly.

5. Show the students the student cards and continue the patter:

   This student is wearing safety goggles, however, the goggles are not being worn properly. It is very important to wear goggles properly to protect your eyes in lab. Wearing goggles around your neck, covering the back of your head, as an arm band or on top of your head like this student, is not the correct way to wear your goggles. Goggles can only protect the area they cover and are designed to cover your eyes.

6. Place one student card between the glass pane and plastic circle on the side of the frame with the patent number inscription. The student’s eyes should be centered in the circle (see Figure 1). Note: Placing the card on the side of the frame with patent number inscription will release the lock and allow the pane to slide freely.
   {13301_Procedure_Figure_1}
7. Turn the frame over and insert the second student card on the other side of the frame. As the student card is inserted, slide the glass pane away from the patent number inscription. This will center the hole so that it is in the middle of the circle in the frame.
8. Now that the cards are in place and the hole is centered in the plastic circle, continue the patter:

   If this pencil (or other penetrating object) were to become a projectile during an experiment and hit a student’s goggles, it would bounce off. However, since this student is not wearing goggles properly, there would be nothing to protect the student’s eyes and the flying pencil would damage the student’s eyes permanently.

9. Push the pencil or other penetrating object through the center of the plastic circle. The pencil should penetrate both student cards.
10. Show both sides of the frame to the students so they can see that the pencil really did penetrate both cards.
11. Remove the pencil.
12. Remove the card on the side of the frame with the patent number inscription. As the student card is removed, slide the glass pane toward the patent number inscription. This will hide the hole in glass pane behind the thin plastic strip in the middle of the frame. Note: When the card is removed the pane will lock in place automatically.
13. Remove the other student card.
14. Pass the frame around for inspection again to show the students that the glass pane is, indeed solid. Note: Do not allow students to pry on the thin plastic strip because it will break.
15. Pass the student cards around for inspection to show the students that the pencil truly did penetrate both cards.
16. As the students examine the cards and the frame, continue the patter:

    The lens in your safety goggles is solid like the glass pane in this frame. I tapped on it and the pencil would not go through; however, this is only effective if safety goggles are worn correctly. As you just witnessed, the goggles did not protect the student’s eyes when worn on top of the head. This student had to learn the lesson the hard way and will never be able to see again. Make it a point to wear your safety goggles properly—if you don’t they will not protect you. Goggles are required during every experiment and specifically when using heat, glassware, or chemicals, or when there is a possibility of projectiles resulting from an experiment. I hope you will remember to wear your safety goggles properly during every experiment in this class and at any time when asked.

17. Collect the penetration frame for the next safety demonstration or for storage.

Student Worksheet PDF

13301_Teacher1.pdf

Teacher Tips

• Be careful not to place your hand or other body part in front of the hole in the penetration frame when you push the pencil through.
• Use a pencil borrowed from a student, small dowel rod or nail. The device you use to penetrate the frame must be smaller than the hole in the glass pane to ensure that it will penetrate the cards.
• Do not force the pencil too hard—it should push through the card with a moderate amount of force.
• One card may be placed in the frame instead of two, however, it must be placed on the side of the frame with the patent number inscription and the back of the frame may not be shown to students or they will see the hole in the glass pane.
• Students should not try to pull on the plastic strip and circle in the center of the frame because it will break.
• Using too much force or stress will crack the glass pane. Do not tap on the glass pane too hard.