Levers

Wheels and Axles

Gears

Pulleys

Grade Level Range
Introduction    Grades 2-4
Reinforcement    Grades 5-8

Brief Description of Lessons and Activities
The following lessons were developed to follow Watervilleís 3rd grade science curriculum for simple machines (inclined plane, lever, gears, pulley, and wheel and axle).  The lessons will allow students to make observations, do experiments, and use results in a purposeful way.  Students will create functioning models that demonstrate ways in which simple machines make work easier
    One of the ways students will create models is using the Lego Dacta Technic kits.  They will not only use the accompanying task cards, but will also create original projects.  Students who learn tactilely are especially successful at this type of learning experience.

Management
The Dacta kits can be used as a great resource for teaching simple machines.  The kits are numbered.  Students should be paired and assigned a kit to be used for the duration of the entire unit.  The students assigned each kit are responsible for ensuring that all pieces are kept intact in the kit.  Each kit contains task card #1, which is a visual model of the complete list and placement of parts.  Students should refer to this card when they first receive the kit to account for any missing pieces.  They should also use this as a guide when returning the parts after an activity.  Refer to the back of card #1 to view how to insert the plastic cover as a stand for the task cards.

Additional Resources
The following internet link will take you to a site that has links for 9 student sites as well as 4 sites for teacher resources.  There is an abundant amount of information on these sites.
http://seamonkey.ed.asu.edu/%7Ehixson/index/machines.html
Childcraft Volume 12 How Things Work  p.57-97 (Beginning elementary explanations of the different simple machines)
Simple Machines by Deborah Hodge (Projects demonstrating simple machines)
Just a Little Bit by Ann Thompert (Literature using seesaw as a lever)
Dr. Desoto by William Steig (Literature containing many illustrations of simple and complex machines as part of the story)
Mike Mulligan and His Steam Shovel by Virginia Lee Burton  (Used  as a writing prompt to assess knowledge of simple machines.  The story is read to the part where Mike is stuck in the hole.  Students complete the ending by solving a way for Mike and Mary Anne to get out of the hole using simple machines.)

Levers Lesson #1     "Lift the Teacher"

Suggested Groupings
Whole class discussion and demonstration

Maine Learning Results Performance Indicators
Science and Technology  J2, J3

Materials
Rigid board about 6 feet in length
Block or brick for fulcrum
Teacher and students

Lesson Activities
Key Questions:
How can the teacher (or another student) be lifted using a board and block?
Where should the fulcrum be placed to lift the teacher with the least amount of effort?

Brainstorm with students ways to lift the teacher.  (Or ways the teacher might lift a student with just one hand!)  Try some of these if feasible.  Bring out the lever (board and block).  See if a student can "lift" the teacher.  Experiment with moving the fulcrum to change the amount of effort needed.

Lesson#2    " Lever Experiment"

Suggested Groupings
Whole class introduction and then students working in pairs.

Maine Learning Results Performance Indicators
Science and Technology   J2, J3, L4

Materials
For every 2 students:
A ruler with a small paper cup taped to each end
A piece of clay for a fulcrum
1 rock
Counting bears or something used as weights
Activity sheet to complete

Lesson Activities
Key Question:
How does the position of the fulcrum affect the amount of effort needed to lift the load?
Procedure:
   1: Assign students to work in pairs.
   2. Discuss the key question.
   3. Discuss the experiment and activity sheet to complete.
   4. Distribute materials.
   5. Have students follow directions to complete experiment and activity sheet.
   6. Discuss conclusions and encourage students to see the patterns between the placement of the fulcrum to the load as        compared to the amount of effort needed.

Lesson#3     "Lego Dacto Lever"

Suggested Groupings
Whole class modeling of how to use the kits and then assign students in pairs to use Dacto kits.

Maine Learning Results Performance Indicators
Science and Technology  L4

Materials
Lego Dacta Kit for each pair of students

Lesson Activities
Key Question:
Demonstrate your knowledge of how levers work using the Dacta kit and task card #4.
Procedure:
1. Instruct students to use task card #4 to create a lever to lift a lego "brick".
2. Students should experiment with moving the fulcrum and comparing the amount of effort needed to lift the brick.
3. Students should explain the concept of lever and placement of fulcrum.

