Scientific Learning

When we see something new, we want to touch it, look at it and ask about it. This wish to know is curiosity. While we look for an answer, we learn something new.

To answer our questions, we do these things:

• observe: look carefully, using our senses;
• measure: find out exactly how long, how heavy or how much;
• classify: put things into groups;
• estimate: make a sensible guess;
• test: try something out to see what happens.

These are the skills of science. Scientists use them every day.

Scientific learning starts with observation: finding out about things around us with our sense organs.

Some things we learn at once. A hot cup is hot the moment you touch it. Other things take more work. We need to try again and again, do experiments, ask questions and gain experience.

To know the exact amount of something, we measure it. We use different instruments for different things: a ruler for length, a balance for mass, a clock for time.

We also do experiments and ask questions to find out why things happen. Reaching an answer in this way is the scientific learning process. It uses observing, estimating, asking, comparing, testing, classifying and experimenting. When people keep doing this, they make discoveries.

Things around us look different from one another. A stone is hard and gray. Milk is white and runny. Each thing has its own properties: its color, shape, smell, taste, hardness and so on. We find out about properties in three ways: by observation, by experiment and by inquiry.

Observation

How did you fill in the table? You used your sense organs: the eyes, ears, nose, tongue and skin.

• With our eyes we see color, shape and size.
• With our ears we hear sounds.
• With our nose we smell.
• With our tongue we taste.
• With our skin we feel whether a thing is hard or soft, rough or smooth, hot or cold.

Finding out the properties of things with our sense organs is called observation. It is the first step of scientific learning. It tells us how a thing looks from outside: its shape, color, taste and so on.

When we observe something carefully and closely, we learn a lot about it. What we learn is called information.

Some instruments help us observe better. A hand lens and a microscope make small things look bigger. A doctor’s stethoscope lets her hear your heartbeat clearly.

But our senses can’t tell us the exact amount of anything. Your hand can tell that tea is hot. It can’t tell you how hot. For exact amounts, we use measuring instruments: a pan balance for mass, a thermometer for temperature, a clock for time and a scale (ruler) for length.

A guess made by looking and lifting is called an estimate. Pasang made a good estimate. But only the balance could say for sure.

Experiment

Observation tells us color, roughness and shape. But some properties can’t be found by observation:

• the exact volume of a thing;
• whether it dissolves in water;
• its exact weight (mass);
• whether it burns or not.

For these, we have to do an experiment. An experiment is an important step of scientific learning. It is also called learning by doing.

Experiments tell us more about a thing. They also let us give its properties as numbers. “The stone has a mass of 250 g” says much more than “the stone is heavy”. Numbers are easy to tell others, and others can check them. To find a thing’s length, its mass, or what is inside it, we have to do something: measure it, weigh it or open it.

An experiment tells us whether our guess is right or wrong. But it may not tell us the reason. To find the reason, we need to study more and ask more.

Inquiry

Finding out by asking questions, reading and searching is called inquiry. Inquiry helps us find answers to our curiosity. It helps us find the reasons for things that happen in nature.

Great discoveries come from inquiry and research. A new thing is rarely made in one try. It takes many questions and many tries.

We draw a conclusion, our final answer, from what we learn by observation, experiment and inquiry. Making new things after long tests and research in a laboratory is also scientific learning.

Scientific learning is not only for scientists. Everyone can use it.

• Shyam’s neighbor is a hard-working farmer. He wants better crops than anyone in the village. He asks questions, reads, watches his fields and tries out new seeds and manure. That is scientific learning.
• Sita’s mother cooks delicious food. She wants it tastier and healthier. She has visited places to watch others cook. She reads newspapers and searches the internet for ideas. That is scientific learning too.

1. Choose the best answer

2. Is it correct (✓) or wrong (✗)?

3. Fill in the blanks

information, sense organs, properties, estimation, conclusion

4. Answer these questions

In science we observe, measure and test. For this we need instruments, called apparatus (say: a-pa-RAY-tus).

