Bellringer Day In your opinion, what are the five most important lab safety rules?

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1 Bellringer Day In your opinion, what are the five most important lab safety rules?

2 Lab Safety Video

3 Lab Safety Map See if you can identify the lab safety equipment around the room. You can discuss this with the people seated around you.

4 Lab Safety Scenarios Answer the questions below each lab safety scenario. You may work with a partner to complete this. We will discuss it as a group when everyone is finished.

5 Bellringer Day Identify the lab safety symbols below:

6 The Scientific Method

7 What is the Scientific Method? A method of procedure that has been used in science for many years Almost all experiments are carried out using the scientific method!

8 Step 1: Form a Question What is the purpose of the experiment and what do you want to learn? All science starts with a question!!!

9 Let s practice What kind of questions could we form about a plant using the materials shown?

10 Step 2: Research Find out as much about the topic as you can This would be listing what you already know, and taking the time to find out new information

11 What do we already know? What could we research?

12 Step 3: Hypothesis: What do you predict? A hypothesis is an educated prediction about the problem based on the limited information you ve collected They are made before carrying out any experiments

13 Form a hypothesis

14 Step 4: Experiment! Now you are ready to carry out the experiment. In most cases, you would design the experiment yourself In many cases, this will include a control group and an experimental group

15 Control Groups and Variables The control group is used in an experiment as a way to ensure that your experiment actually works.... The experimental group is given the experimental treatment and the control group is given either a standard treatment or nothing. Experimental Group: Independent Variable: the variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable. Dependent Variable: the variable being tested and measured in a scientific experiment.

16 What kind of experiment could we do?

17 Step 5: Analysis Now you record what happened during the experiment. This can be done quantitatively (expressed in numbers, like percentages) and qualitatively (anything outside of numbers) Oftentimes, graphs and charts are used to represent data

18 Analysis: Types of Graphs Bar Graph Line Graph

19 Step 6: Form a Conclusion Finally, you form a conclusion based on what you have observed and recorded Conclusions should be in complete sentences and should always relate back to your hypothesis (does it support it?)

20 Oreo s Lab Activity!

21 Variables Independent Variable: Type of Oreo Weighed Dependent Variable: Weight of the Oreo Control Group: The remaining, untouched Oreos, for comparison

22 Exit Ticket 1. Go to Socrative.com 2. Click on student login 3. Enter the room: XX7CWRJG 4. Enter your first and last name 5. Answer the questions!

23 Exit Ticket Now that you have carried out an experiment, design your own! Choose a food and design an experiment testing something about the food. The experiment does not have to be long, but should follow the steps of the scientific method.

24 Bellringer Day 03 Can you name the following pieces of lab equipment?

25 Bellringer Day 04: Science Trivia 1. What did Edward Binney and Harold Smith invent in 1903? a) Post-it Notes b) Scotch Tape c) Crayola Crayons 2. Which was invented first? a) Telephone b) Microwave Oven c) Light Bulb

26 Bellringer Day Explain how you know that something is moving. 2. What words/units can you think of that describe something in motion?

27 Forces and Motion PHYSICAL SCIENCE: UNIT 1

28 What is Motion? How do you know that an object is in motion?

29 What is Motion? Well, motion is relative! Motion is when a body changes position with respect to a reference point The reference point is the background or object that is used for comparing different positions of an object. Let s take a look

32 Explaining Motion In that example, we see the car as being in motion because we have set the object in the background (the tree) as our frame of reference. The reference point can depend on the type of motion and the position of the observer.

33 Think AbouT it From the reference point of your seat, is your desk in motion? No! From the reference point of space, is your desk in motion? Yes!

34 Bellringer Day 06 Imagine you are sitting on a park bench. Explain how you would know the cars across the street are in motion. You should use the vocabulary from yesterday!

