Hello everyone.

This is Mr. James.

Are you ready for some more science learning? Are you feeling curious? Great, let's go.

Our lesson today is from the unit, "Introduction to Sound" And this lesson is about measuring the volume of sounds, and here's our learning outcome for today's lesson.

"I can use a data logger to take accurate measurements to compare the volumes of sounds." I'll run through the key words before we get started.

You can repeat them after me.

Compare, sounds, volume, data logger, decibels.

I'll bring up the meaning of those words now and you can read them for yourself, but remember, if you need to come back to them during the lesson, that's just fine.

Pause the video if you need to.

Got them? Great, let's move on.

So our lesson outline is this.

We're going to start with the measurement of sound, measuring sounds, and then we'll talk about comparing sounds.

Andeep and Jun compare how loud or how quiet different sounds are.

Andeep says, "I have to play music in my bedroom really quietly when my sister is revising for exams." Jun says, "I shout loudly to my teammates to pass the ball to me when I play hockey." What word describes how loud or quiet a sound is? Pause the video while you decide what that word is.

Got it? The children compare the volume of their voices in the school play.

Yes, the volume.

"I am the loudest.

You can hear my voice all the way across the hall." Says Andeep.

"I am the loudest.

Everyone in the audience said they could hear me from the stage." Said Jun.

How could we find out who is correct? What do you think? Pause the video if you need to talk about that.

Well, we can compare the loudness of different sounds by measuring their volume.

Do you know how we can measure how loud or quiet sounds are? Is there a scientific piece of equipment that we would need? What do you think? Talk about it if you need to.

You could pause the video.

Well then.

True or false? It is not possible to compare the loudness of different sounds by measuring their volume.

True or false? Yeah, it's false.

Now think about why that is.

Can you justify your answer? Here are a couple of suggestions.

Which one do you think is the best fit? You can use scientific equipment to measure volume, or B, you can look for sound waves travelling through the air to measure the volume.

Have a little think.

Which one do you think is the best answer? Yeah, you can use scientific equipment to measure volume.

Andeep and Jun are thinking about how to measure the volume of different sounds.

"I can place my hand on a speaker and measure the volume of sounds by feeling how large the vibrations are." Suggests Andeep.

"I've used a data logger for measuring how bright a light is." Says Jun.

"So I think I can use it for measuring how loud a sound is too." What do you think? Pause the video if you need to have a discussion.

Izzy has an idea to help the boys decide who is the loudest.

"You are correct, Jun! You can use a data logger with a sound sensor to measure the volume of sounds!" Do you know what a data logger is? Have you used one before? Pause the video if you need to talk about this.

Data loggers are electronic devices which monitor and record changes in the environment over time, such as temperature, sound, light, and movement.

The data logger shown has a tiny sound sensor inside so it can detect and record the volume of a sound and store this information as data.

I have one here.

Can you see the sound sensor marked here? What do data loggers measure? Changes in the weather, A.

Changes in the environment over time, B.

The time around the world, C.

What do you think? They measure changes in the environment over time.

That's right.

Andeep says, "Wow, I didn't know we could actually measure the volume of different sounds.

What unit of measurement do we use? Do data loggers have a special ruler for measuring volume?" Jun says, "A sensor inside the data logger measures the volume of sound and the data logger records this in decibels.

We can write this as dB." Just like Jun has shown you here.

The unit for volume is named in honour of Alexander Graham Bell, the inventor of the telephone and a device for checking your hearing called an audiometer.

What is the unit of measurement for the volume of a sound? Is it A, CS for changing sounds? B, dB for decibels? Or C, SV for sound volume? What do you think? Yeah, it's B, dB for decibels.

Task A now, measuring sounds.

Use a data logger with a sound sensor to measure and compare the volume of different sounds around your school or home.

Record your results in a table like the one below.

If you don't have a data logger, you could download a free sound metre app to an electronic device.

Pause the video so you can do this now.

Here are some results.

A teacher speaking, 60 decibels.

Whispering was 30, banging a drum hard, 130 decibels, and shouting, 70 decibels.

