Can you read the message on this old phone? Why do you think people used to write “gr8” and “2nite” instead of “great” and “tonight”?
Image source: File:SMS composition on feature phone.png (Wikimedia Commons)
In this post:
- What SMS texting is and how it works
- What instant messaging (IM) is
- How they compare, and their good and bad points
- Using messaging for group work and teamwork
- A message-length tester, a sorting activity and a true/false quiz
SMS: text messages
SMS stands for Short Message Service. It is the “text message” feature built into every mobile phone, even a basic one with buttons.
- It travels over the mobile phone network, so it works without the Internet, wherever you have a signal.
- One SMS holds up to 160 characters (fewer if you use emoji). Longer messages are split into several parts.
- It sends text only. (Picture messages use a different service called MMS.)
- Each text may cost money, or come as part of your mobile plan.
- Banks and other services use SMS to send one-time codes and alerts, because it works on any phone.
Instant messaging (IM)
Instant messaging apps such as WhatsApp, Telegram, Messenger and Signal send messages over the Internet, using mobile data or Wi-Fi.
- You can send text, emoji, voice notes, photos, videos, documents and your location, and make voice and video calls.
- You can create group chats with many people.
- Most apps also work on a computer or tablet, not just a phone.
- You download the app (it does not need to come with the phone). Messages are free apart from the cost of data.
- Many apps show when a message has been delivered and read, and when someone is typing.
SMS vs IM
| SMS | Instant messaging | |
|---|---|---|
| Needs the Internet? | No, just a mobile signal | Yes, data or Wi-Fi |
| Works on a basic phone? | Yes | Usually no |
| What can you send? | Text (up to 160 characters per part) | Text, voice notes, photos, videos, files |
| Group chats? | Limited | Yes, easily |
| Cost | Per message, or in your plan | Free apart from data |
Messaging as social media
Group chats let people share news, photos and jokes with many friends at once, which makes messaging apps a kind of social media.
| Good points | Bad points |
|---|---|
| Quick and cheap way to keep in touch | Messages can be misunderstood without tone of voice |
| Easy to share photos, files and voice notes | Constant notifications distract from homework and sleep |
| Group chats help with teamwork | Rumours, forwarded fake news and unkind messages spread fast |
| IM apps work across countries | Messages and photos can be screenshotted and shared |
| SMS works anywhere with a signal | Strangers may try to contact you |
Teamwork with a group chat
A class or project group chat (set up with a teacher or parent’s permission) can help a team plan and share work. Agree on some rules first:
- Stick to the project topic.
- Be kind and patient: everyone reads at different times.
- Share files and decisions in the chat so nobody misses out.
- No messages late at night.
- Never share passwords, home addresses or other people’s photos.
Watch: where do your texts go?
This animated video explains the journey a text message takes from your phone to your friend’s phone.
Video: Where Do Your Texts Go? – AsapSCIENCE – https://www.youtube.com/watch?v=7sKp9R5BOEk
Activity: how many texts?
Try it: SMS length tester
Type a message and watch the counter. Try writing more than 160 characters, then try adding an emoji. What happens?
Activity: SMS, IM or both?
Try it: sort the features
Drag or tap each card into the right box.
SMS
Instant messaging
Both
Self-check quiz
Click the best answer. You get feedback straight away; only your first click counts towards your score.
1. True or false? You can only send an SMS from a smartphone.
2. True or false? SMS works without an Internet connection.
3. True or false? You can send photos and documents by SMS.
4. True or false? You can only use an IM app if it came already installed on your phone.
5. True or false? WhatsApp, Telegram and Messenger are popular instant messaging apps.
6. True or false? Instant messaging can only send text.
7. True or false? Instant messaging can work between a phone and a computer, and can send files.
8. True or false? IM messages always arrive instantly, even with no Internet.
9. True or false? The cost of SMS messages can be included in a mobile plan.
10. True or false? Instant messaging works without the Internet.
Related posts on islandclass.org
For later, in Forms 4–5 (CSEC IT): these go deeper and are for when you reach CSEC Information Technology.
Next: Setting Up and Using Email
Syllabus link: Forms 1–3 ICT curriculum, Module 4, Objective 4.5 – discuss the use of SMS texting and instant messaging technologies.
Attributions to media used in this post:
- SMS composition on feature phone.png – Miss Puzzle – CC BY-SA 4.0 (via Wikimedia Commons)
- Video: Where Do Your Texts Go? – AsapSCIENCE (YouTube)
Updates
2026/10/21
– Fixed the activity code so its buttons keep working.
© 2026 Vedesh Kungebeharry. All rights reserved.