€¦ · web viewin a previous lesson we utilized newton's first law of motion to predict...

Additional Resources (U1L2) Pulleys ModuleReading StrategiesThese reading tools will help students learn the material in this unit: Science Terms, Describing Space and Time, and Foldable.

Key Term Foldable, the key-term foldable can help students learn key terms form this lesson. A key-term fold may be useful for studying definitions of key terms in this lesson. Each tab can contain a key term on one side and its definition on the other. Have students use the key-term fold to quiz their self on the definitions of the key terms in the lesson. Students should fold a sheet of lined notebook paper in half from left to right. Using scissors, cut along every third line from the right edge of the paper to the center fold to make tabs. Have students write one key term from the lesson page on the front of each tab. As students are introduced to vocabulary, have them write the definition for each term under its tab. Students can then use this foldable to study the key terms.

Cause and Effect, certain words or phrases can serve as signals of cause and effect relationships. Such signals are called cause and effect markers.

As students’ progress through the lesson have them complete a cause and effects markers table, similar to the one shown, with the cause and effect markers that are in this lesson.

Two-Column Notes, Two-column notes can help students learn the key ideas from each activity. The key ideas are listed in the left column while the right column is completed with the students own words. Students should write detailed notes and examples in the right column. As students participate in each activity have them complete a two-column notes for each activity, adding another row for each key idea.

Bell Ringers/Warm-up Exercises1. Mark Up The Text (MUTT) – Energy Transformations Have students answer the following questions

on their Journal or Daily Lesson Log once they have completed MUTTing the article: What did you learn from the article? What is one fact that surprised you from the article? What is one question you have after reading the article?

2. Hash Tag, Vocabulary/Reading Strategy, Have students complete the Hash Tag chart for the concepts of Friction, Mechanical Energy, and Conservation of Work. This graphic organizer will help students brainstorm all they know about the concepts covered in the lesson. Once students have

Version 04.15.19 © 2019 Purdue University All Rights Reserved Page | 1

completed their chart as their warmup activity, go around the room and have students provide one of their Hash Tags. Have students vote on the Hash Tag most likely to trend and award that student extra credit or some other award.

3. Mark Up The Text (MUTT) – Pulleys and Conservation of Work, Have students MUTT the Building the Conservation of Work Testing Apparatus section of the pulleys experiment in preparation of making their testing apparatus. Have students answer the following questions on their lesson log once they have completed MUTTing the article: What are you going to build? What tools will you need to build your device? How does your device work?

4. Pulleys Background Information Quiz, Establish 4-5 questions that will gauge whether students have read, and understand, the material in the background section of the Lever Investigation activity. This can be handed out as students enter the classroom or in a more formal manner after class has begun. You may choose to use the following: What is one advantage of a pulley? What are the three requirements for work to take place? What is friction? What is the formula for calculating tension? What is the equation for determining the friction coefficient?

5. ABC Chart, Vocabulary/Reading Strategy, Have students complete the ABC Chart for the terms; Energy, Work, Mechanical Advantage. This graphic organizer will help students brainstorm all they know about the term. Students complete the chart by writing a term or short phrase that starts with each letter of the alphabet. Once students have completed the chart as their warmup activity, go around the room and have students provide the term they used for a specific letter in the alphabet. Try to complete an ABC Chart from classroom participation.

6. Word Web, Vocabulary/Reading Strategy – Pulleys, Have students create a Word Web for the term Pulleys. Students should include all the information they can recall from the past lessons to create connections between concepts, equations, and experimental data.

PowerPoint Slide Show PresentationsThe following presentation resources are available on the Hardware Stores Science website hardwarestorescience.org

PowerPoint Slide Show Presentation, Work, This slideshow covers the fundamentals of Work. It is geared towards the simplest forms of work, where the direction of force is perpendicular or parallel to the motion of the object. This way students are able to learn the concept of work without the added confusion of vectors and the use of complex math. Explain to students that work is a combination of force, displacement and cause. Ensure students understand that these three conditions must be met in order for work to take place. Explain that work can be done against another force (i.e. gravity) or to change motion (i.e. speed). Ensure students understand the difference between work input and work output as well as the input force and the output force.

PowerPoint Slide Show Presentation, Simple Machines, Use this slide show to review with students the concept of simple machines and mechanical advantage. Pay particular attention to the forces involved and student understanding of those forces. Ensure students are familiar with the types of simple machines and in determining the work input and output. When discussing how to calculate work and mechanical advantage, ensure students understand how to properly manipulate mathematical equations.

