Contact and Book Info

1. Contact and Book Info Phillip Philpot pphilpot@cherokeecharter.org Textbook Georgia Science Grade 8, Glencoe Science, (Academic Students) Physical Science, Glencoe Science, (Cambridge Students)

2. 1-1What is Physical Science? Natural Science is divided into 3 main branches: • Physical Science • Earth and Space Science • Life Science In this class we will be focusing on Physical Science, which mainly focuses on the study of non-living things.

3. So what is Physical Science? • Physical Science is the study of matter, energy, and the changes they undergo. • Matter is anything that has mass and occupies space. • Energy is the ability to do work or cause change. • Turn to page 8 in your textbooks. • What are the 2 main branches of Physical Science?

4. Branches of Physical Science PHYSICS CHEMISTRY Study of the properties of matter and how matter changes Learn about the particles that make up matter and properties of different forms of matter Hydrogen alone is combustible. Oxygen alone is combustible. When combined in the form of water, H2O, they put out fire! Why? • Study of matter, energy, motion, forces, and how they interact • Learn about different forms of energy • Apply the laws of physics that govern energy to Earth, the solar system, and the universe beyond • Ever wonder how a laser works? A physicist knows!

5. Why Study Physical Science? Because it is used everyday in the real world! Who can think of some examples of when Physical Science is used in real life? Consider these examples: • The water you shower with is heated by chemical fuel or electricity • You use force to crush food when you eat • The food you eat is converted into chemical energy that your body uses to perform all of your daily tasks • There are chemicals in toothpaste you use to brush your teeth

6. BIG ideas of Physical Science • force and energy • the laws of conservation • atoms, molecules, and the atomic theory • The behavior of particles of matter in solids, liquids, and gases

7. Skills Scientists Use: Observing- Using one or more senses to gather information. 2 Types of observations: 1) Qualitative Observations- Do not involve numbers or measurements, “That man is tall.” 2) Quantitative Observations- Involve measurements, “That man is 6’5” tall.” Inferring (or making an inference)- Based on your observations or what you already know; not always correct. Predicting- making forecast of what will happen in the future based on past experience or evidence

8. Observation Versus Inference!

9. Now you try! In your notes, classify the following as observations or inferences:

10. How did you do?  INFERENCE  OBSERVATION  OBSERVATION  INFERENCE

11. 1-2Scientific Inquiry What is Scientific Inquiry? • How do scientists investigate the natural world? • What role do models, theories, and laws play in science? Scientific Inquiry refers to the different ways scientist study the natural world. It is the ongoing process of discovery in Science. In the process of scientific discovery, scientists use curiosity, honesty, open-mindedness, skepticism, and creativity. Why are these good qualities for a scientist to have?

12. Process of Inquiry Includes: Posing questions Developing hypotheses Designing experiments Collecting and interpreting data Drawing conclusions Communicating ideas and results

13. Chapter 1 Introduction to Physical Science The Nature of Inquiry • There is no set path that a scientific inquiry must follow. Different scientists may choose different paths when studying the same event. The Scientific Method • The scientific method is a more linear, organized way to inquire about science. • It always starts with an observation. • Copy the flow chart to the left, but add a bubble to the top that says “Make Observations.”

14. Step #1: Observations Observations lead to a question or problem Example: You enter a dark room and you observe that the lights are not turning on. This should lead you to the Question (Step #2) “Why are the lights not working?”

15. Step #3: Background Research Research will help you form a hypothesis that makes sense. You could use the internet, books, or even talk to knowledgeable people to see what could be possibly causing the lights to not turn on. Example: Possible explanations you come up with could be that the light bulb burnt out, or the electrical outlet is not working, or the breaker needs flipped, etc… Who can think of some other possible explanations?

16. Step #4: Hypothesis Form a hypothesis (possible explanation for observations) -Use the research you just did! -Understand that your hypothesis is only ONE possible explanation, and may not be correct! Example: You hypothesize that the light bulb has burnt out.

17. Step #5: Test the Hypothesis with an Experiment Collect data through observation or measurement Qualitative: characteristics (ex: red hair) Quantitative: numbers (ex: plant height= 32cm) Example: Check other known-working light bulbs in the lamp to see if the light will turn on.