Are the volumes of sounds that you measured similar or different to these? Pause the video now if you want to talk about that.

last part of the lesson now, comparing sounds.

Scientists and engineers take accurate measurements to compare and control the volume of sounds.

They need to decide what is a safe level of noise so it's not harmful or or dangerous to our ears.

Jun says, "I think listening to fireworks is an acceptable level of sound because lots of people attend a firework display." What do you think? Pause the video now if you want to have a discussion about that.

Scientists and engineers consider the volume of sound from fireworks to be dangerous if you're listening to them for a long period of time.

It's advised that you wear protective equipment such as ear defenders if you are going to a firework display to protect your ears.

If you agree with that, say yes on the count of three.

One, two, three.

Pardon? I couldn't hear a word you said.

What other high volume sounds may be harmful to your hearing? Have a chat about that now.

You can pause the video.

High volume sounds could include noisy equipment and machinery that can reach volumes up to 120 decibels.

Or music in entertainment venues that can reach volumes between 105 and 110 decibels.

Why do scientists and engineers need to take accurate measurements of the volume of sound? Is it A, they need to make sure the volume is really loud? B, it's their job to measure the volume of sounds? Or C, to ensure the volume is not too loud and isn't harmful to our ears? What do you think? Yes, it's the last of those, to ensure the volume isn't too loud and isn't harmful to our ears.

Jun is researching how a sound engineer might take measurements to compare and control the volume of sounds.

"I think music at a music concert would be considered harmful as it's quite loud.

I wonder how a sound engineer controls the volume at a concert to make it safe?" What do you think? Pause the video if you want to have a talk about that now.

A sound engineer would monitor the sound level in decibels throughout the concert using equipment like data loggers and sound metres.

Here's a console that allows a sound engineer to control the volume.

They can adjust it.

They can adjust the volume in real time to maintain safe levels for the audience.

Andeep and Jun discuss how they can measure and control the volume of sounds.

Andeep says, "I will use a data logger to measure the volume of sounds at the school disco.

If the music's too loud, the DJ can turn down the volume." Jun says, "I'll use a sound metre app on my tablet to measure the volume of sound at band practise.

If the volume's too high, we'll need to play quieter." Which of the following would an engineer use to take measurements to compare the volume of sounds? A, a ruler? B, a digital thermometer? Or C, a data logger with a sound system? What do you think? Yes, it's one of these, a data logger with a sound sensor.

Well done.

Time for task B.

You're going to predict the volume in decibels of some everyday sounds.

Sounds that might include normal breathing, wind blowing, kettle boiling, school bell ringing or music in earphones.

Be sure you've got someone's help if you are boiling a kettle though.

Now, you can predict the volume in decibels on the table here, but you can also then go on to measure the actual volume in decibels.

And for that of course you are going to need a data logger or if you haven't got one of those, a sound metre app which you can download as we said, to an electronic device.

Pause the video now and then you can get predicting and measuring.

How did you get on? Here are some results.

You can see the predictions.

Were they close to your predictions? Were they similar or were they quite different? Also you can see the actual volume recorded.

So the actual volume of normal breathing was 10 decibels on this measurement.

Wind blowing, 85 decibels.

Remember though that wind blowing can be different on different days, so this is somebody's recordings.

Yours may well be different.

Kettle boiling, and again, kettles are different.

These results recorded the kettle boiling at 90 decibels.

The school bell ringing.

School bells, are they all the same or are some different? Yes, they can be different.

And maybe if you're working at home, you used a different sorted bell, a doorbell perhaps.

So the school bell ringing was 120 decibels.

Not quite as loud as the prediction you notice.

And the music in the earphones, that came out at 87 decibels, which was slightly quieter again than the prediction thought it would be.

Well done with all that investigating and measuring and predicting.

Should we sum up what we've been learning today? We've learned that we can compare the loudness of different sounds by measuring their volume.

Data loggers are electronic devices which monitor and record changes in the environment over time.

The volume of a sound in decibels, dB, can be measured using a data logger and a sound sensor.

And scientists and engineers take accurate measurements to compare and control the volume of sounds.

Good work, see you next time.