Grade by Grade
C. Matter and Energy · Light and Sound

Light and Sound Devices: How They Affect Our Lives

C1.1 A1.5 A3.1About 40 minutes
Learning goals
  • I can describe how devices that use light or sound help people.
  • I can describe problems some of these devices can cause.
  • I can weigh the good and the bad of a device and give my opinion with reasons.
  • I can explain how devices make communities more accessible for people who are Deaf, hard of hearing, blind or have low vision.
  • I can use safe habits with screens and headphones.

Words to know

society
All the people living together in a community or country.
impact
The effect something has, good or bad.
benefit
A good result; something that helps.
drawback
A bad result or problem.
accessible
Easy for everyone to use, including people with disabilities.
assess
To think carefully about something and decide how good or bad it is, with reasons.

A day without light and sound devices

Imagine one day with no light and sound devices. No alarm clock to wake you. No traffic lights at the corner. No smoke alarm. No phone to call Grandma. No music. No screens. How would your day be different? Would anything be better?

Devices that use light and sound have a big impact on society: on how people live, work, learn, play and stay safe. Most impacts are helpful, but some cause problems.

Benefits: how these devices help

  • Safety: smoke alarms and carbon monoxide alarms beep to warn us. Traffic lights, sirens, lighthouses and reflective strips help prevent crashes.
  • Communication: phones, video calls, radio and TV let us talk to family far away and learn news fast.
  • Health: eyeglasses, hearing aids, stethoscopes and ultrasound help people see, hear and stay healthy.
  • Learning and fun: screens, cameras, speakers and musical instruments.
  • Light at night: we can read, work and play safely after dark, which matters a lot during long Canadian winters.
A white lighthouse with a glowing light stands on a rocky shore beside big waves at sunset.
A lighthouse uses bright light to warn ships about dangerous rocks, one of many ways light devices keep people safe. AI-generated image

Devices that make communities accessible

Many devices help make communities accessible for everyone.

  • Some crosswalks have signals that beep or talk to tell people who are blind or have low vision when it is safe to cross.
  • Many fire alarms in public buildings flash bright lights as well as ringing, so people who are Deaf or hard of hearing know there is an emergency.
  • Hearing aids make sounds louder for people who are hard of hearing. Captions on videos show the words that are spoken.
  • Video calls let people who use sign language talk to each other from far away. In Canada, many Deaf people use American Sign Language (ASL) or Langue des signes québécoise (LSQ). These are full languages, not just gestures.

Drawbacks: problems these devices can cause

  • Hearing damage: headphones or earbuds that are too loud, for too long, can damage hearing forever.
  • Too much screen time can mean less time moving, playing outside and being with people. Screens right before bed can make it harder to fall asleep. Staring at a screen for a long time can make eyes feel tired.
  • Distraction: people looking at phones while walking or driving can get hurt or cause crashes.
  • Privacy: cameras and microphones in devices can record people.
  • Noise and light from devices can bother neighbours and wildlife (next lesson).

Healthy habits with screens and headphones

  • Keep headphones at a medium volume (a common tip: about 60% or less) and take listening breaks.
  • Try the 20-20-20 tip for your eyes: every 20 minutes, look at something about 20 feet (6 metres) away for 20 seconds.
  • Turn off screens a while before bed.
  • Look up from your phone when you walk, and never use a screen on your bike.
20minutes on a screen20feet (6 m) away20seconds of lookingEvery 20 minutes, look at something 20 feet away for 20 seconds.
The 20-20-20 tip in three steps. Giving your eyes a short break from close-up screens helps them feel less tired.
Worked example

Let's assess a device: headphones

Should students use headphones at school? Assess the impact of headphones.

  1. List the benefits: students can listen to a story or a video without bothering others; they can focus in a noisy room; some students who are easily overwhelmed by noise feel calmer with them.
  2. List the drawbacks: if the volume is too high, they can damage hearing; a student might not hear the teacher or a fire alarm.
  3. Think about different people: a student who likes quiet, a student who needs to block out noise, the teacher, a parent worried about hearing.
  4. Look for ways to reduce the drawbacks: set a volume limit, take breaks, take headphones off during instructions and drills.
  5. Decide and give reasons: "I think headphones are helpful at school if we use safe volumes and take them off when the teacher talks, because they help many students focus and the risks can be made small."