PowerPoint Slide Show Presentation, Mechanical Energy, Use this slide show to review with students the concept of Mechanical Energy and introduce Potential and Kinetic energy. Pay particular attention to the equations for determine potential and kinetic energy. Ensure students are familiar with the types of potential energy. When discussing how to calculate mechanical, potential and kinetic energy, ensure students understand how to properly manipulate mathematical equations.


Printable ResourcesThe following resources are found in the Appendix.

Daily Lesson LogHash Tag ChartABC Chart

Online ResourcesThe following resources are found online, and can be accessed through their individual websites or in a word document version at the Hardware Store Science website. One advantage of using the word document version of this article is that educators are able to download and edit the document with questions, writing prompts or other student suggestions.

Energy Transformation? – This article was on the University of Calgary Website, last updated July 21,, 2018. It can be found at https://energyeducation.ca/encyclopedia/Energy_transformations or a word document of this article, without the ads and other distractors, can be found at hardwarestorescience.org

Background Information: PulleysPulleys can be very complicated. Engineers combine multiple pulleys into a pulley system that significantly reduces the amount of force required to lift an object. Laborers often use pulley systems to move extremely heavy objects. With a block and tackle pulley system they take a lot of cable or rope to lift several tons. Engineers take advantage of block and tackle principles with motors and electronics to create devices that operate with very low power requirements, such as cranes and elevators.

Engineers are experts at exploiting the advantages of simple machines in all sorts of real-world applications that benefit society. One way in which they do this is by incorporating the mechanical advantage of pulleys into their design of many modern-day structures, machines, products and tools. Using multiple pulleys in conjunction with motors and electronics, engineers create complex modern devices that perform work for very little power.

A pulley is a simple machine consisting of a string (or rope) wrapped around a wheel (sometimes with a groove) with one end of the string attached to an object and the other end attached to a person or a motor. Pulleys act just like levers in that they have an input force, and output force, and a pivot point. The main difference is that the lever arm of a pulley rotates all the way around the fulcrum. Pulleys have the ability to provide a powerful mechanical advantage, so lifting tasks may be done easily.

One advantage of a pulley is that it changes the direction of the force used to lift an object. Is it easier to pull up on a rope or pull down on a rope? By using a pulley, we do not have to pull up on a rope to lift a heavy object attached to it, but instead we can pull down on it. When you pull down on the rope of a flagpole, the flag goes up the pole to wave in the air. The flagpole’s pulley redirects your input force into an output force of raising the flag.


Another advantage of a pulley lies in the use of multiple pulleys at once. This decreases the amount of force necessary to move an object by increasing the amount of rope used to raise the object. The mechanical advantage (MA) of a pulley system is equal to the number of ropes supporting the movable load.

MA= load¿of rope sections

To gain this greater mechanical advantage, there is a trade-off. So, if two pulleys are used together, the amount of force required is cut in half, but twice the amount of rope is pulled to raise the object to the same desired height.

The most commonly understood concept of a pulley is that it is a simple machine that redirects force. This means that by looping rope around a pulley and attaching the rope to an object, pulling down on the other end of the rope will raise the object, instead of having to lift the object. Although this is a helpful and convenient use for pulleys, it has a major limitation: the force you must apply to lift the object is the same amount as if you were just lifting the object without the pulley. This means that a fixed pulley does not give any mechanical advantage.

A fixed pulley configuration is useful for raising an object to a level above your head. Using this type of pulley also enables you to take advantage of gravity. And, by attaching weights to the end of the rope that you pull, you can lessen the amount of force you must apply. This type of pulley can also be used to balance an object, by attaching objects of equal weight to both sides of the rope, neither object moves. Once a force is applied to either side, the system continues moving in that direction. This kind of pulley system is used in some elevators. The elevator has cable attached to it that goes up, around a pulley, then comes down and attaches to a counterweight. The motor that moves the elevator car uses much less power since the counterweight keeps the elevator balanced.

Another type of pulley is a movable pulley. In a movable pulley system, the rope is attached to a fixed (non-moving) point, the pulley is attached to the object that you want to move and the other end of the rope is left free (see Figure 6). By pulling on the rope, the pulley moves and the object raises. This type of system is good if you are trying to raise an object located below you to your level

Using a system of pulleys can be much more complex and provide a powerful mechanical advantage — greatly reducing the amount of force required to move an object. If one movable pulley is used, the amount of force required to raise the object attached to the movable pulley is cut in half. The trade-off, as discussed earlier, is that the amount of rope required increases and the amount of rope that you must pull to raise the object is also increased.

