Checkpoint Physics Grade 8
Measuring distance , mass and time
,Lenses
Convex lens
Concave lens
Estimating quantities
A length written as 10 cm means that the length may be 9.5 cm or 10.5
cm . The difference between the two extremes is 1.0 cm
A length written down as 10 cm means that the length may be 9.95 cm
or 10.05 cm . The difference between the two extremes is 0.1 cm
A length written down as 10.00 cm means that the length may be 9.995
cm or 10.005 cm . The difference between the two extremes is 0.01 cm
, Volume
Measuring volume of a regular shape
The volume of a regular shape is found by multiplying the length by the
width by the height
Volume = L x W x H
Measuring the volume of a liquid
The volume of a liquid can be found by pouring it into a measuring
cylinder and reading the scale on the cylinder
When measuring the volume of a liquid we always measure under the
Meniscus
Measuring the volume of an irregular object
An irregular object cannot be measured easily as it has no sides such as a
pebble
To measure the volume of an irregular object you must pour water into a
measuring cylinder until it is half full for example 50 ml
Then you put your irregular object into the measuring cylinder with the
water and the water should rise unless the object is less dense than
water . You now take the measurement of the cylinder again lets say the
water has risen to 55ml , you must take 55 ml and subtract it from 50
ml and your volume of your irregular object will be 5 ml or 5cm₃
Heat and temperature
Finding the hotness or the coldness of something we must measure the
temperature of it
Measuring distance , mass and time
,Lenses
Convex lens
Concave lens
Estimating quantities
A length written as 10 cm means that the length may be 9.5 cm or 10.5
cm . The difference between the two extremes is 1.0 cm
A length written down as 10 cm means that the length may be 9.95 cm
or 10.05 cm . The difference between the two extremes is 0.1 cm
A length written down as 10.00 cm means that the length may be 9.995
cm or 10.005 cm . The difference between the two extremes is 0.01 cm
, Volume
Measuring volume of a regular shape
The volume of a regular shape is found by multiplying the length by the
width by the height
Volume = L x W x H
Measuring the volume of a liquid
The volume of a liquid can be found by pouring it into a measuring
cylinder and reading the scale on the cylinder
When measuring the volume of a liquid we always measure under the
Meniscus
Measuring the volume of an irregular object
An irregular object cannot be measured easily as it has no sides such as a
pebble
To measure the volume of an irregular object you must pour water into a
measuring cylinder until it is half full for example 50 ml
Then you put your irregular object into the measuring cylinder with the
water and the water should rise unless the object is less dense than
water . You now take the measurement of the cylinder again lets say the
water has risen to 55ml , you must take 55 ml and subtract it from 50
ml and your volume of your irregular object will be 5 ml or 5cm₃
Heat and temperature
Finding the hotness or the coldness of something we must measure the
temperature of it
