Structures and Mechanics with fischertechnik Machines and Gears – Level 1
What You’ll Learn… • Principles of simple and compound machines • Principles of dynamics including force and mechanical advantage • What mechanical work is and how it is calculated • About different types of gears and how they work • How worm gears and toothed gears work • How to use the fischertechnik construction system Stuff You’ll Need… • Fischertechnik Profi Mechanic + Static Set • Mechanic + Static Activity Booklet • Mechanic + Static Assembly Instruction • Digital camera
ePortfolio Suggestions… • Before you begin the activities in this Learning Launcher, write down anything you already know about mechanics and gears. • List three interesting things you learned from the What You Should Know… section. • Keep a glossary of new words you learn. Pay particular attention to the bold, italicized words you find. • Take pictures of your fischertechnik models and label each of the parts. • Give examples of real machines that use similar gears. • Answer each of the questions in the Activity Booklet. Record your observations in your Project Planner. • Create a narrated video demonstrating how your geared machines work. • Find or take pictures of real machines that use similar gears.
What You Should Know… Getting to know fischertechnik… fischertechnik is a precision modeling system designed and produced in Germany. Like many modeling systems, fischertechnik is a great way to model structures and machines on a small scale. Unlike many modeling systems, fischertechnik is the choice of scientists and engineers for sophisticated modeling simulations and experiments. fischertechnik can be used to model large structures and simulate complex machines. With its sensors and computer programming capabilities, fischertechnik is even a sophisticated robotics system. Take the next 15 minutes and explore your fischertechnik Mechanic + Static collection. See if you can figure out the functions of the various parts and how they fit together.
What You Should Know… Mechanics… Mechanics is the area of physics concerned with the effect of forces on physical bodies. Mechanics is divided into numerous areas including statics, which is the study of structural systems that do not move, and dynamics, which is the study of bodies in motion. You can explore both statics and dynamics with your fischertechnik Mechanic + Static kit. In this Learning Launcher, we will focus on dynamics and machines. Check out the Level 1 - World of Statics Learning Launcher if you’re more interested in stationary objects like towers and bridges.
What You Should Know… A World of Machines… Can you imagine a world without machines? Every day, from the moment you wake up to the time you go to bed, you interact with machines. Machines are such a common part of our everyday lives, we don’t even think about them! But you couldn’t zip up your pants without a machine (yes, a zipper is a machine). You couldn’t wash your face without a machine (the faucet is a machine). You couldn’t leave the house without a machine (the doorknob is a machine). You couldn’t play hockey or baseball without machines (both hockey sticks and baseball bats are machines). And, of course, the very complex machines you normally think about, like cars, bicycles, play critical roles in our everyday lives.
What You Should Know… We design machines to help make work easier to perform. There are six types of simple machines. They are: 1) lever; 2) wheel and axle; 3) pulley; 4) inclined plane; 5) wedge, and 6) screw. When one or more simple machines are combined to help perform a task, it’s called a compound machine. Inclined Plane Wedge Screw Pulley Wheel & Axle Lever & Fulcrum
What You Should Know… How well do you think you are at identifying the six simple machines when they are hidden in your own home, garage, or tool shed? Take the EdHeads simple machines challenge and find out. Go online and test yourself to see how well you can do. If you get 100% correct on the simple machines, try the tool shed where the more challenging compound machines are hidden. Just click on “The House” to jump online to get started.
What You Should Know… Force and Work Given how important machines are in our everyday lives, let’s take a closer look at how they work – the study of dynamics. Since dynamics concerns the effect of force on moving objects, let’s first explore the concepts of force and work. Simply, force is a push or pull. Anything that causes a mass to accelerate (move faster or slower) is exerting force. Examples are gravitational force, magnetic force, or mechanical force like the motor in your fischertechnik kit! Mechanical force is commonly measured in newtons (named after Sir Isaac Newton who defined many of the Laws of Motion). One newton is the amount of force required to accelerate 1 kilogram (about 2.2 pounds) one meter per second squared. Is that a lot of force? Here’s another way to think about it - the force of gravityon a 1kg mass is about 10 newtons. So you are exertinga force of about 10 newtons when you are holding a 2.2 lb weight in the air!
What You Should Know… Work and Energy When force is applied over a distance we call it work. force x distance = work Work is a form of energy and is commonly measured in joules (after a physicist named James Prescott Joule). One joule is the amount of work when a force of 1 newton is applied over a distance of one meter. We can express it with the following formula: 1N x 1m = 1J
What You Should Know… Work and Energy The motor in your fischertechnik kit converts electrical energy into motion energy called work (and some heat energy too). Other parts in your machine transform this energy to apply a force (like the wheels turning on a car), and when this force is applied over a distance, your machine is performing work. Got it? Okay here’s a test… Your friend challenges you to a contest to see who can do more work. Since he’s one of the strongest kids in school, he finds the Facilitator’s car in the parking lot and pushes it with all his might. As hard as he pushes, he can’t make it budge. He strains and strains for almost 30 minutes, finally he collapses in a heap, totally exhausted. You watch him through the window somewhat amused. When he returns, he finds you sitting in the SmartLab with a pencil in front of you. With a casual flick of your finger, you make it roll across the desk and onto the floor. Who won the contest?