Extensions:  Students that have been successful in using the Lego Dacta kit to make the lever may wish to make the other examples of levers on task card #4 as well as use other appropriate task cards.

Lever Experiment        Name

Materials:
1 clay ball to be used as a fulcrum
1 ruler with a small paper cup taped to each end
1 rock
 counting bears

Hypothesis: Which one do you feel will balance with the least amount of effort?
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________

Procedure:
Put the rock in one cup at the end of the ruler.
Place the ruler on the clay fulcrum at the 6 inch mark.  Put bears     into the cup until the ruler balances. Count how many bears it     took to balance the ruler.
Place the ruler on the clay fulcrum at the 8 inch mark.  Put bears  into the cup counting how many it takes to balance the ruler.
Place the ruler at the 4 inch mark.  Again put bears into the cup     counting how many it takes to balance the ruler.
Record your observations.  Label the fulcrum, load, and effort:

Observations:
How many bears did it take to make the ruler balance?
Labels:  F=fulcrum   L=load    E=effort

__________       ___________   __________
 

6 inches=_____bears  8 inches=_____bears  4 inches=_____bears
 

Conclusions:  Which one took less bears (effort)? ________________________________________________________________________

Why?___________________________________________________________________

Which one took the most bears (effort)? ________________________________________________________________________

Why? ________________________________________________________________________
 
 

Description
In this investigation students will understand that a wheel and axle is a simple machine that helps us apply more force or lift a heavy load with less effort. A wheel and axle have a large wheel and a cylinder that are fastened together and turn together.  As the wheel and axle rotate, the wheel moves a greater distance than the axle, but it takes less effort to move it.  The axle turns a shorter distance, but it turns with greater force.
    Putting wheels and axles on something makes it easier to move.  Without wheels, something such as a wagon would drag on the ground.  The scraping or friction of the wagon on the ground would make it hard to pull the wagon.  Wheels and axles allow you to move big loads with very little friction.

Lesson #1   "Wheel and Axles Using Skateboards or Scooters"

Suggested Groupings
Whole class for demonstration with toy car and then groups of 2 students for experiment with books/scooters and experiment with Dacta Kit.

Maine Learning Results
Science and Technology  J  2 & 3, L 4

Materials
1 plastic car or truck for the teacher to model concepts with.
3-4 heavy text books for each pair of students to use.
1 skateboard or scooter for each pair of students to use.  ( See the gym teacher to borrow.)
1 piece of string long enough to go around the books for each pair of students.

Lesson Activities
Key Questions:
If you have to move something that is heavy and impossible to carry, what simple machine would you use to help move the heavy object and make work easier?
Which do you think will be the easiest to pull across the floor- a stack of books pulled by a string across the floor or a stack of books placed on a skateboard and pulled across the floor?
Pull the stack of books across the floor.  Think about the effort it took.
Pull the stack of books across the floor while on top of the skateboard.  Think about the effort it took.

Which way took the least amount of effort to move the books?  Which way took the most amount of effort to move the books? ( Can also determine how much effort using a spring scale)
How do wheels and axles make work easier?

Procedure
1)  Show students a toy car without wheels or axles.  Ask one student to push the car on a table or desk. Ask the students:
" How well does this car move?"  " What is missing from the car?"  Make sure the students mention the missing axles as well missing wheels.  If they donít know what the rod connecting the wheels is called, provide the word axle.
2)  Tell students that in this case, a wheel and axle is a simple machine that helps us move the car with less force.
3) Explain the experiment that the pairs of students will be doing, using the step by step worksheet as a guide. The following is the worksheet:

Name ____________________________________ Date________________

A) Hypothesis:   Which do you think will be the easiest way to pull  books across the floor:  pulled by a string while resting on the floor or the same amount of  books stacked and pulled on a skateboard or scooter?
__________________________________________________________________________________________________________________________________________________________________________________________-------------------------------------______________________________
 

Step 1  Tie the string around the books.
Step 2  Pull the books across the floor.
 

B)  Think about the effort you used to pull the books across the floor.  Would you want to pull heavier objects such as a refrigerator this way- why or why not?
________________________________________________________________________________________________________________________________________________________________________________________________________________________
 

Step 3 Place the books on the scooter.
Step 4 Pull the books across the floor again while they are
          resting on top of the scooter.

C)  Think about the effort needed to pull the books on the scooter.  Was more or less effort needed to pull the books just on the floor compared to wheels?
________________________________________________________________________________________________________________________________________________________________________________________________________________________

D)  What simple machine made moving the books easier?
________________________________________________________________________

E)  How do wheels and axles make moving objects easier?
________________________________________________________________________________________________________________________________________________________________________________________________________________________

F)  Brainstorm some examples of wheels and axles that you use to make work easier.
________________________________________________________________________________________________________________________________________________

Lesson # 2      "Wheels and Axles Using the Dacta Kit"

Materials
1 Lego Dacta Kit for each pair of students
1 copy of task card #10 for each pair of students

Lesson Activities
Key Questions:
1)  Was there more effort needed to pull the Legos or the Legos on wheels?
2)  How do wheels and axles make work easier?

Procedure
1)  The students will work in pairs to create the wheel and axle model from Task Card #10.
2) The students will create the model as far as step 4 and then will try to pull or push it across the table.  They will make a  judgment on whether it took more or less effort to move the Legos.
3) The students will complete the building of their Legos (Steps 5& 6)

Extensions
A)  Complete the second half of Task Card #10
B)  Complete Dacta Task Card #11 creating a conveyor type belt made out of wheels and axles that helps to slide a Lego up and down a ramp.

Brief Description of Lessons and Activities
Gears are wheels with teeth.  The teeth make it possible for the wheels to mesh together and for one wheel to turn another.  As one gear turns, it transmits force to the next, which also turns.  Gears, like other simple machines, make work easier by: (1) changing the speed of motion, (2) changing the force of motion, or (3) altering the direction of the motion.
In all gear patterns, one gear will turn faster or slower than the other, or move in another direction.  A difference in the speed between the two gears will also produce a difference in the amount of force they transmit.  A slower moving gear will transmit much greater force.  Children with bikes that can shift gears will be able to test as they ride home from school.
 We use gears in mechanical watches, lawn mowers, cars, bicycles, salad spinners, dentistsí drills, egg beaters, a bit and brace (hand drill), and windmills.  The Lego Technic Cards # 6, 7 and 12 show excellent examples of modern gears at work.
    The Lego kits offer children the chance to work with two basic gear groups:
Spur Gears mesh in the same plane.  Children may think of this as gears that can line up in a row. They regulate the speed and force of motion and reverse its direction.  Activity Cars 6 and 12 use spur gears.
Bevel Gears mesh at an angle to change the direction of rotation from one plane to another.  Children could think of them as gears that turn a corner.  Bevel gears may also change the speed and force of motion.
Some gears are connected by belts or chains instead of intermeshing teeth.  Although they work in exactly the same way as the gears above, they donít change the direction of the motion.  The chains connecting the front and back sprockets on the childrenís bikes are belted gears.

Gears Lesson #1   "Student Gears"
(Adapted from Human Gears, the Boston Museum of Science teaching ideas)

Grade Level
Grades 2-3

Time Required
15-35 minutes, depending on how many variations are used

Suggested Grouping
This activity will involve the full class.
Use 10 children at a time for this activity.  Have children draw a gear number out of a jar.  You should have four slips labeled "4", three slips labeled "3", two slips labeled "2" and only one slip labeled "1".  (Note:  Gear #1 will spin the fastest and have the greatest needed for self-control.  You may want to assign this role, rather than leave it to chance.)

Maine Learning Results-Science and Technology
I-1  Show the effects of types of mechanical forces on motion
J-2  Conduct scientific investigations
J-3  Make observations based on observed patterns
K-3  Draw conclusions about observations

Materials
Open space
Cord lengths or large loops of 1" sewing elastic

Lesson Activities
How do gears mesh?  When you turn one gear in a pattern, how do the other gears react?  Can you predict the action of the next gear?  How does the speed of a gear change as the number of teeth changes?
Each of the ten participants will extend his or her arms to be the teeth of a gear.  The gears will combine to create a gear pattern.

Gear #1 is only one person.  S/he stands alone with arms stretching out straight from his or her body.
Gear #2  is two people standing back to back with shoulders touching.  To make four teeth, they hold their arms out straight, but at an angle of 90 degrees, as if they are holding a big, imaginary box.  A piece of cord or elastic around their waists will help them stay together.

Have the two "gears" stand so that a Gear #1 arm is in between the arms of a Gear #2 person.  Explain that you are the force of this machine and you are going to send this force along.  Start Gear #2 turning slowly, keeping their feet in place.  Have the children watch what happens to Gear #1.  Does it move faster or slower than Gear #2?  What direction does each Gear turn in?  Stop before the children get dizzy and lose their footing.

Create Gear #3 with three people, shoulders touching and arms out at about 60 degrees.  Tie their waists together as before.  Connect Gear #3 to your pattern by having the smaller gears move in to connect.  (It will always be easier to move the smaller groups.)
Start the gear pattern moving by gently helping Gear #3 to start spinning.  Have the children report again on which gear moved fastest?  Slowest?  In which direction did each gear move?

Create Gear #4 with four children, shoulders touching and arms out at about 45 degrees.  Tie their waists together.
Before adding them to the pattern, ask the children to predict:
Which gear will move most slowly?  Most quickly?  In which direction will each gear turn if the teacher starts Gear #4 going clockwise?
Have the smaller gears move in to connect which Gear #4 and start Gear #4 moving slowly clockwise.  Run the "machine" until the watchers have been able to check their predictions against the actual gear movements.
    Discuss the observations the children have made about gear movements and speed.
    Repeat the experiment using children who have been observers.  Setting up the gears will go much more quickly, since the children have clear expectations about the procedures and outcomes.  Run the experiment in the same way, letting the children predict the direction of every new gear as itís added.  Now before Gear #1 is a total dizzy wreck, reverse the action and let Gear#1 start turning so that his/her motion controls the turning of the other gears.

Extensions
Try mixing and matching gear sizes in a machine that uses everyone in your room.  How will the force be transferred?
Can you still predict which direction a gear will turn in?  Can you make predictions about the relative speeds of each gear?
If your group has managed this activity without mishap, consider combining with another class to make a "super machine".  Gear # 5 would have 10 teeth, Gear #6 would have 12 teeth, etc.
 

Gear Lesson # 2   "Gear Race"
Gear Race, a possible "quicky" follow-up to the previous activity (while the childrenís energy levels drop) or an alternate intro for groups for which a very physical activity is not appropriate.  This activity can be easily performed by a child seated in a wheelchair or limited by other mobility problems.

Grade Level
Grades 1-3

Time Required
5-10 minutes

Suggested Grouping
Two children will be involved in a race to create the most soap bubbles in a bowl of water.  Other children can be involved in the set-up of the materials.  This is a good time to reinforce the idea that in a scientific study, the conditions must be the same for each repetition of an experiment.  A child can be designated as the stop-watch or clock watcher.

Maine Learning Results-Science and Technology
I-1  Show the effects of types of mechanical forces on motion
J-2  Conduct scientific investigations
J-3  Make observations based on observed patterns
K-3  Draw conclusions about observations

Materials
Egg beater
Fork
Dish washing liquid
Two bowls of the same size
Water
Sponges/paper towels
Stop watch or classroom clock

Lesson Activities
How do the gears of an egg beater affect the speed of its rotating beaters?
Have a student carefully put equal amounts of water in each bowl.  Have another student measure and add equal amounts of dishwashing liquid to each bowl.
Give Volunteer #1 a fork and Volunteer #2 an egg-beater.  Give the children a chance to discuss the ways in which the two pieces of equipment are the same or different.
Tell the class that this is a race in which the Volunteers are to make the most bubbles as quickly as possible.  When you call GO!, both volunteers will start beating the soapy water as fast as they can.
Ask the class to predict which Volunteer will be more successful and why.
Run the test for one or two minutes and call STOP.  Have the class vote on which bowl contains more bubbles.
Discuss why the egg-beater was more successful at churning bubbles than the fork.
Have a student point out where the gears are located in the egg-beater.
How many times do the beaters rotate for each rotation of the handle?  Have the students watch carefully and count while you turn the handle.