ForceA force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. When


the interaction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction.

For simplicity sake, all forces (interactions) between objects can be placed into two broad categories: contact forces, and forces resulting from action-at-a-distance

Contact forces are those types of forces that result when the two interacting objects are physically contacting each other. Examples of contact forces include frictional forces, tensional forces, normal forces, air resistance forces, and applied forces.

Action-at-a-distance forces are those types of forces that result even when the two interacting objects are not in physical contact with each other, yet are able to exert a push or pull despite their physical separation. Examples of action-at-a-distance forces include gravitational forces, Electric forces and magnetic forces. The sun and planets exert a gravitational pull on each other despite their large spatial separation. Even when your feet leave the earth and you are no longer in physical contact with the earth, there is a gravitational pull between you and the Earth. The protons in the nucleus of an atom and the electrons outside the nucleus experience an electrical pull towards each other despite their small spatial separation. Two magnets can exert a magnetic pull on each other even when separated by a distance of a few centimeters.

In a previous lesson we utilized Newton's first law of motion to predict what happens to objects when they are in equilibrium. Equilibrium is the condition in which all forces acting on an object are balanced and will not change their motion, i.e. accelerate. According to this idea, an object will only accelerate if there is a net or unbalanced force acting upon it.

Newton's second law of motion is focused on the behavior of objects for which the existing forces are not balanced. This law states that the acceleration of an object is dependent upon the net force acting upon the object and the mass of the object. As the force acting upon an object is increased, the acceleration of the object is increased. As the mass of an object is increased, the acceleration of the object is decreased.

Newton’s second law can be expressed in equation form as

a=Fnetm

This equation is often rearranged to a more familiar form

Fnet=m×a

By substituting standard metric units for force, mass, and acceleration into the above equation, the following unit equivalency can be written.

1Newton=1kg ∙m / s2

Thus, the definition of the standard metric unit of force is a Newton and is defined as the amount of force required to give a 1-kg mass an acceleration of 1 m/s/s.


Newton's second law provides the explanation for the behavior of objects upon which the forces do not balance. This law can be understood to be saying that acceleration is directly proportional to the sum of all forces acting on an object and inversely proportional to the mass of the object.

If mass (m) and acceleration (a) are known, then the net force (Fnet) can be determined by use of the equation.

Fnet=ma

If the net force value and the direction of that force is known, then the value of the individual forces can be determined. Students can use their understanding of weight and mass to find the m or the Fgrav in a problem. They can use their conceptual understanding of net force (vector sum of all the forces) to find the value of Fnet or the value of an individual force.

If either all the vertical forces (up and down) do not cancel each other and/or all horizontal forces do not cancel each other, then an unbalanced force exists. This unbalanced force gives rise to the motion of an object.

It is commonly said that in each situation there is a net force acting upon the object. The net force is the “vector sum” of all the forces that act upon an object. All forces are a combination of magnitude and direction (vector). That means the net force is the sum of all the forces and that any two forces of equal magnitude and opposite direction will cancel each other out. This can be explained with a simple illustration. Observe the following examples of summing two forces: FrictionThe friction force is the force exerted by a surface as an object moves across it or makes an effort to move across it. Though it is not always the case, the friction force often opposes the motion of an object. For example, if a book slides across the surface of a desk, then the desk exerts a friction force in the opposite direction of its motion. Friction results from the two surfaces being pressed together closely, causing interaction between the two different surfaces. As such, friction depends upon the nature of the two surfaces and upon the degree to which they are pressed together.

The force of static friction, is a force between two surfaces that prevents those surfaces from moving across each other. The magnitude of static friction determines how easily an object will slide. When two surfaces are sliding past each other, the frictional force always opposes the sliding motion and tries to reduce the speed at which the surfaces slide across each other. This sliding friction is called kinetic frictional force, a frictional force relating to or resulting from motion.

For example, a person sliding into second base during a baseball game is using the force of kinetic friction to slow down. If there were no kinetic friction, the baseball player would just continue sliding. If there were absolutely no friction between your feet and the ground, you would be unable to propel yourself forward when you were running, and would simply end up jogging in place (similar to trying to run on very slippery ice).

Static FrictionRegarding friction and driving automobiles, the existence of static friction is actually the reason vehicles move at all. When a tire spins, if there were no friction then as the tire spins the tire surface and the


road surface would slip past each other. The tire would not grip the road. However, due to static friction there will be no motion between the tire and the road at the point of contact, meaning that as the axle spins the force is translated into motion of the car rather than simply the wheel spinning in place.

