How can we measure time?

Think

Cooking

Travel

Economy

Amount of each ingredient we'll need.
Cooking time required.

Distance to destination in kilometres.
How long the journey will take.
How long we'll be staying.
Departure times for planes or trains.
Budget for the trip.

Money we earn.
Our expenses.
How much we can save.

It's easy for us to measure time. Smartphones, watches and clocks are everywhere.

How did people measure time in the past? When did people start measuring time?

Before clocks of any kind, our ancestors could see cycles in nature that could be used as a reference to tell the time:

The succession of day and night.
The phases of the Moon.
The seasons.
The migration of animals.

What other natural cycles do you know? Which were the most important to human life in the past?

We count time in hours, minutes and seconds. All these units are parts of a larger reference: a year.

But, what is a year? Choose the right answer.

The movements of the Earth define our sense of time:

The Earth spins continually on its own axis from west-to east (counterclockwise). It takes 24 hours to complete one rotation. The rotation of the Earth causes the alternation of day and night.
The Earth moves around the Sun. It takes the Earth 365 days and six hours to complete one revolution. We call that period a year.

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Physics and chemistry are experimental sciences. They involve measuring different characteristics of matter or the changes it goes through. They are sometimes called the sciences of measurement.

But can we measure everything?

These are some of the instruments humans used in the past to measure time intervals.

Sundials The first sundials we know about date back to the sixteenth century BC, in Egypt and Mesopotamia. They use a shadow to measure the time of the day.	Water clocks The draining of water in a deposit is used to tell how much time has passed. These artifacts were first used around the same time as sundials, sixteenth century BC.
Hourglasses We don’t know for sure when hourglasses were invented, but it is believed to be around the fourteenth century AD.	Candle clocks A burning candle with marks on it could be used as a timer. They couldn’t be used to tell the time of the day, but the time that had passed after the candle was lit.

Which of these characteristics are magnitudes?

The question you need to ask yourself is: Is there an objective reference to compare them to?

Match each instrument with the magnitude it can measure.

Think

Temperature
Mass
Length
Atmospheric pressure
Time

Barometer
Ruler
Chronograph
Thermometer
Scale

We are usually checking the time:

To be punctual when we meet someone, whether it’s in person or online.
To know if it’s a good time for something. For example, it's 12:45. Is it too early for lunch?
In sports, to know when a match ends, how long a race takes or who was the fastest.
On a birthday, we are counting the time that's passed since someone was born.

Think and discuss

When we are waiting for a friend because we've made plans to meet, time passes very slowly. Epecially, if that friend is very late.

That sensation of time passing slowly is:

If we want to do an experiment in which we drop a ball from a certain height and we use a chronograph to measure the time it takes, our measurement will be:

,
You have completed the lesson!

Below is the time you have spent on the activity and the score you obtained.

Time spent

Score

How can we help you?

Couldn't find what you were looking for?

Please describe the issue you are experiencing and provide as many details as possible. Let us know the book, class, access device, licence code, username, used browser or if it occcurs in our app:

Homework – Let's remember

How many times a day do we measure something?

What about time?

How did people tell the time in the past?

Before clocks of any kind, our ancestors could see cycles in nature that could be used as a reference to tell the time:

What is a year?

We count time in hours, minutes and seconds. All these units are parts of a larger reference: a year.

But, what is a year? Choose the right answer.

The sky, our oldest clock

What can we measure?

Ways we measured time in the past

The first sundials we know about date back to the sixteenth century BC, in Egypt and Mesopotamia. They use a shadow to measure the time of the day.

The draining of water in a deposit is used to tell how much time has passed. These artifacts were first used around the same time as sundials, sixteenth century BC.

We don’t know for sure when hourglasses were invented, but it is believed to be around the fourteenth century AD.

A burning candle with marks on it could be used as a timer. They couldn’t be used to tell the time of the day, but the time that had passed after the candle was lit.

Let's test. Magnitudes

He is measuring his weight. We often use weight and mass as if they’re the same. But they are not:

Weight is the force that pulls the body towards the Earth.

Mass is the amount of matter.

Both are magnitudes.

Which of these characteristics are magnitudes?

The question you need to ask yourself is: Is there an objective reference to compare them to?

How do you measure that?

Match each instrument with the magnitude it can measure.

Classwork – Let's discover

How important is time in our daily lives?

Let's discuss. Can a scientific measurement be subjective?

When we are waiting for a friend because we've made plans to meet, time passes very slowly. Epecially, if that friend is very late.

On the Internet you can find many commercials selling miraculous products that cure all kinds of illnesses. Some will claim that they are beneficial because they “optimize your natural positive energy”.

Can you measure that “natural positive energy”? If not, how could you find out if it works?

That sensation of time passing slowly is:

If we want to do an experiment in which we drop a ball from a certain height and we use a chronograph to measure the time it takes, our measurement will be:

How can we help you?

Couldn't find what you were looking for?

Please describe the issue you are experiencing and provide as many details as possible. Let us know the book, class, access device, licence code, username, used browser or if it occcurs in our app:

Homework – Let's remember

How many times a day do we measure something?

What about time?

How did people tell the time in the past?

Before clocks of any kind, our ancestors could see cycles in nature that could be used as a reference to tell the time:

What is a year?

We count time in hours, minutes and seconds. All these units are parts of a larger reference: a year.

But, what is a year? Choose the right answer.

The sky, our oldest clock

What can we measure?

Ways we measured time in the past

The first sundials we know about date back to the sixteenth century BC, in Egypt and Mesopotamia. They use a shadow to measure the time of the day.

The draining of water in a deposit is used to tell how much time has passed. These artifacts were first used around the same time as sundials, sixteenth century BC.

We don’t know for sure when hourglasses were invented, but it is believed to be around the fourteenth century AD.

A burning candle with marks on it could be used as a timer. They couldn’t be used to tell the time of the day, but the time that had passed after the candle was lit.

Let's test. Magnitudes

He is measuring his weight. We often use weight and mass as if they’re the same. But they are not:

Weight is the force that pulls the body towards the Earth.

Mass is the amount of matter.

Both are magnitudes.

Which of these characteristics are magnitudes?

The question you need to ask yourself is: Is there an objective reference to compare them to?

How do you measure that?

Match each instrument with the magnitude it can measure.

Classwork – Let's discover

How important is time in our daily lives?

Let's discuss. Can a scientific measurement be subjective?

When we are waiting for a friend because we've made plans to meet, time passes very slowly. Epecially, if that friend is very late.

On the Internet you can find many commercials selling miraculous products that cure all kinds of illnesses. Some will claim that they are beneficial because they “optimize your natural positive energy”.

Can you measure that “natural positive energy”? If not, how could you find out if it works?

That sensation of time passing slowly is: Objective.Subjective.

If we want to do an experiment in which we drop a ball from a certain height and we use a chronograph to measure the time it takes, our measurement will be: Objective.Subjective.

That sensation of time passing slowly is:

If we want to do an experiment in which we drop a ball from a certain height and we use a chronograph to measure the time it takes, our measurement will be: