JC Science - Measurements + Units

SI unit

Standard unit used around the world

SI unit for length

Metre

SI unit for mass

Kilogram

SI unit for time

Second

SI unit for temperature

Kelvin

Length

-Cm, m, km
-Length is a measure of distance

Instruments to measure length

-Metre stick
-Opisometer
-Trundle wheel
-Venir callipers

Opisometer

Venir callipers

Mass

-g, kg, ton
-Mass is a measure of how much matter something contains

Mass instruments

Electronic balance

what is Time

-s, m, h -A way of measuring + expressing duration

Time instruments

Clock

Temperature

-Kelvin, celcius + fahrenheit
-Temperature is a measure of how hot something is

0 degrees Kelvin in Celcius

-273

Instruments to measure temperature

Thermometer

what is Area

-A measure of the size of a surface of an object -Unit squared

Calculating the area of a rectangle + square

Length x width

Calculating area of irregularly shaped figures

Trace onto graph paper + count the number of squares covered

Calculating the surface area

-Calculate 1 side of a square then multiply by 6
-2(wxl)+2(lxh)+2(hxw)

Calculating volume of regularly shaped boxes

LxWxH

Calculating volume of liquid

Pour liquid into a graduated cyliner

Calculating volume of irregular objects

Overflow can + graduated cyliner

Using overflow can

1. Set up equipment
2. Fill overflow can with water
3. Place measuring cylinder under the can
4. Drop rock in
5. Measure the volume of water

Meniscus

-Curved surface of liquid in a graduated cylinder
-Always take the reading from the bottom of the meniscus

Precision

How close the measured values are to each other

Accuracy

How close a measured value is to the true value

Volume

cm3

Velocity

m/s

Energy

Joule

Current

amp, cm2

Force

Newton

Density

g/cm3 or gcm-3

Heat

°C

Dividing force by area

Pascal

Acceleration

m/s2

Moment of forc

Nm

Power

Watt