1. Foundations of Physical Science
Unit One: Forces and Motion

2. Chapter 1: Science and Measurement
1.1 Time and Distance
1.2 Investigations and Experiments
1.3 Speed

3. Learning Goals
Accurately measure time using electronic timers and photogates.
Use decimals to represent fractions of a second.
Develop a research question or hypothesis that can be tested.
Identify the variables that affect motion.
Develop an experimental technique that achieves consistent results.

4. Learning Goals (continued)
Draw conclusions from experimental results.
Accurately measure distance.
Identify metric and English units of distance.
Convert between units of distance.
Calculate speed in units of inches per second, feet per second, and centimeters per second.

5. Vocabulary cause and effect controlled experiment controlled variables
distance
English system
experiment
experimental technique
experimental variable
hypothesis
investigation
length
measurement
metric system
procedure
research question
scientific evidence
scientific method
second
time
trial
variables

6. 1.1 Time and Distance

7. Two Ways to Think about Time
What time is it?
How much time?

8. How is Time Measured? Time comes in mixed units.
Seconds are very short.
Hours and minutes are more convenient for everyday time measurement.

9. Electronic Timers Have displays that show mixed units.
To read a timer you need to recognize and separate out the different units.
Colons (:) separate the units.

10. Measuring Distance Describes how far it is from one point to another
Measured in units of length
Two common systems of units:
English (inches, feet, miles)
Metric (millimeters, centimeters, meters, kilometers)

11. Measurement and the English System

12. Measurement and the Metric System

13. Measurement
Units were invented so people could communicate amounts to each other.

14. 1.2 Investigations and Experiments

15. Designing Experiments
How do we ask questions and get answers from nature?

16. Experiment Any situation we set up to observe what happens.
In science, we usually plan our experiments to give us measurements, which are observations we can record and think about.
Experiments have questions associated with them.
Experiments are the way we ask questions of nature.

18. Scientific Method
Developed by Galileo and the English philosopher Francis Bacon in the 16th century
Based on rational thinking and experimentation

19. Designing Experiments
Start with a good question
Identify all the factors when designing experiments
Variables
Change 1 thing at a time
Control variables and experimental variables

20. Hypothesis
An educated guess about what will happen

22. Experimental Techniques
Experiments often have several trials
Experimental technique
Procedures
Scientific results must always be repeatable

23. Limitations Science deals only with hypotheses that are testable
Science is restricted to the observable natural world
Supernatural “above nature” cannot be explained
Philosophical questions cannot be answered

24. Pseudoscience Some belief systems are not science but pretend to be
Phrenology: the study of the surface bumps on a person’s head to identify health and personality

25. Pseudoscience
Astrology: the study of the stars and planets and their movements as well as their affects on the lives and behavior of human beings

26. The Search For Order
Science
Art
Religion

27. Technology Practical use of the findings of science
Science: concerned with gathering knowledge and organizing it
Technology: lets humans use that knowledge for practical purposes, and it provides the instruments scientists need to conduct their investigations

28. Technology Can be helpful and can be harmful
Example: find fossil fuels used in countless ways while damaging the environment
Technology is our tool to fix these problems

29. The Sciences Life Sciences: biology, zoology, botany, etc.
Physical Sciences: physics, chemistry, gemology, meteorology, astronomy

30. 1.3 Speed

31. What is Speed and How is it Measured?

32. What Do We Mean By Speed?
The speed of an object is a measure of how quickly the object gets from one place to another.
To determine a speed, you need to know two things:
the distance traveled.
the time taken.

33. Speed
distance traveled (m)
v = d t
speed (m/sec)
time taken (sec)

34. What’s the “v” for? Speed: the distance covered per unit of time
Velocity: speed and the direction of an object
Speed: 60 km/h
Velocity: 60 km/h due East
Vector Quantity: a quantity that specifies both magnitude and direction (example: velocity)

35. Concepts of Speed and Velocity
Constant speed: steady speed; doesn’t speed up or slow down
Constant velocity: both constant speed and constant direction

36. How to Solve Scientific Problems
Step 1
Identify what you are asked.
Step 2
Write down what you are given.
Step 3
Write down any relationships you know that involve any of the information you are asked, or given.
Step 4
Pick which relationship to start with and try to arrange it to get the variable you want on the left-hand side of an equal sign.
Step 5
Plug in the numbers and get the answer

37. Example
What is the average speed of a cheetah that sprints 100m in 4s? How about if it sprints 50m in 2s?
In both cases the answer is 25 m/s
Average speed = distance covered = 100m = 50m = 25m/s
time interval s s