Think of your kitchen. To cook food we need heat. It comes from firewood, gas or electricity. We cook in pots and pans. We keep the pot up over the fire on a stand: a ring of bricks or stones, an iron odaan (tripod), or the top of a gas stove. A science laboratory works the same way. It has its own heater, stands and pots.

Apparatus like this are used for observing, testing and experimenting. In a laboratory, we use only small amounts of chemicals, called samples. So lab apparatus is small. Many have a scale marked on them, to measure how much is inside.

Some apparatus used often in a laboratory

No.	Apparatus	What it is used for
1.	Bunsen burner	to make heat (it burns gas)
2.	Tripod stand	to hold up a beaker, flask or basin while it is heated
3.	Conical flask	to keep and mix chemicals (its narrow neck stops spills when you swirl it)
4.	Round-bottom flask	to mix and heat chemicals
5.	Measuring cylinder	to measure the volume of a liquid
6.	Standard weights	to find an unknown mass, by balancing it on a balance
7.	Physical balance	to measure mass
8.	Spring balance	to weigh a thing, by how far it stretches a spring
9.	Thermometer	to measure temperature
10.	Test tube	to mix and heat small amounts of chemicals
11.	Funnel	to pour liquids into a narrow mouth, and to hold filter paper
12.	Condenser	to cool a gas (vapor) back into a liquid
13.	Porcelain basin	to heat chemicals and to evaporate a liquid
14.	Beaker	to mix and heat chemicals
15.	Digital balance	to measure mass; it shows the number on a screen
16.	Wire gauze	to spread the burner’s heat evenly under a beaker

Schematic diagrams

Think of a beautiful old house in Bhaktapur. A photo shows every brick, every carved window and every color. Now draw it quickly with a pencil: a few lines for the walls, the roof and the windows. Which is easier to draw? The line drawing, of course. And it still shows what the house is like.

A drawing made with simple lines or symbols is called a schematic diagram. In science, we use schematic diagrams to show the apparatus of an experiment and how it is set up.

• An engineer’s plan for building a house is a schematic diagram.
• A drawing of lab apparatus and how it is arranged is a schematic diagram.
• A drawing of an electric circuit is a schematic diagram.

Rules for drawing a schematic diagram

1. Don’t close the mouth (top) of the apparatus.
2. Don’t shade or color it.
3. Use a single line.
4. Draw it flat (two-dimensional).
5. Keep the sizes in the right proportion: a test tube is smaller than a beaker.
6. Use a sharp pencil and a ruler.

Make a chart of these rules and put it up on the class board.

1. Choose the best answer

2. Is it correct (✓) or wrong (✗)?

3. Fill in the blanks

tripod stand, transparent, schematic, physical balance, spring balance

4. Match the name with the picture

5. Answer these questions

In daily life, we buy and sell many things. We measure them to know the exact amount.

• Length is measured with a meter scale, a ruler or a measuring tape.
• Mass (weight) is measured with a balance and standard weights.
• Time is measured with a clock.
• Volume, the space taken up by milk, curd, oil or water, is measured with a mana, a pathi or a measuring cylinder.

Measurement of length

Which tools have you used to measure how long, wide or tall a thing is?

Look at two pencils side by side. You can tell which one is longer. But how much longer? To find out, you must measure. And to measure, you need something whose length is already known. A meter scale, a ruler and a measuring tape all have known lengths.

Suppose you want the length of the class board. You lay a meter scale along it. The scale fits along the board exactly two times. So the board is 2 meters long.

Here the meter scale is the known, or standard, length. The length of the board is the unknown length. Comparing an unknown amount with a known amount is called measurement. The known amount we compare with is called a unit. The meter is a unit of length.

Look closely at a ruler. The big numbers mark centimeters (cm). Between two numbers there are 10 small spaces. Each small space is one millimeter (mm).

Length is measured in millimeters (mm), centimeters (cm), meters (m) and kilometers (km). These are units of length. Choose the unit that suits the size of the thing.