18. Controlled Experiments…only 1 thing ( called a variable) changes *Variable that is deliberately changed= manipulated variable (independent variable) What is the independent variable in this experiment? (Hint: What are we changing?) *Variable that is observed and changes in response= responding variable (dependent variable) -What is the dependent variable in this experiment? (Hint: What is changing because of our independent variable?) THE LIGHT BULB! WHETHER OR NOT THE LIGHT TURNS ON!

19. Controlled Experiments… *All other variables in the experiment are held constant, which means they never change= controlled variable (constant variable) -What are some of the controlled variables in this experiment? *Why would a scientist want to use a controlled experiment? THE LAMP, THE ROOM, THE ELECTICAL OUTLET

20. Step #6 (Part I): Record & Analyze Data Organize your data into charts and graphs so that it is easier to recognize patterns Example:

21. Step #5: Draw Conclusions Decide if the evidence supports or rejects your hypothesis. Example: All light bulbs in that lamp plugged into the same outlet are not functioning, therefore I will reject my initial hypothesis because it is unlikely that all light bulbs are burnt out. Rejecting your original hypothesis is valid information because it helps you rule out possible causes to the problem or question and allows you to make a new hypothesis and start the steps of the scientific method over again.

22. Since our Hypothesis was not correct, we will go back to step #4 and form another hypothesis that we can test…. ANY IDEAS??? • After we form our new hypothesis, we will go back through the steps of the scientific method! • Once we find a hypothesis that is correct, we have answered our question! • In larger experiments, scientists will write up lab reports, repeat their experiments, publish their results, or even branch out from the experiment to test other ideas.

23. Why would scientists want to write lab reports and/or publish their results? So other scientists can learn from their data, and to possibly receive credit for their work. Why would scientists want to repeat their experiments? To make sure their results are accurate.

24. When does a hypothesis become a theory? • When a hypothesis is tested and confirmed enough times that it is unlikely to be proven wrong by future tests • In science, the word theoryapplies to a well-tested explanation that brings together a lot of observations • A theory may be changed or replaced as new evidence is discovered

25. What is a Law? Theories Versus Laws: • Laws DESCRIBE! • Theories EXPLAIN! A law is a statement that describes what scientist expect to happen every time under a particular set of conditions. It describes an observed pattern without attempting to explain it. Laws have been verified over and over again. Example: The Law of Gravity- states that all objects in the universe attract each other.

26. Chapter 1 Introduction to Physical Science Section 1-3:Measurement • Why do scientists use a standard measurement system? • What are the SI units of measurement for length, mass, volume, density, time, and temperature?

27. Chapter 1 Introduction to Physical Science A Standard Measurement System • Using SI as the standard system of measurement allows scientists to compare data and communicate with each other about their results. SI units are based on multiples of 10. We will be using SI and other metric units.

28. The Metric System • The SI system is considered to be the modern metric system. • It is considered a universal language for scientists, doctors, the military, and most countries. • The US is one of the only countries not on the metric system. • We use The English System which includes mph, feet, pounds, gallons, Farenheit, etc.. Why do you think the US has not switched to the Metric System?

29. Chapter 1 Introduction to Physical Science Length • The basic unit of length in SI is the meter (m). • To measure something larger than a meter, scientist may use kilometers (km), which means one thousand. • To measure something smaller than a meter, scientists may use centimeters (cm), centi- means one-hundredth, or millimeters (mm), milli- means one-thousandth.

30. Consider a ruler • This ruler shows both Metric and English units for measuring length • The numbers on the top are centimeters • The tiny lines within each centimeter are millimeters. • Notice there are 10 mm in 1 cm. COUNT THEM! • How many mm are in 3 cm? • The numbers on the bottom are inches • Notice how much bigger 1 in is compared to 1 cm • There are 2.54 cm in 1 in • We will practice converting from Metric to Metric and from Metric to English later!

31. WEIGHT vs MASS Weight: Mass: Mass is the measure of the amount of matter an object contains. Mass is not affected by gravity. If you travel to the moon, the amount of matter in your body (your mass) will not change. Scientists prefer to use mass rather than weight. SI unit of mass is the kilogram (kg), but we will be using mostly grams (g) in this class. WHY? • Your weight is a measure of the force of gravity on you. • The force of gravity may be more or less on other planets or moons than on Earth. • You would weigh about one-sixth of your Earth weight on the moon. • The newton (N) is the SI unit, the pound (lb) is the English unit.

32. Chapter 1 Introduction to Physical Science Volume • Volume is the amount of space an object takes up. • The SI unit of volume is the cubic meter (m3), but we will often measure in Liters (L) or millileters (mL).

