2. Studying Earth Science

3. Chapter Two: The Science Toolbox
2.1 Measurement
2.2 Measuring Time and Temperature
2.3 Systems and Variables
2.4 Graphs

4. 2.2 Measuring time
It is often important to measure time in experiments.
You are probably familiar with the common units for measuring time:
seconds, hours, minutes, days, and years.
How many seconds does it take to each lunch?

5. 2.2 Measuring time How do these units of time relate to each other?
How many seconds are in 1 hour?
How many seconds are in 30 minutes?

6. 2.2 Measuring time
It takes about 156 days to grow a pumpkin from a seed.
About how many months is 156 days?

7. 2.2 Measuring temperature
There are two commonly used temperature scales.
On the Fahrenheit scale, water freezes at 32 degrees and boils at 212 degrees.
On the Celsius scale, water freezes at 0°C and boils at 100°C.

9. 2.2 Measuring temperature
You can convert between Fahrenheit and Celsius using these formulas.

10. 2.2 Measuring temperature
Alcohol thermometers measure temperature as a change in volume of the alcohol.
The volume of alcohol in a thermometer contains huge numbers of alcohol molecules.
As temperature increases, the alcohol molecules move faster and bounce off each other.
The liquid alcohol expands and takes up more space in the thermometer.

11. 2.2 Measuring temperature
Digital thermometers sense temperature by measuring the ability of electricity to pass through a part of the thermometer called a probe.

12. 2.2 Measuring temperature
Aquarium “sticker” thermometers use chemical that changes color at different temperatures.

13. 2.2 Accuracy vs. precision
An accurate measurement is one that is factual.
Precise measurements are close to the same value.