Computer Science
Grade 3
20 min
Video Calls: Seeing and Talking to Friends
Students learn about video calls and how they allow face-to-face communication online.
What you'll learn
- Identify at least two things you need to have a video call.
- Explain in your own words one reason why people use video calls.
- Demonstrate how to point to the camera on a device they are using to make a video call.
Tutorial Preview
1
Introduction & Learning Objectives
Learning Objectives
Identify that video and sound are types of data.
Explain that clicking a button is an 'event' that tells the computer to do something.
Describe a video call using a simple 'if-then' conditional statement.
Sequence the steps required to start a video call.
Define key terms like 'data', 'event', and 'internet' in the context of a video call.
Have you ever waved to your grandma or a friend through a computer screen? 👋 How does your smile travel all the way to their screen?
Today, we'll learn the computer science magic behind video calls! We will discover how computers use data, events, and special rules called conditionals to let us see and talk to people far away. It's like being a digital detectiv...
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Key Concepts & Vocabulary
TermDefinitionExample
DataInformation that a computer can understand and send. In a video call, your picture and your voice are both types of data.When you laugh, the microphone turns the sound into 'sound data' for the computer to send.
EventAn action that the computer notices. Clicking a button or receiving a call are events.When you click the green 'Answer' button, you are creating an event that tells the computer to start the video call.
ConditionalA rule that tells the computer what to do, usually in an 'IF...THEN...' format. It helps the computer make choices.IF the person you are calling clicks 'Accept', THEN your video chat will begin.
Input DeviceA part of the computer that takes in information from you. Your camera and microphone are input...
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Core Syntax & Patterns
The Event-Action Rule
Event -> Action
Use this to understand how computers respond. When a specific event happens (like a mouse click), the computer performs a specific action (like starting a call).
The If-Then Call Rule
IF [condition is true] THEN [do this action]
This is how video call programs make decisions. For example, IF the internet is connected, THEN the 'Call' button will work. IF it's not connected, THEN it won't.
The Data Travel Path
You -> Input Device -> Computer -> Internet -> Friend's Computer -> Output Device -> Friend
This shows the journey your voice and picture data take during a call. It starts with you and ends with your friend seeing and hearing you.
4 more steps in this tutorial
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Challenging
An app lets you put a funny cat ears filter on your head during a video call. For this to work, what must the computer program figure out FIRST, before it can add the ears?
A.How fast your internet is
B.Where your head is in the video picture
C.If your microphone is muted
D.What time of day it is
Challenging
A programmer writes this rule for a video call app: `IF (user_clicks_end_call_button) THEN (stop_sending_video_data AND stop_sending_sound_data)`. What is the purpose of this code?
A.It correctly ends the call by stopping all data from being sent.
B.It mutes the user's microphone but leaves the camera on.
C.It makes the video quality better when the call ends.
D.It sends a text message to the other person.
Challenging
You are on a video call with a cousin in another country. There is a small delay, or 'lag,' between when you speak and when they hear you. Why does this happen?
A.Because they are in a different time zone
B.Because their computer is newer than yours
C.It takes time for the sound and video data to travel that far across the internet
D.Because you are speaking a different language
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Frequently asked questions
What grade level is "Video Calls: Seeing and Talking to Friends"?
Video Calls: Seeing and Talking to Friends is a Grade 3 Computer Science lesson on ExcelOS.
What will I learn in Video Calls: Seeing and Talking to Friends?
You'll be able to: Identify at least two things you need to have a video call; Explain in your own words one reason why people use video calls; Demonstrate how to point to the camera on a device they are using to make a video call.
Is "Video Calls: Seeing and Talking to Friends" free to practice?
Yes. You can read the tutorial preview for free, and signing up for a free ExcelOS account unlocks the full tutorial and all practice questions with instant feedback.
How many practice questions are included with Video Calls: Seeing and Talking to Friends?
This lesson includes 27 practice questions across multiple difficulty levels, each with instant feedback and explanations.