33. Volume of a liquid: Graduated cylinder mL Meniscus- curved surface at top of liquid, always record measurements using bottom of meniscus

34. Volume of Rectangular Solid: Volume of Irregular solid: • Example- Cereal box • Volume = Length x Width x Height • Remember to multiply numbers and units, so units will be cubed • Example units: cm3 • Example- Rock • Submerge object in water in graduated cylinder and measure the displacement of the water • Let’s look at the example in your book on page 23 now

35. Density • Two objects of the same size can have very different masses. WHY??? • Because different materials have different densities! • Density is mass per unit volume • So Density = Mass/ Volume • SI unit of density is kg/m3, other common units are g/cm3 and g/mL • Since density is made up of 2 measurements, it always has 2 units

36. Suppose that a metal object has a mass of 57 g and a volume of 21 cm3. Calculate its density. Read and Understand What information are you given? Mass of metal object = 57 g Volume of metal object = 21 cm3 Chapter 1 Introduction to Physical Science Calculating Density

37. Suppose that a metal object has a mass of 57 g and a volume of 21 cm3. Calculate its density. Plan and Solve What quantity are you trying to calculate? The density of the metal object = __ What formula contains the given quantities and the unknown quantity? Density = Mass/Volume Perform the calculation. Density = Mass/Volume= 57g/21cm3 = 2.7 g/cm3 Chapter 1 Introduction to Physical Science Calculating Density

38. Suppose that a metal object has a mass of 57 g and a volume of 21 cm3. Calculate its density. Look Back and Check Does your answer make sense? The answer tells you that the metal object has a density of 2.7 g/cm3. The answer makes sense because it is the same as the density of a known metal–aluminum. Chapter 1 Introduction to Physical Science Calculating Density

39. Practice Problem What is the density of a wood block with a mass of 57 g and a volume of 125 cm3? 0.46 g/cm3 Chapter 1 Introduction to Physical Science Calculating Density

40. Chapter 1 Introduction to Physical Science Density • The density of a substance stays the same no matter how large or small a sample of the substance is. • So a gold earring and a gold necklace will both have a density of 19.3 g/cm3

41. Sink or Float? Problem: Water has a density of 1 g/cm3. Will an object with a density of 0.7 g/cm3 float or sink in water? FLOAT! Knowing an object’s density allows you to predict whether it will sink or float. If the object is less dense than the liquid, it will float. If the object is more dense than the liquid, it will sink.

42. Chapter 1 Introduction to Physical Science Time • The second (s) is the SI unit of time.

43. Chapter 1 Introduction to Physical Science Temperature • Scientists use the Celsius and Kelvin scales to measure temperature. The kelvin (K) is the SI unit of temperature.

44. Chapter 1 Introduction to Physical Science Section 4:Mathematics and Science • What math skills do scientists use in collecting data and making measurements?

45. Estimation: An approximation of a number based on known/ reasonable information Scientists cannot always obtain EXACT numbers Example: measuring distances between stars

46. Accuracy and Reproducibility Accuracy: Reproducibility: How close a group of measurements are to each other Example: Reproducible throws land close to one another • How close a measurement is to the true value • Example: If you were playing darts, accurate throws land close to the bull’s-eye Scientists aim for both accuracy and reproducibility in their measurements.

47. Chapter 1 Introduction to Physical Science Significant Figures • A measurement should contain only those numbers that are significant.

48. Significant figures in a measurement include all of the digits that are known precisely plus one last digit that is estimated. Non-zero digits are always significant. 103.230002 All final zeros after the decimal point are significant. 12.740 ; 0.0420 Zeros between two other significant digits are always significant. 10.0 ; 2004 ; 6.000 Zeros used only for spacing the decimal point are not significant. 100 ; .00000233 Rules to Sig Figs: Here is a handout that discusses these rules….. Let’s look at it now!

49. Adding or Subtracting If you add or subtract, the answer is rounded to the same number of decimal places as the measurement with the least number of decimal places. Example: 5.3 cm (1 decimal place) + 21.94 cm (2 decimal places) 27.24 cm ≈ 27.2 cm (1 decimal place)

50. Chapter 1 Introduction to Physical Science Multiplying and Dividing Measurements • When you multiply or divide measurements, your answers can have only the same number of significant figures as the measurement with the fewest significant figures. 2.25 m X 3 m 6.75 m2 ≈ 7 m2