Exam practice

Observation is done with the help of sense organs.

The result we reach at the end of an experiment is called a conclusion.

The knowledge collected from a test or an experiment is called information.

The properties of a thing can be found through observations, tests and experiments. (“Estimation” is not needed.)

Observation is finding out the properties of things with our sense organs.

• Can be found: color, shape, size (roughly), smell, taste, sound, roughness or smoothness, hardness or softness, hot or cold.
• Can’t be found: exact length, mass, volume and temperature; whether it dissolves in water; whether it burns.

Any four:

• its exact mass (weight);
• its exact volume;
• whether it dissolves in water;
• whether it burns;
• its exact length;
• its exact temperature.

It is an experiment. We can’t find the exact weight by looking or lifting: that gives only a guess. We have to do something: put the thing on a balance and measure it. Finding out by doing is experiment.

• Observation: look at them (salt is white and grainy; oil is yellow and runny), smell them, touch them, taste a tiny bit. Salt is a solid. Oil is a liquid.
• Experiment: put each into water. Salt dissolves; oil floats on top and doesn’t mix. Measure the same amount of each with a spoon and weigh them on a balance. With a teacher, dip a cotton wick in oil and try to light it, as in a lamp: oil burns. Salt doesn’t burn.
• Inquiry: ask a teacher, read or search why salt dissolves and oil floats.

Then write a conclusion from all of these.

Inquiry helps us find the reasons behind what we observe and test.

• Example 1: Ayusha saw that a lamp doesn’t burn with milk. By asking and reading, she can learn why: milk is mostly water, and water doesn’t burn.
• Example 2: a farmer sees that his crop is poor. He asks other farmers and experts, and reads. He learns which seeds and manure suit his field. Next year, his crop is better.

So inquiry turns “what happens” into “why it happens”. It helps us make discoveries.

A drawing made with lines or symbols is called a schematic diagram.

A tripod stand is used to hold up a flask while it is heated.

It is easy to observe things in glass test tubes, beakers and flasks, because they are transparent.

A physical balance is used to measure the mass of a thing. (“Spring balance” is not needed.)

1. measuring cylinder
2. test tube
3. funnel
4. conical flask

(The beaker has no picture.)

Any four:

• Don’t close the mouth of the apparatus.
• Don’t shade or color it.
• Draw with single lines.
• Draw it flat (two-dimensional).
• Keep the sizes in the right proportion.
• Use a sharp pencil and a ruler.

Any three:

• They are quick and easy to draw.
• They show clearly how apparatus is set up, so others can repeat the experiment.
• Anyone can understand them, because everyone uses the same simple shapes.
• They show sizes in the right proportion, so things can be compared.

Your map will be your own. To draw it:

• Draw roads as two straight lines, and paths as one line.
• Draw your home, school, temple or shop as small squares or simple symbols, and write each name beside it.
• Keep things in the right places: if the temple is next to the square, draw it there.
• Add an arrow pointing north (N), and use a pencil and a ruler. No shading or color.

Draw them with single lines, flat, with no color, and with their mouths open, as in Figure 1.9.

• Tripod stand: a flat line for the top, with two legs slanting down and out.
• Beaker: a U with straight sides and a flat bottom, open at the top.
• Test tube: a long, thin U with a round bottom, open at the top.
• Conical flask: a narrow neck on top of a wide, sloping body with a flat bottom.

One thousand meters is equal to one kilometer.

One cubic meter is equal to 1000 liters. (A box 1 m long, 1 m wide and 1 m high holds 1000 liters of water.)

A flat shape with no height or thickness has a surface but no volume.

The fixed amount used to measure a quantity is called a unit.

Measurement is comparing an unknown amount with a known amount. (“Square meters” is not needed.)

(“Weight” is left over. In daily life we say a thing “weighs 2 kg”, but the kilogram is the unit of mass.)

• Mass is the amount of matter in a thing.
• Instruments: a physical balance with standard weights, a digital balance, and the weighing scales in shops.
• Units: milligram (mg), gram (g) and kilogram (kg). For very heavy things, quintal (100 kg) and tonne (1000 kg). 1000 g = 1 kg.

1 foot = 30.48 cm.
50 feet = 50 × 30.48 cm = 1524 cm.
100 cm = 1 m, so 1524 cm = 1524 ÷ 100 m = 15.24 m.

• Liquids: a measuring cylinder, a measuring jug, a measuring cup and spoon, a liter bottle, a syringe (for medicine), the meter at a petrol pump.
• Grains and other solids in small pieces: a mana and a pathi.
• Box-shaped solids: a ruler or measuring tape, to find length, breadth and height (V = l × b × h).
• Irregular solids: a measuring cylinder with water.

• Stopwatch: it starts at zero and counts up. It measures how long something takes. Example: timing a friend running 50 m (9.6 seconds).
• Timer: you set a time, and it counts down to zero. Then it rings, to tell you the time is over. Example: cooking rice for 15 minutes, or a 10-minute test.

For a small stone:

1. Pour some water into a measuring cylinder. Read its volume, say 50 ml.
2. Tie the stone to a thread. Lower it gently until it is fully under water.
3. Read the new level, say 62 ml.
4. Volume of the stone = 62 − 50 = 12 cm³.

Draw it as in Figure 1.18.

For a stone too big for the cylinder, fill a pot to the brim, stand it in a bowl, lower the stone in, and measure the water that spills out (Figure 1.19).

A floating thing won’t go under the water by itself. So she uses a sinker: a small stone that pulls it under.

1. Pour water into a measuring cylinder. Tie a small stone to a thread and lower it in. Read the level, say 60 ml.
2. Take it out. Tie the wood to the stone, so the stone pulls the wood under. Lower both in until the wood is fully under water. Read the level, say 75 ml.
3. Volume of the wood = 75 − 60 = 15 cm³.

She could also push the wood under with a very thin pin. The pin is so thin that it hardly changes the level.