The static friction force experienced by an object is given by the formula:

F static≤μstatic× Fnorm (1)

where Fstatic is the static friction force, µstatic (where the Greek letter is pronounced “mew”) is the static friction coefficient, and Fnorm is the normal force pushing the two objects together. On a surface parallel with the earth, Fnorm is equal to the object’s weight. The less than or equal to symbol is used because this force will grow as the applied force grows. For two objects in contact, if there are no applied forces tangential to the surface, then Fstatic equals zero. If the applied force is 1 N, then Fstatic equals 1 N (assuming that this is less than or equal to the product µstatic x Fnorm). This means that the object remains stationary. However, there is an upper limit to the static friction force, which is reached when the formula above becomes an equality. For applied forces above this value, the object will experience a net force and begin to move.

Given this formula, we return to static friction and automobiles. If a vehicle is at rest relative to the road, a small applied force by the spinning of the axle will not overcome the quantity µstatic x Fnorm, such that the tire will not slip on the pavement, as we mentioned before. However, if the driver were at a stop and then put the pedal to the metal, there would be a very high force, which would overcome the maximum static friction force. In this case the tires will spin on the road without gripping it, causing smoke to be released and preventing the vehicle from moving anywhere.

Kinetic FrictionIn addition to static friction, we also discuss kinetic friction. When the surfaces of two objects are in contact and they are experiencing relative motion, kinetic friction acts to resist this motion. The magnitude of the friction force is given by the equation:

F kinetic=μkinetic×Fnorm (2)

where Fkinetic is the kinetic friction force, µkinetic is the kinetic friction coefficient, and Fnorm is again the normal force pushing the two objects together. This equation shows that the friction force is always the same between two objects, not varying with applied force as the static friction force did. Interestingly, this equation means that the kinetic friction force does not depend on the speed of the object. A fast moving object experiences the same kinetic friction force as a slow moving object (although fluid drag forces will differ). Furthermore, the kinetic friction force depends on the normal force (the weight for a horizontal surface), but it does not depend on the contact area of the surfaces. This means that two objects of the same material and the same weight will experience the same kinetic friction force even if one has a large contact surface and the other has a small contact surface. This result is sometimes counterintuitive. One explanation is that for a given weight, the smaller surface will be pressed down with more force per unit area, meaning that there will be more microscopic hills and valleys in contact with the opposing surface. Thus over the entire surface area for both objects, the number of hills and valleys in contact will be the same.

Kinetic friction is quite important in the automotive industry. Disc brakes use this sliding force as the primary means to brake vehicles. When the brake pedal is pressed, the brake pads on the disc brakes begin squeezing against the rotating wheels. When the brake pedal is pressed harder, the brake pads squeeze harder, meaning that Fnorm increases and the kinetic friction force increases, slowing the vehicle


faster. Brake pads are made of materials with high values of µkinetic meaning that larger friction forces can be applied.

The following experiment will determine the friction coefficients between two surfaces, and it can also be used to verify that speed and contact area do not affect the frictional forces between two objects.

For any two surfaces in contact, the kinetic friction coefficient is generally less than the static friction coefficient. Values for the kinetic friction coefficient, µkinetic are usually between 0.2 and 0.6 for various metal interactions. When Teflon is one of the materials µkinetic can be below 0.1. Rubber on dry asphalt can be as high as 0.8. Values for the static friction coefficient, µstatic typically range from 0.5 to 1.0, with Teflon again falling below 0.1. Rubber in contact with asphalt can be as high as 0.9.

Hardware Store Science and MakingTo effectively teach science, teachers need resources — and usually a lot of resources like; specialized equipment, tools, and supplies not to mention resources for projects, models, and demonstrations. These things don’t come cheap. That means teachers often have to spend a significant amount of time altering lesson plans to accommodate resources. The era of open-source software and cheap hardware, including 3-D printers, is making it easier for teachers to provide the resources students need to do some forms of scientific investigations. Still the costs of these technologies typically limit their inclusion to the dominion of more affluent schools. As a result many teachers have begun to embrace the build-it-yourself mentality to provide their students with a variety of learning opportunities for such topics as energy, motion, and forces. These “maker” skills and mentality have to potential of transforming the science classroom into a unique learning environment.