35 Motion Recall that motion is relative to a selected reference point. There are a few important concepts that help us to measure and describe motion. These are: Distance Displacement Speed and Velocity Acceleration

36 Distance vs. Displacement DISTANCE The length of the path an object moves A scalar quantity (only the numerical value, or magnitude) Example units: 5 meters 10 miles 12 kilometers DISPLACEMENT The length of the path an object moves in a particular direction! A vector quantity (both the magnitude and direction) Example units: 5 meters East 10 miles N of E 12 kilometers, 36 degrees West

37 Calculating Distance and Displacement When calculating distance, you will find the total distance traveled, and for displacement the distance from the starting point to the ending point

45 Considering Direction: North, East, Up, and Right are POSITIVE South, West, Down, and Left are NEGATIVE

47 Challenge Question 1. A student walking home from school, point A. They walk to B, to C, and stops at D for a snack. What is the total distance traveled from point A to point D? 2. The student finishes the snack and continues home, ending at point F. What is the total displacement from school to home?

What is the total distance traveled from point A to point D?

48 Challenge Question: Answer 1. A student walking home from school, point A. They walk to B, to C, and stops at D for a snack. What is the total distance traveled from point A to point D? (A to B) + (B to C) + (C to D) = =20 m 1. The student finishes the snack and continues home, ending at point F. What is the total displacement from school to home? Point A to Point F is a total of 8m (10-2). The displacement is 8m.

49 Practice Find: The total distance traveled from A to C Displacement from A to C A 5 B 8 C

50 Practice A brick was moved 5 meters to the right. After that, it was moved 4 meters to the left. What is the total distance the brick moved? What is the displacement?

51 Practice A delivery truck travels 14 blocks north, 16 blocks east, and 26 blocks south. What is the distance traveled? What is the final displacement from the origin?

52 Bellringer Day 07 John travels from point A to point C. What is his total distance traveled? Calculate his displacement?

53 Exploring Motion SPEED, VELOCITY, AND ACCELERATION

Example: 6o miles per hour If you know the distance an object

54 Speed Speed is defined as the rate of motion. It is the distance traveled per unit time. Example: 6o miles per hour If you know the distance an object traveled in a set amount of time, you can calculate the speed of the object. speed (v) (d) distance time (t)

55 Speed is not the only measure to consider. For example A storm is 10 km away and is moving at a speed of 60 km/h. Should you be worried? Answer: It depends on the storms direction! In this instance, we must consider the velocity of the storm

56 Velocity Velocity is speed in a given direction (it is a vector!) Velocity can change even when the speed is constant! (storms!)

57 Comparing Speed and Velocity 1. How are speed and velocity similar? They both measure how fast something is moving. 2. How are speed and velocity different? Velocity includes the direction something is moving. 3. Is velocity more like distance or displacement? Displacement, because both are vectors.

58 Solving for Speed/Velocity #1: Your neighbor skates at a speed of 4 m/s. You can skate 100 m in 20 s. Who skates faster? GIVEN: d = 100 m t = 20 s v =? SOLVE: v = d t v = (100 m) (20 s) v = 5 m/s You skate faster!

59 Solving for Speed/Velocity #2: Sound travels 330 m/s. If a lightning bolt strikes the ground 1 km away from you, how long will it take for you to hear it? GIVEN: v = 330 m/s d = 1km = 1000m t =? SOLVE: t = d v t = (1000 m) (330 m/s) t = 3.03 s

60 Graphing Motion: Speed Slope = speed Steeper slope = faster speed Straight line = constant speed Flat line = no motion

61 Graphing Motion: Speed 1. Who started out faster? A (steeper slope) 2. Who had a constant speed? A 3. Describe B from min. B stopped moving 4. Find their average speeds. A = (2400m) (30min) A = 80 m/min B = (1200m) (30min) B = 40 m/min

62 Bellringer Day 08 How far can you get away from your little brother during a game of paintball if you can travel at 3 m/s and you have 15s before he sees you? Hint: Use your formula triangle!