Small unit	Big unit
10 mm	1 cm
100 cm	1 m
1000 m	1 km

• The thickness of a coin: in millimeters.
• A pencil: in centimeters.
• A room: in meters.
• The road from Bhaktapur to Pokhara: in kilometers.

To change a big unit into a small one, multiply. To change a small unit into a big one, divide.

Length is also measured in inches, feet, yards and miles. A carpenter or a tailor in Nepal often uses feet and inches.

Unit	Is equal to
1 meter	100 cm, about 39.4 inches, about 1.09 yards
1 yard	about 0.91 m (3 feet)
1 foot	30.48 cm (12 inches)
1 inch	2.54 cm
1 centimeter	about 0.39 inches

Measurement of mass

Everything is made of tiny particles, far too small to see. In some things the particles are packed tightly. In others they are packed loosely, with lots of space between them. In air they are very loosely packed. In a stone they are packed tightly.

So a glass of gravel holds much more matter than a glass of cotton. That makes it heavier. The amount of matter in a thing is called its mass.

We can’t find the exact mass of a thing by looking at it. We can only guess which of two things is heavier. To find the exact mass, we must measure it.

We measure mass by comparing a thing with things whose mass we already know. Pieces of metal with a known mass are called standard weights (in Nepali, dhak). A physical balance compares the unknown mass with the standard weights.

The particles of each thing are packed differently. So things with equal mass may take up different amounts of space. A kilogram of cotton takes up much more space than a kilogram of rice.

Mass is measured in grams (g) and kilograms (kg).

1000 g = 1 kg

So half a kilogram is 500 g, and a quarter of a kilogram is 250 g.

Measurement of time

The Sun rises this morning. That is an event: something that happens. Tomorrow morning, the Sun rises again. That is another event. The time between these two events is one day.

Events happen all the time. Some happen in nature: the Sun rises and sets, rain starts and stops. Some are made by people: a class starts and ends, an exam starts and ends. The gap between any two events is time. We measure time with a clock or a watch.

Measurement of volume

Everything is made of matter. And all matter has mass and volume. A small lump of clay has a small volume. A big lump of clay has a big volume.

The space taken up by a thing is called its volume. It depends on the thing’s length, breadth (width) and height.

Number of boxes in a pile = number along the length × number along the width × number up the height

In the same way, the space taken up by a box-shaped thing is:

volume = length × breadth × height

or, in short:

$$V = l \times b \times h$$

This works for regular things, shaped like a box: a duster, a board, a book, a desk, a bench. If the length, breadth and height are in centimeters, the volume is in cubic centimeters (cm³). If they are in meters, the volume is in cubic meters (m³).

A liquid has no fixed shape. It takes the shape of its container. But it has a fixed volume.

Think of a hollow cube, 10 cm long, 10 cm wide and 10 cm high. Its inside volume is 10 × 10 × 10 = 1000 cm³. The water that fills it is one liter.

1 liter = 1000 cm³ = 1000 ml
so, 1 cm³ = 1 ml

A measuring cylinder is a tall glass or plastic jar with a scale in milliliters. It measures the volume of a liquid. Measuring cylinders come in many sizes: 10 ml, 25 ml, 50 ml, 100 ml, and bigger.

When you measure the volume of a liquid in a measuring cylinder:

• a.Stand the cylinder on a flat table.
• b.Keep your eye level with the surface of the liquid.

The volume of a stone

A stone has no neat length, breadth or height. Its shape is irregular. How can we find its volume? Water can help.

Find the volume of other solids in the same way: an eraser, a piece of brick, a key. Compare them, and write a conclusion.

No.	Thing	Volume of water (ml)	Volume of water and thing (ml)	Volume of the thing (cm³)
1.	eraser
2.	stone, piece of brick

1. Choose the best answer

2. Is it correct (✓) or wrong (✗)?

3. Fill in the blanks

unit, kilometer, square meters, volume, cubic meter, measurement

4. Match the units with what they measure

5. Answer these questions