In the hands of students, maker skills and tools can help transform abstract concepts into tangible objects, especially those students and classrooms who need a piece of equipment that doesn’t exist or is too expensive to purchase using available funds.

Maker Pedagogy has been defined as “an approach that utilizes the principles of ethical hacking (i.e., deconstructing existing technology for the purpose of creating knowledge), adapting (i.e., the freedom to use a technology for new purposes), designing (i.e., selecting components and ideas to solve problems), and creating (i.e., archiving contextual knowledge obtained through engaging in the process of making, as well as the actual tangible products) as part of an overall way of working with those interested in learning about science and technology.”

Many students are clueless when it comes to “making” and using hand tools. As such it will become import for you to monitor students on use and safety of hand tools and “making” processes, even after students have successfully met all requirements for using hand tools in your classroom or “Maker Space.”

Knowing how to handle tools is an essential skill everyone should have the ability to do correctly. Students will become more self-reliant, your supply budget money will stretch further, and students will develop a more in-depth knowledge of the concepts they are exploring when they are required to “make” their own experimental apparatus.

How to Use a HandsawBefore students put saw to wood, they need to determine what sort of handsaw they will need for the job. There are two basic designs of handsaws: the crosscut saw and the rip saw. Which one you use


depends on whether you plan on cutting with or against the wood grain. Let’s take a closer look at the differences between the two saws and when you would use them.

Crosscut saw. If you’re cutting across the grain of the wood, you’ll want to use a crosscut saw. The teeth on a crosscut saw angle back and have a beveled edge. The teeth are also much smaller than those on a ripsaw. This design allows the saw to act like a knife-edge that cleanly slices through the wood’s grain. The crosscut saw’s design also allows the saw to cut on both the push and pull stroke.

Rip saw. When you’re making a cut parallel to the direction of the grain of the wood, use a ripsaw. Unlike a crosscut saw, the teeth on a ripsaw don’t angle backwards nor are they beveled. Instead, the teeth bend left and right in an alternating pattern. This design allows each tooth to act like a chisel that chips away small pieces of wood on each push stroke. The chisel design ensures a clean cut as you saw along the grain. Also, unlike the crosscut saw, the rip saw only cuts on the push stroke, not on the pull stroke.

Typically, carpenters and woodworkers follow a few simple guidelines when using a hand saw.

Mark the cutline. Remember the timeless rule of carpentry: measure twice, cut once. Students should measure where they want a cut (twice of course) and draw a line marking where they want the cut to be. The line will act as a guide to help them get a straight cut.

Make the starting cut. When students make the first cut, have them use their thumb or the knuckle of their thumb on the hand holding the wood as a guide to ensure they cut along the cutline.

If they are using a crosscut saw, have them start their cut with the teeth nearest the handle. This will give them the best control. Make a few back cuts until they get a nice kerf (opening in the wood).

If they are using a ripsaw, have them start their cut with the finer teeth furthest from the handle (near the point of the blade). Make a few short draw strokes to get a kerf going.

Remind students to not start the cut right on the line they marked earlier with pencil. Instead, cut right next to the line on the waste side, or side they don’t want. It’s always better to have a piece of wood that’s a bit long, than a bit short. They can always sand the wood down to the pencil line if more precision is needed.

Angle the saw correctly. After they get their kerf going, students need to angle their saw correctly to get the best cut. This is typically between 45 and 60 degrees to the cutting surface. Some carpenters and woodworkers go so far as to break it down as


follows: for crosscut saws, the proper angle is 45 degrees between the saw and wood and with ripsaws, it’s 60 degrees.

Hold your elbows close to your body. To counteract the natural tendency to angle the blade away from perpendicular, have students hold their elbows close to their body when sawing. This will also help them prevent a twisting and tilting the blade, thus ensuring a nice, clean cut.

How to hold the saw. Students should grip the handle so that their forefinger extends along the side of the handle. This will help them “point” the saw along the line and ensures more accurate cuts. They should also hold on to the handle firmly, but not too tightly.

The stroke. After students have started the groove, a few short forward strokes will deepen the cut so they can move the hand they used as a guide away from the blade. Students will then be able to push the saw with an easy, free-running motion. Remind them to use long strokes so that each tooth does a fair share of the work. Short strokes can dull the saw and make it harder to cut.

Students should resist the temptation to bear down on the saw. It won’t do anything except tire them out. Let the saw do the work. If they feel like the saw isn’t cutting properly, the saw may be binding or it may be dull and in need of sharpening.

