Section 7.9

Learning Goals

• DAT-1.A.9: Students will describe how the use of digital data to approximate real-world analog data is an abstraction. 

• DAT-1.A.10: Students will define sampling technique. 

• Students will demonstrate the difference between analog and digital data.

• Students will compare and contrast analog and digital data. 

• Students will explain how digital methods are better than analog methods for storing, copying, and transmitting information. 

• DAT-1.A.8: Analog data have values that change smoothly, rather than in discrete intervals, over time. Some examples of analog data include pitch and volume of music, colors of a painting, or position of a sprinter during a race.   

• DAT-1.A.9: The use of digital data to approximate real-world analog data is an example of abstraction. 

• DAT-1.A.10: Analog data can be closely approximated digitally using a sampling technique, which means measuring values of the analog signal at regular intervals called samples. The samples are measured to figure out the exact bits required to store each sample. 

Objectives and General Description

Data that is stored on a computing device as a group of 1's and 0's is called digital data.  Analog data has values that change smoothly over time whereas digital data is stored in discrete intervals.  In this section, students will compare and contrast analog and digital data.  They will describe the advantages of digital and will explore examples of both analog and digital formats.  The students will begin by participating in a drawing activity from ScienceBuddies.com that will illustrate the differences in the two types of data.  Students will do further research on both analog and digital data as well as how to convert analog to digital.  Finally, students will use a game format to identify examples of both.

Activities

Activity 7.9.1 (budget 15 minutes)

1. This activity is adapted from  ScienceBuddies.com Analog Vs. Digital activity, the engage portion of the lesson.

2. Give each student a sheet of printer paper.  Have them fold and cut into 8 equally sized rectangles.

3. Arrange students into groups of 4 - 8 students each.

4. Tell each student to make a simple drawing (a shape, a smiley face, a stick figure, a letter, etc.) on one piece of printer paper.

   1. The drawing should only include lines (no shading) and they should be able to finish it in less than 30 seconds. 

   2. Everyone should write his or her name and the number "1" in the corner of the drawing.

5. Each student should pass his or her drawing to the next person in the group.

6. The next person should make a copy of the drawing by tracing it onto a new piece of printer paper. Write the number "2" and the original student's name in the corner of the paper.

7. Pass the copy (not the original) on to the next student, who will make another copy and number it accordingly. Repeat this process until there are eight versions of each drawing (the original plus seven copies labeled 2–8).

8. Return all copies of each drawing to the original student. Have students arrange their copies in order.

9. Discussion:  What do you notice about each subsequent copy of your drawing? Compare the last drawing to the initial drawing—how different are they?

10. There will be slight differences in the drawings but the shapes should be recognizable.  

11. Give each student a piece of graph paper and have them cut it into 8 equal rectangles.

12. Repeat steps 4 - 8 using the graph paper.  However, when "drawing" this time, each student should fill in the square, not just draw a line.

13. Discussion:  What do you notice about the drawings of your shape this time?  How does the last drawing compare to the first drawing?

14. The second method is better because each copy of the drawing is identical. It is very difficult to "accidentally" change a filled-in square to a blank square or vice versa when tracing on graph paper. However, when tracing on printer paper, your pencil tip can move continuously, resulting in small errors that accumulate with each new copy.

15. Explain that the first method the students tried was analog, meaning the positions of their pencils could vary continuously. The second method they tried was digital, meaning there were a fixed number of squares they could fill in on the paper. Since the invention of modern electronic communication (telephone, radio, television, internet, etc.), we have used both analog and digital methods to send information as signals, or a way to send information from one place to another. Electronic signals are usually sent through wires (like the cables connecting a computer to a monitor, or a game console to a TV) or wirelessly through the air (like the internet connection to a smartphone or tablet). Whenever you push a button on a game controller, download a song, or send a text message, you are using electronic signals. In the rest of the lesson, they will use an app on a phone to compare sending digital and analog signals across the classroom.

16. If you have the time and the android equipment, you can continue with Science Buddies next activity which is using a Google Science  Journal App to create signals.

Activity 7.9.2 (budget 20 minutes)

1. Give students time to research analog vs digital data.  Students should complete the Analog vs Digital Data Guided Notes for the two websites mentioned on the handout.  

2. Analog vs Digital Data Guided Notes KEY

Activity 7.9.3 (budget 10 minutes)

Chose a game format to help students identify analog or digital devices.

1. Make a matching game for analog vs digital.  Students use magazine/newspaper pictures and create a matching game.

2. Great set of online games https://www.legendsoflearning.com/learning-objectives/digital-signals/ 

3. Let students play some of the online games and then have them create their own online game in Scratch, Snap! or AppInventor.

4. Search for a Kahoot that covers digital and analog.  There are a lot already loaded up on Kahoot's site.

Activity 7.9.4 (5 minutes)

Play a sample of music from a vinyl record and then the same music from a CD.  Can the students identify which is analog and which is digital?

Resources

• 7.9.2: Analog vs Digital Data Guided Notes (student resource)

• 7.9.2: Analog vs Digital Data Guided Notes KEY (teacher resource)