A good assessment lists benefits and drawbacks, thinks about different people, suggests ways to reduce harm, and ends with an opinion with reasons.

BENEFITSDRAWBACKS+ listen withoutbothering others+ focus in a noisy room- hearing damageif too loud- might miss the teacherHeadphones: benefits weigh a little more IF we use safe volume
To assess a device, put its benefits on one side and its drawbacks on the other. Ways to reduce drawbacks (like safe volume) can tip the balance.
DeviceA benefitA drawbackA way to reduce the drawback
headphoneslisten without bothering othershearing damage if too loudmedium volume, take breaks
phonecall for help, talk to familydistraction while walkingstop walking to look at it
security camerahelps keep homes safecan record neighbours (privacy)point it only at your own property
bright screenlearning and gamesharder to fall asleepturn it off before bed
Weighing the impacts of devices
Just for fun

Why did the smartphone need glasses?

It lost all its contacts!

Hands-on activity

Device impact report

You need: paper, a pencil, and a family member to interview.

  1. Choose a device that uses light or sound: for example, a smartphone, a smoke alarm, headphones, a hearing aid, a doorbell camera, a car horn, a traffic light, a TV.
  2. Interview a family member: "How does this device help you? Does it ever cause a problem? What did people do before it was invented?"
  3. Make a chart with two columns: Benefits and Drawbacks. Add at least 3 of each (use your interview and your own ideas).
  4. Suggest one way to reduce a drawback.
  5. Decide: overall, is the impact on society mostly good, mostly bad, or both? Write 2 or 3 sentences with reasons.
  6. Share your report with your family, like a scientist presenting findings.

What to look for: at least 3 benefits and 3 drawbacks that really fit the device, one sensible way to reduce harm, and an opinion with a "because". Different opinions are fine if they are explained.

Safety: if you test headphone volume, start low and turn it up slowly.

Your turn

1

What does impact mean?

2

Name one way a smoke alarm helps society.

3

Name one drawback of headphones.

4

How can a crosswalk signal help a person who is blind?

5

Why do some fire alarms flash bright lights?

6

What is one healthy habit with screens?

More practice: warm-up

1

Benefit or drawback: a phone lets you call 911 in an emergency.

2

Benefit or drawback: loud music in earbuds hurts your ears.

3

Name one device that helps people who are hard of hearing.

4

What does accessible mean?

5

Name two sign languages used by Deaf people in Canada.

More practice: on your own

1

Why are lights especially important for people in Canada in winter?

2

Give one benefit and one drawback of a doorbell camera.

3

Why is it dangerous to look at a phone while crossing a street?

4

How do captions on videos make them more accessible?

5

Your friend's headphones are so loud you can hear the music from beside them. What could you tell them, and why?

Challenge

1

Assess traffic lights: give two benefits, one drawback, and your opinion with a reason.

2

Why do people sometimes disagree about whether a device is good or bad? Give an example.

3

Think of a new device that uses light or sound to solve a problem in your community. Describe it and one possible drawback.

Check your understanding

Quiz

1.

Which device mainly helps keep people safe using sound?

2.

Which is a drawback of headphones?

3.

Flashing fire alarms make buildings more accessible for people who...

4.

To assess a device, you should...

5.

Which is a healthy screen habit?

6.

ASL and LSQ are...

For parents and teachers

Big idea: Ontario Grade 4 expectation C1.1 asks children to assess the impacts on society of devices that use the properties of light or sound. "Assess" means weighing benefits and drawbacks for different people and reaching a reasoned opinion. The interview report practises communicating findings (A1.5), and the lesson connects to real jobs and community helpers (A3.1).

How to help: Do the interview seriously; children love hearing what life was like before cell phones or video calls. Accept different opinions as long as they come with reasons.

Common difficulties:

  • Seeing devices as all good or all bad. Push for both columns.
  • Forgetting different points of view. Ask "Who might feel differently? Why?"
  • Respectful language: use phrases like "people who are Deaf", "people who are blind or have low vision". Many Deaf people see themselves as part of a cultural and language community, so avoid talking about Deafness only as a problem to fix.

Safety and health: this is a good time to set family rules for headphone volume and screens at bedtime.