For straight cuts, use a guide. For some students, simply using the pencil line as their guide to cutting just doesn’t work. If students want to ensure that they get a true and square cut, have them place a small board, as a guide, along the pencil line and clamp it to the board they are cutting. The board will now act as their guide to keep the saw on the line. If available, a miter box can be another effective means of ensuring an accurate cut

Correcting veering. Even the best carpenters and woodworkers veer from the cut line occasionally. If this happens to students, tell them to avoid the natural tendency to twist and bend the saw blade so it gets back on track. This will only result in an uneven and rough cut. Instead, have students stop sawing and bring their blade back to the point where they veered off and start sawing again on the line.

Prevent binding. The biggest problem students will encounter, especially when they are cutting along the grain with a rip saw, is binding. Binding occurs when the kerf closes in on the saw. To prevent this, have students place a nail in their kerf. This will keep it open. Remind students that they may need to move the nail towards them as they saw.

Cordless Drill/Driver BasicsA cordless drill can handle all the drilling and driving needs of your students. A cordless drill gives students all the benefits of a drill without the hassle of a power cord or the fatigue associated with a hand held screwdriver.

A cordless drill typically comes with a battery and a charger, and some kits including a spare battery. For drills with lithium-ion batteries, you can keep a battery on the charger at all times so they will be ready whenever you have a project you want your students to complete. For other battery types, only charge the batteries as needed — this will help you get the longest life from your batteries.

A cordless drill also has forward and reverse settings with most having a variable speed trigger – the more pressure you put on the trigger, the faster the bit spins. There is also a high and low torque setting switch on top of the drill — higher speeds, low torque, are for drilling while lower speeds, high


torque, are for driving. Most drills also have an adjustable clutch that gives you even more control over torque and helps you prevent overdriving.

The chuck of the drill is the piece that holds the bits in place. Most drills have a 3/8-inch chuck and can handle bits and accessories with a shank — the portion of the bit the chuck secures — 3/8 inch or smaller. Some larger bits have a reduced shank for use on smaller drills. Any task students are required to complete along with this curriculum will not require a bit with a shank larger than 3/8 inch.

If students have access to a 20 to 40-piece drilling and driving accessory kit, they will have everything you need to do all projects, challenges, and investigations associated with this curriculum.

Create a pilot hole. When driving screws into wood, it’s a good idea to drill a pilot hole first. Without pilot holes, screws tend to follow the grain of the wood, which results in crooked screws. Thus, pilot holes ensure that students drive the screw in straight.

Pilot holes also help prevent the wood from splinting as they drive the screw in. For small screws a pilot hole can be made with a small diameter drill bit. For larger sized screws and all screws in hardwood, drill a pilot hole using a drill bit with a counter sinking ability.

1. To drill a pilot hole, have students select a drill bit that is a little smaller than the tip of the screw.

2. They will insert a bit into your drill. 3. Have students hold their hand firmly around the chuck of the drill, and keeping it still while

running the drill in reverse, (#1 below) open the chuck (#2) or run the drill forward to close the chuck (#3).

4. When the chuck opening is big enough, have students insert the bit or driver. Remind students to not allow the bit or driver to fall to far into the chuck opening.

5. Have students hold their hand firmly around the chuck of the drill as they did before and run the drill in the forward motion until the bit is secured in the drill (#4).

6. Students should place the tip of the bit on the desired location for the pilot hole and ensure that the drill is straight and true with respect to the board orientation.


7. While pulling firmly on the trigger, students will use a firm and steady motion, to create their pilot hole. There should be little pressure required to drill a vertical pilot hole within a board because the weight of the drill will do most, if not all of the work. Horizontal holes will require a firm pressure while maintaining correct orientation with the board.

After students have drilled their pilot hole(s) they will attach their screwdriver bit and drive the screw in. Attachment of the screwdriver bit, and driving their screw, is accomplished the same way as inserting a drill bit and drilling a pilot hole.

Driving a screw with a screwdriver. Place the screw on the driver tip and hold both screw and tip together with the fingers of one hand. Align the screw tip with the pilot hole drilled previously and apply very little pressure on the driver while turning in a clockwise direction until the screw engages the wood.

When the screw’s thread engages with the wood, move fingers that were holding the screw in place to the screwdriver shank. Use these fingers as a guide to hold the tip directly in line with the screw. Apply enough pressure on the driver to keep it engaged with the screw.

Screwdrivers only do one job: drive and draw screws. No matter how much care you take with your screwdrivers, they’re bound to get worn or chipped. If you notice your screwdriver’s tip getting a bit rounded or chipped, avoid using it. You risk the screwdriver slipping from the screw and injuring your students.

