Year 4 Science: Measuring carefully
Part of the Year 4 Science working scientifically revisited chapter. Chapter overview · whole chapter on one page
Measuring carefully
Careful measuring gives us accurate results. Use the right unit: millilitres (ml) for water in a measuring cylinder, and degrees Celsius (°C) for temperature on a thermometer.
To read a measuring cylinder, put it on a flat table, and read the bottom of the curved surface of the water at eye level. To read a thermometer, keep the bulb in the liquid, and do not let it touch the bottom or the sides of the container.
Key ideas
- Read a measuring cylinder in millilitres (ml), at eye level.
- Read a thermometer in degrees Celsius (°C), with the bulb in the liquid.
- Use a ruler in centimetres (cm) to measure length.
- A measurement needs a number and a unit.
Method. Read the scale at eye level.
- Find the level. The top of the water is at the line that is 40 ml on the scale.40 ml
- Check the unit. The reading is in millilitres, so the number is 40.millilitres
- Write the answer. 40
Check. The line between 30 and 50 is 40 ml. ✓
Method. Find the red liquid on the scale.
- Find the top of the liquid. The red liquid goes up to a point between 20 and 30.between 20 and 30
- Read the scale. The top of the liquid is two small marks above 20. Each small mark is 2 degrees, so the reading is 24 degrees Celsius.24
- Write the answer. 24
Check. Two small marks above 20, at 2 degrees each, make 24 degrees. ✓
Watch out. Read the top of the red liquid, not the bottom of the bulb.
Method. Add the extra length to the pencil.
- Read the lengths. The pencil is 9 cm, and the towel is 4 cm longer.9 cm and 4 cm
- Add them. 9 cm plus 4 cm makes 13 cm.9 + 4 = 13
- Write the answer. 13
Check. Check: 13 cm minus 4 cm is 9 cm. ✓
Watch out. Include the unit, centimetres, when you write the answer.
Watch out
Watch out: read the scale at eye level. Looking from above or below makes the level look higher or lower than it really is.
Try it at home or school (with a grown-up). Put 100 ml of water into a jug, using a measuring jug with a grown-up. Pour 40 ml into a cup and read the level with your eyes at the same height. Check your reading with a grown-up. Do not use hot water.
Exam tip
Grown-up tip. Ask: “What is the unit? Is your eye level with the water?” Let your child read the scale at eye level, and say the number and the unit together.
Exercise 1C Measuring carefully
Method. Read the level of the water.
- Find the line. The water level is at the 40 ml mark.40 ml
- Write the number. The number is 40.40
- Write the answer. 40
Check. The mark between 30 and 50 is 40. ✓
Method. Read the red liquid on the scale.
- Find the top of the liquid. The red liquid is between 20 and 30 degrees Celsius.between 20 and 30
- Read the mark. The top of the liquid is at 24 degrees Celsius.24
- Write the answer. 24
Check. The reading is two small marks above 20, and each small mark is 2 degrees. ✓
Method. Think about what a measuring cylinder measures.
- Think about the unit. Water in a measuring cylinder is measured in millilitres.millilitres
- Write the answer. ml
Check. Cm is used for length, not for water. ✓
Method. Think about what a thermometer measures.
- Think about the measurement. A thermometer measures temperature, in degrees Celsius.temperature
- Write the answer. degrees Celsius
Check. Litres are used for volume, not temperature. ✓
Method. Read the key idea in section 1.3.
- Read the key idea. Read the water at eye level, so the reading is not too high or too low.eye level
- Write the answer. eye level
Check. Looking from above or below gives a wrong reading. ✓
Method. Count up the marks in steps of 10.
- Find 40 on the scale. The scale goes 30, 40, 50 in steps of 10 ml.40, 50
- Name the next mark. The next mark above 40 is 50 ml.50
- Write the answer. 50
Check. Steps of 10 ml from 40 give 50. ✓
Method. Take the water away from the starting amount.
- Read the starting amount. The cylinder starts with 35 ml of water.35 ml
- Take away the pouring. 35 minus 10 is 25, so 25 ml is left.35 - 10 = 25
- Write the answer. 25
Check. Check: 25 ml plus 10 ml makes 35 ml. ✓
Method. Add the three trials, then divide by three.
- Add them. 40 plus 42 plus 41 makes 123.40 + 42 + 41 = 123
- Divide by three. 123 divided by 3 is 41.123 divided by 3 is 41
- Write the answer. 41
Check. Check: 41 + 41 + 41 = 123. ✓
Watch out. Divide by the number of trials, which is three.
Method. Count the measurements.
- Read the sentence. Aisha measured the paper towel, and then measured it again.measured again
- Count them. She made two measurements of the same length.2
- Write the answer. 2
Check. Repeating the measurement helps us check it. ✓
Method. Think about what the bulb should be in.
- Think about the bulb. The bulb should be in the liquid, not touching the cup.in the liquid
- Decide. A bulb touching the bottom measures the cup, so the reading is not correct.not correct
- Write the answer. no
Check. Keep the bulb in the liquid, away from the sides and the bottom. ✓
Method. Think about the number 40 on its own.
- Think about the number. The number 40 could mean 40 ml, 40 cm or 40 degrees.could mean
- Write the reason. The unit tells us what the measurement is, so the answer is clear.unit
- Write the answer. Accept any sentence that says a unit tells us what the number means, such as millilitres or centimetres.
Check. A number with a unit is a measurement. ✓