What You Should Know… Work and Energy You did of course! Remember: force x distance = work If distance is zero, no matter how much effort or force your friend applied to the boulder, if it didn’t move, work = 0. You might not have needed much force to move the pencil, and it might not have gone very far*, but you still had both force and distance so: work > 0 “I win”, you tell him. “Next time try releasing the parking brake”. Brains beats brawn every time!!! *By the way, even though the pencil went all the way across the desk and onto the floor, the only work was for the short distance your finger was actually pushing the pencil. The rest of the time, it was using other principles of physics to move - momentum and stored kinetic energy! Go online to learn more!
What You Should Know… Leverage and Mechanical Advantage In this Learning Launcher, we’ll be exploring the concepts of leverage and mechanical advantage. You already know that work is a product of force applied over a distance. It’s expressed by the following formula: If we want to perform more work, we can increase the force, increase the distance, or increase both. If we want to perform a fixed amount of work – like lift a 100 pound weight 1 foot, we can increase the distance over which work is performed, and use less force to accomplish the task. This is called leverage. force x distance = work
What You Should Know… Leverage and Mechanical Advantage Let’s look at how leverage works. If we wanted to lift a 100 pound weight one foot, it would require 100 foot-pounds of work. 100 pounds x 1 foot = 100 foot-pounds We could simply pull it straight up if we were strong enough. If we wanted to use less force, we could use the simple machine below, which is called a class 1 lever. Applied Force of 20 lbs. A lever is a simple machine to help us trade distance for force. Here we applied a force of 20 pounds over 5 feet to do the same amount of work. 20 lbs x 5 ft = 100 foot-pounds Distance 1 ft. Distance 5 ft. 100 lbs.
What You Should Know… Leverage and Mechanical Advantage When machines help make work easier by trading distance for force, it’s called mechanical advantage. The class 1 lever on the previous slide had a mechanical advantage of 5:1 (since we used 1/5th as much force to accomplish the same amount of work). Many machines are designed for this purpose. Gears, levers, pulleys and screws are just some of the devices we use to gain mechanical advantage. Do you think you’re strong enough to lift a car? Of course you are! There’s a machine in the trunk of your car called a jack to help you whenever you get a flat tire!
What You Should Know… We can also use gears to provide mechanical advantage. The motor in your fischertechnik kit isn’t very powerful. So, just like the lever in the previous slides, gears allow us to increase distance so we can perform work with less force. Let’s take a closer look at how gears can help machines like you will build with your fischertechnik kit gain mechanical advantage. Gears are variations of the wheel and axle type of simple machine. The teeth on gears transfer work from one gear to another. Remember how we use a lever with one side longer than the other to trade distance for force and gain mechanical advantage? Gears can create mechanical advantage in a similar way by using different size gears with different numbers of teeth. Instead of changing the linear distance we apply force (like we did by pushing down on the lever), we increase or decrease the rotational speed from one gear to another – one gear travels farther in a circle than the other. You will be using gears in many of your SmartLab projects, so it is helpful to learn more about them. You can watch this video if you need to learn more about gears.
Do It! Now try building a few simple machines to learn more about machines and gears! Start by building a simple worm gear pair. Find the Activity Booklet in your Mechanic + Static kit. Turn to page 23 and build the Worm Gear Pair as shown. You can find assembly instructions on page 5 of the Assembly Instruction book. Be sure to answer the questions in the Activity Guide and record your answers in your Project Planner! Assembly Instruction Activity Booklet
Do It! Machines and Gears… What did you learn about the uses of worm gears? Build the Turntable on page 23 of the Activity Booklet in your Mechanic + Static kit to explore a worm gear in action. You can find assembly instructions on page 8 of the Assembly Instruction book. Answer the questions in the “Your Task” section of the Activity Booklet. NOTE: Rather than using a cooking pot (kettle or pan) to test your turntable, we recommend using a stack of books. Be sure to record your observations in your Project Planner. Activity Booklet
Do It! Machines and Gears… Now let’s explore a different type of gear system – and one of the most common: Toothed Gears Build the Toothed Gearing system on page 24 of the Activity Booklet in your Mechanic + Static kit. You can find assembly instructions on page 11 of the Assembly Instruction book. Answer the questions in the “Your Task” section of the Activity Booklet.
Do It! Machines and Gears… Now that you know about toothed gears, you can use them to build a drive train like one used in many vehicles. You can design one of your own or build the Vehicle 1 or Vehicle 2 on page 25 of your Activity Booklet. Assembly instructions for Vehicle 1 can be found on page 13 of the Assembly Instruction book. Instructions for Vehicle 2 begin on page 18. Take pictures of your vehicle and explain how it works. Vehicle 1 Vehicle 2 If you have time, you can try building both vehicles!
Try building the Vehicle with Steering on page 26 of your Activity Booklet. Try building some of the other structures in the Mechanic + Static Assembly Instruction book. Or design one of your own. Try building one of the structural devices in the Mechanic + Static Assembly Instruction book. Take a photograph of a machine or find one on the internet. Can you find gearing systems similar to the models you just built? Go online and search for “fischertechnik projects”. Check out some of the amazing things people have built using this sophisticated modeling system. Extend Yourself…