You may be asking, “Can’t my student just use a cordless drill/driver to drive screws, without the hassle of pilot holes?” Indeed you can. However, be careful when doing this as they often provide more torque and power than you need, which, if you’re not careful, can result in stripping the screw and causing injury to the hand and other nearby objects. Using a pilot hole prevents these sorts of things because the screw will drive more easily and run true to the pilot hole.

When you are driving a screw, you will want to use a screwdriver bit in the end of your drill that matches the type of screw you are driving. Most likely, you will need to use a Phillip’s head drill bit but you may also choose square head and star (torx) head screws.

Some screwdriver bits come with a guide for holding screws in alignment with the bit. When using this type of driver bit, students will pull the sleeve over the screw to help keep it stable while they are driving the screw. The cover moves itself back as the screw goes into the surface. A screw guide isn’t necessary, but is extremely helpful with getting screws in straight and not having the screw fall off the bit.

How to read a Tape MeasureWhen it comes to building and craftsmanship, taking accurate measurements can be the difference between a great finished product and a subpar one. Luckily, with the proper approach, using a tape measure can be a quick, easy way to get you the information you need about your project. Knowing how


to use and read a retractable measure and a traditional ribbon-style tape measure can be a major asset to anyone working with his or her hands.

1. Use the big, numbered markings for inches. On a tape measure labeled with standard units, the most prominent marks are usually the one-inch marks. These are typically marked by long, thin lines and fairly large numbers.

Every 12 inches, there will often (but not always) be a foot marking. This is usually in a different color than the other markings — often red in contrast to the normal black markings. The numbers next to each inch mark will keep a continuous count while the foot markings may be followed by a repeat from 1 - 11. This can vary from tape measure to tape measure.

Note that the line next to the number marks each inch, not the number itself.

2. Use the bigger marks between two inch markings for half-inches. A half-inch mark is always centered between any two one-inch marks. It almost always has the second-longest marking (after the one-inch marks). There will be one half-inch mark between each one-inch mark, but it is important to remember that there are two half-inches per inch.

Note that, starting with half-inch marks, not all lines may be labeled with numbers. In this case, students will need to use the markings on either side to guide them. For example, the half-inch mark between inches three and four stands for 3 1/2 inches, even though it's not labeled.

3. Use the smaller lines between half-inches for quarter-inches. These markings are smaller than half-inches but usually bigger than the 1/8 and 1/16 inch marks around them. They are evenly spaced between each half-inch mark and one inch-mark. There are four quarter-inches in one inch.

Note that lines marking a quarter of an inch sometimes aren't any different in size from eighth-inch marks. In this case, students will need to remember that two eighths of an inch make a quarter.

4. The next smaller marks are for one-eighth-inches. These markings are centered between the inch marking and the quarter-inch marking, the quarter-inch marking and the half-inch marking, and so on. There are eight one-eighth inches per inch.


5. The tiny, densely-packed marks are for sixteenths of an inch. These are the shortest lines of all on most measuring tapes are the sixteenth-inch marks.

Catch the hooked end on one side of the object you're measuring.

Stretch the tape across your object. You can use one hand (or a friend) to hold the end of the tape in place as you pull it back. Let tape out until it stretches all the way across the distance you're measuring.

Read directly from the tape by looking at the point where the tape meets the end of the thing you're measuring or the desired measurement on the tape measure.

measurement A = 5 and 7/8 inches

measurement B = 6 inches

measurement C = 6 and 15/16 inches

The nearest number below the

end of the tape is your number of units you're measuring and the markings between this number and the one above it correspond to fractions of the unit.

6. Add the inch segments to determine total length. When you are measuring a length, getting an accurate value just means seeing where the tape lines up. Find the nearest inch before this point. Then, find the nearest half-inch before this point. Then, the nearest quarter-inch, and so on. Add up your inches and fractions of inches until you have an accurate measurement. This is a lot easier than it sounds — see below for an example.

Let's say that we've measured past the one-inch mark, past one quarter-inch mark, and past one eighth-inch mark. To find our measurement, we need to add:

1 (our inches) + 1/4 (our quarter-inches) + 1/8 (our eighth-inches).

Since there are two eighth-inches in a quarter-inch, we can rewrite this as:

1 + 2/8 + 1/8 = 1 3/8 inches.

Students may need assistance with adding fractions like 1/2, 1/4, 1/8, as they can be tricky for some students.