63 Acceleration Acceleration is the rate at which velocity changes It can be a change in speed or direction. Positive acceleration=speeding up; negative=slowing down We use a formula very similar to speed/velocity to calculate the acceleration. a v f v i t

64 Solving for Acceleration #1: A roller coaster starts down a hill at 10 m/s. Three seconds later, its speed is 32 m/s. What is the roller coaster s acceleration? GIVEN: vi = 10 m/s vf = 32 m/s t = 3s a =? SOLVE: a = (vf - vi) t a = (32m/s - 10m/s) (3s) a = 22 m/s 3 s a = 7.3 m/s2

65 Solving for Acceleration #2: How long will it take a car traveling 30 m/s to come to a stop if its acceleration is -3 m/s2? GIVEN: t =? vi = 30 m/s vf = 0 m/s a = -3 m/s 2 SOLVE: t = (vf - vi) a t = (0m/s-30m/s) (-3m/s 2 ) t = -30 m/s -3m/s 2 t = 10 s

66 Graphing Motion: Acceleration

67 Bellringer Day 09 A car is traveling at a constant speed of 12 m/s. When the driver accelerates, the car reaches a speed of 26 m/s in 6 s. What is the average acceleration of the car? Hint: Use your formula triangle!

68 Exploring Motion MOMENTUM

69 Momentum Momentum is a property of a moving object that makes it hard to stop. The more mass it has or the faster it s moving, the greater its momentum. Momentum equals mass times velocity and is represented by the equation: Momentum (p) = Mass (m) Velocity (v)

70 Exploring Momentum Momentum is a relationship between mass and velocity. A slow-moving, massive object may have the same momentum as a very small, high speed object! Ex. A 100 kg object moving 1 m/s has the same momentum as a 1-kg object moving 100m/s!

Examples of Momentum Any object with momentum is going to be hard to stop.

71 Examples of Momentum Any object with momentum is going to be hard to stop. To stop an object with momentum, force must be applied against its motion for a given period of time! This is known as impulse. Examples of impulse/momentum relationship: Airbags in Cars: The force of the airbag stops the passengers momentum to minimize injury. Sports: In football, the defensive players apply a force for a given amount of time to stop the momentum of the offensive player who has the ball. Jumping: Bending your knees when landing increases the stopping time, thus decreasing the force with which you land.

72 Bellringer Day 10 Explain the term momentum and provide a real life example. Try to come up with one different from those we discussed yesterday!

73 Exploring Motion GRAVITATIONAL FORCES AND FREE FALL

74 Gravity Gravity is the force of attraction between any two objects in the universe Gravity increases as Mass increases Distance decreases

A look AT GrAviTy WHO EXPERIENCES MORE G

75 A look AT GrAviTy WHO EXPERIENCES MORE G R AVITY, T H E MAN O N E A R T H O R T HE A S T R O N A UT? W H Y? WHICH EXERTS MORE G R AVITY, T HE EARTH O R T HE MOON? WHY? The man, because he is closer to Earth. (gravity increases as distance decreases) The Earth, because it is heavier. (gravity increases as mass increases)

76 Gravity and Weight The weight of an object is dependent on gravity. Weight is the force of gravity on an object. It is important to understand that mass is always the same, while weight depends on gravity! W = mg W: weight (N) m: mass (kg) g: acceleration due to gravity (m/s 2 ) On Earth: g = 9.8 m/s 2

77 Gravity and Weight You weigh more on Jupiter because Jupiter has a greater mass than Earth, and therefore greater gravity!

78 Air Resistance Air Resistance is the force that air exerts on a moving object to oppose its motion. Depends on: speed, surface area, shape, density of fluid

Terminal Velocity Terminal velocity is the maximum velocity reached by a falling object With air resistance, heavier objects fall faster because

79 Terminal Velocity Terminal velocity is the maximum velocity reached by a falling object With air resistance, heavier objects fall faster because they accelerate to higher speeds before reaching terminal velocity In the absence of air resistance, all falling objects have the same acceleration!

80 Gravity Formulas Remember, the weight of an object is a measure of the force of gravity and is the product of its mass and the acceleration due to gravity. F g = mg Fg:Force (N) m: mass (kg) g: acceleration due to gravity (m/s 2 )

81 Solving for Gravitational Force #1:A 3000kg plane has an acceleration of 12 m/s 2 on takeoff. What net force is exerted on the plane? GIVEN: g=12 m/s 2 m= 3000 kg F g =? SOLVE: F g = m x g (acceleration) F g = (3000) x (12) F g =36,000 N

82 Solving for Gravitational Force #2: Ms. F. weighs 557 N. What is her mass? GIVEN: g=9.8 m/s 2 (the constant gravity on Earth) m=? F g = 557 N SOLVE: m = F g g m = m = 56.8 kg

83 Bellringer Day Where would you weigh more-pluto or Earth? Why? 2. What would happen to falling objects if there was no air resistance?

