Page 502 - Canadian BC Science 9

Instant Practice—Measuring Angles
1. State the measure of each of the following angles using the following diagram.
E
(a) 􏰈DAF (b) 􏰈DAH (c) 􏰈IAG
(d) 􏰈HAF (e) 􏰈GAD (f) 􏰈DAI
(g) 􏰈EAG (h) 􏰈EAI (i) 􏰈FAG
FG
90
H DAI
2. Use a protractor to draw angles with the following measures. Label each angle. (a) ABC 50° (c) XYZ 5° (e) HAL 90° (b) QRS 85° (d) JKL 45°
Measuring Temperature
Temperature is a measure of the thermal energy of the particles of a substance. In the very simplest terms, you can think of temperature as a measure of how hot or how cold something is. The temperature of a material is measured with a thermometer.
For most scientific work, temperature is measured on the Celsius scale. On this scale, the freezing point of water is zero degrees (0°C) and the boiling point of water is
100 degrees (100°C). Between these points, the scale is divided into 100 equal divisions. Each division represents one degree Celsius. On the Celsius scale, average human body temperature is 37°C, and a typical room temperature may be between 20°C and 25°C.
The SI unit of temperature is the kelvin (K). Zero on the Kelvin scale (0 K) is the coldest possible temperature. This temperature
Tips for using a thermometer
When using a thermometer to measure the temperature of a substance, here are three important tips to remember.
• Handle the thermometer extremely
carefully. It is made of glass and can break
easily.
• Do not use the thermometer as a stirring
rod.
• Do not let the bulb of the thermometer
touch the walls of the container.
is also known as absolute zero. It is equivalent to 􏰂273°C, which is about 273 degrees below the freezing point of water. Notice that degree symbols are not used with the Kelvin scale.
Most laboratory thermometers are marked only with the Celsius scale. Because the divisions on the two scales are the same size, the Kelvin temperature can be found by adding 273 to the Celsius reading. This means that on the Kelvin scale, water freezes at 273 K and boils at 373 K.
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