On most metric measuring tapes, centimeters are the most prominent markings. Centimeters are usually labeled with large lines and, next to each line, a number. As with inches, the line marks each centimeter, not the number itself.

Use the smaller markings between centimeters for 0.5 centimeters. Some (but not all) metric measuring tapes will have medium-sized marks evenly spaced between each centimeter mark. These marks are usually not labelled with a number.

The metric system is in base ten, which makes it much easier to work with decimals compared to standard measurements. For this reason, it's usually fine to refer to half-centimeter markings in decimal terms (i.e., 1 1/2 centimeters becomes 1.5 centimeters.)

Use the small, densely-packed markings for millimeters. There are ten millimeters in a centimeter (and, thus, one thousand in a meter.)

If your measuring tape doesn't have 0.5 centimeter markings, the fifth millimeter after each centimeter marks the 0.5 centimeter.

Add the centimeter segments to determine the total length. To measure with a metric measuring tape, first find the nearest centimeter before the distance you're measuring, then the nearest millimeter. You can use a 0.5 millimeter mark to help guide you if your measuring tape has them. Your measurement (in centimeters) will be a decimal where the tenths place is indicated by the millimeter marking. For example, see below:

Let's say that we measure past the 33 centimeter mark to the sixth millimeter marking. In this case, we can find our distance in centimeters like this:

33 + 0.6 = 33.6 centimeters

Some tape measures will have both standard units (feet and inches) and metric units.

Exploration: Pulleys and Conservation of WorkStudents will use hand tools to create an apparatus for investigating pulleys and conservation of work. They will use the mass added to a cup to determine the weight needed to lift a second mass. They will determine the work input/output ratio, examine the effects of a resistance force, and define


conservation of work. Once students have constructed their testing apparatus and completed the initial experiment, it is expected that they will complete the Explore section and then be given additional time to go beyond the written material and test their own ideas.

Students will need assistance in analyzing data, making calculations, understanding their results and communicating their findings clearly and concisely. It is imagined that here is where your expertise will be most valuably used. By focusing on safety and encouraging the exploration process students should be able to engage with the material on a deeper level. With that in mind here are some things to consider:

1. Help students understand that the more effort they put into building their testing apparatus, the more accurate their data will be.

2. Help students only as required. The more they are able to do on their own, with little input from you, the more ownership they will put into their experiment and their learning

3. Cutting small pieces from larger stock is easier than cutting from small stock. Help students plan out the steps they will take to build their testing apparatus prior to the actual build.

4. Encourage students to create a diagram of their testing apparatus, including the forces acting at all points of the apparatus. This will assist students in understanding their data and making connections with the content.

5. Though there are numerous ways to build their testing apparatus, assist students in making one that is similar to the sample apparatus pictured in the experiment. This will not only allow them to learn skills that will be used in future experiments but will also assist you in working with multiple groups.

6. A Standard weight set is specified as an item used for weight due to the fact that most science classrooms have them, and they are readily available. However, any machine nut would work just as well, with the added bonus of not being round and viewed as a toy to be played with rather than part of the experimental process.

7. It is not expected that students complete the Explore section sequentially, rather the questions there are intended as starting points for sparking inquiry. Assist students by asking “What if” and “Have you thought about” questions to give them direction and starting points.

It is assumed that students are familiar with some sort of reporting style and format, based on your own classroom expectations. This experiment can easily be turned into a formal Lab Report, mini Science Fair, Classroom Presentation, or even Journaling. It is encouraged however to use a rubric similar to the one below as a means of assessing student learning and skill progress.

General Scoring Rubric: ExperimentsAssigning grades on a percentage scale may not work with all experiments. The following rubric describes six levels of student performance associated with all experiments students conduct. To use this 4-point scale, read the description of each level and decide which description most accurately reflects each experiment you grade.

A helpful strategy may be to create a file of past papers that you feel exemplifies each level of the rubric. These could be scanned and kept as a digital file or hard copy, whichever works best for you. You would then be able to make this file available to students as a guideline.

Online Resources

https://www.physicsclassroom.com/class/vectors


https://www.explainthatstuff.com/pulleys.html

https://www.physicsclassroom.com/class/energy/Lesson-1/Definition-and-Mathematics-of-Work

http://cmse.tamu.edu/documents/LittlegreenBookletv3.pdf


http://cmse.tamu.edu/documents/LittlegreenBookletv3.pdf

€¦ · web viewin a previous lesson we utilized newton's first law of motion to predict...

Documents