84 Exploring Motion FRICTION

85 Friction Friction is a force that opposes motion of an object There are numerous types of friction that may be present in a situation

86 Static Friction Static Friction: Friction that exists between a stationary object and the surface on which it s sitting Example: A book resting on a table

87 Sliding Friction Sliding Friction: A type of frictional motion between two surfaces in contact Example: A box pushed across the floor

88 Rolling Friction Rolling Friction: The force resisting the motion when a body rolls on a surface Example: A ball rolling across the floor

89 Fluid Friction Fluid Friction: The force that resists the movement of a solid object through a fluid (liquid or gas) Examples: A boat moving through a river; an object in freefall

90 Bellringer Day 12 Choose and define (2) types of friction we discussed yesterday and provide real world examples of each. Try to come up with examples different from those we discussed in class together!

91 Exp ring M i n NEWTON S LAWS OF MOTION

92 newton s laws of motion Newton s 3 laws of motion are physical laws that have been tested and verified, and apply to the physics of most motion All of the concepts we have discussed with motion so far can be applied to one of Newton s 3 laws!

93 newton s laws of motion An object at rest will remain at rest and an object in motion will remain in motion until acted upon by a net force 1 st Law 2 nd Law When an object exerts force on a another, the The force acting on an object is equal to the mass of that object times its acceleration 2nd one exerts a force on the 1st equal in strength and opposite in direction 3 rd Law

94 newton s 1 st Law of Motion An object at rest will remain at rest and an object in motion will continue moving at a constant velocity unless acted upon by a net force. If a change in motion of an object is observed, there must have been a net force on the object.

95 newton s 2 nd Law of Motion The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. You should become very familiar with this formula-it is one of the most important in physics!

96 newton s 2 nd Law #1: What net force is required to accelerate a car at a rate of 2 m/s 2 if the car has a mass of 3,000 kg? GIVEN: F=? m = 3,000 kg a = 2 m/s 2 SOLVE: F = m x a F = 3,000 x 2 a = 6,ooo N

97 newton s 2 nd Law #2: What is the mass of a falling rock if it produces a force of 147 N? GIVEN: a = 9.8 m/s2 (acceleration due to gravity) F = 147 N m =? SOLVE: m = F a m = m = 15 kg

98 newton s 3 rd Law of Motion When one object exerts force on a second object, the second one exerts a force on the first that is equal in strength and opposite in direction They are equal and opposite, but they do not cancel since they are not applied on the same body. Example: A block sitting on a table. The action force is applied by the block on the table, and the reaction force is applied by the table on the block. They do not cancel.

99 Bellringer Day A 100 kg student kicks a 1.5kg ball with a force of 450N. What force does the ball apply on the student? 2. Which of Newton s Laws is represented in the above problem?

100 Bellringer Day 14 A student applies a force to a box with a mass of 30 kg. If the student applies the same force to a box with a mass of 15 kg, which best describes the effect on the acceleration of the 15-kg box? a) It is half the acceleration of the 30-kg box. b) It is double the acceleration of the 30-kg box. c) It is the same as the acceleration of the 30-kg box. d) It is triple the acceleration of the 30-kg box.

101 Bellringer Day 15 Give an example of a scalar quantity vs. a vector quantity.

102 Bellringer Day 16 Newton s Law Review: 1. Which law describes the relationship between mass, force, and acceleration? 2. One body exerting a force equal and opposite another body is which law? 3. Write the formula for Newton s 2 nd law.

103 Egg Drop!

104 Bellringer Day 17 Describe the motions of the graphs below (no motion, constant speed, or acceleration)

105 Day 18: Test Day Take a few minutes to study! Be sure your binders are in order for binder check!

Newton s Laws of Motion

Motion & Forces Newton s Laws of Motion If I have seen far, it is because I have stood on the shoulders of giants. - Sir Isaac Newton (referring to Galileo) A. Newton s First Law Newton s First Law of