Gears Lesson #3  "Use the Lego Dacta Materials to Explore Gears"

Grade Level
Grade 3-8

Suggested Grouping
Following the guidelines set out in the "Management" section, assign children to work areas with assigned kits.
Cards 6 and 12 explore spur gears.  Card 7 invites children to create a bevel gear.
As the children build the gear assemblies using the picture guides, they should be able to demonstrate an understanding of how gears mesh.  They should be able to predict the direction in which second and third gears will turn.  They should be able to show how the gears move the force through the machine.

Background Information:
A pulley is a type of lever that uses a wheel as a fulcrum and a rope or belt as the lever arms.  A pulley can change the direction of a force.  With a single pulley, a person can pull down on a rope and yet lift an object up.  Activity #1 demonstrates this principle.
    A system of several pulleys may not only change the direction of the force, but may also amplify the effort.  Of course, no new energy has been created.  The increase in energy was at the expense of distance: the amount of increase is equal to the number of lines of support within the pulley system.  This principle is demonstrated in Activity #2.

Pulleys Lesson #1
Adapted from teaching materials from the Boston Museum of Science.  This activity uses two fixed pulleys (they donít change position.)  Fixed pulleys can make work easier by changing the direction of the force, but they donít increase the force you can use.  This pulley set-up is very similar to the old-fashioned laundry line.

Time Required:
15-20 minutes?

Suggested Grouping:
Full class, with lots of open floor space.

Maine Learning Results-Science and Technology
I-1  Show the effects of types of mechanical forces on motion
J-2  Conduct scientific investigations
J-3  Make observations based on observed patterns
K-3  Draw conclusions about observations

Materials:
2 Pulleys (also available from ARC in the Pulleys Kit, or use ones from home)
Heavy cord
(Scissors to cut cord)
Paper clips
Paper and pencils for message writing

Procedure
Using short pieces of cord, anchor the two pulleys at least 10 feet apart in your classroom (tied to heavy chairs or desks.)  In a pinch, two very steady children can be the pulley holders.
Thread a long piece of the cord through one pulley, across the room and through the other pulley.  Tie the tow ends of the string together, taking almost all the slack out of the loop.
Have half the class gather at each end of the pulley.  Each child can pick a partner on the other side to write a message to.
Have a child clip a message to the lower part of the cord near one pulley.  To send the message, s/he then pulls the upper part of the cord towards him, hand over hand, until the message reaches the other pulley.
Reinforce the idea that the pulley allowed the students to pull the cord toward them, while sending the message away from them.
 

Pulleys Lesson #2   "Meet the Equalizer"
The following activity was adapted from the AIMS 1993 Machine Shop book and shows how multiple pulleys create a mechanical advantage.  It is a great way to make this point without having to find a way to attach fixed pulleys to some surface in your classroom.

Grade Level
Elementary classes

Time Required
15-20 minutes?

Suggested Grouping
Full class, with lots of open floor space.  Various volunteers will be needed.

Maine Learning Results-Science and Technology
I-1  Show the effects of types of mechanical forces on motion
J-2  Conduct scientific investigations
J-3  Make observations based on observed patterns
K-3  Draw conclusions about observations

Materials
50 feet of smooth-surfaced synthetic rope
2 broom handles or 2 36in. pieces of 1" dowel
(1 short dowel)
( gloves, if readily available, to prevent rope burns)

Lesson Activities
Youíll need three students to do the first demonstration. (It will be fun to use a small student for the role of student #3, "the puller".)
First have the first two students hold one end of the rope and the third student the other.  Ask the third student to pull the other two some small designated distance.
Ask the class to speculate on why this didnít work.  (Two people are generally stronger than one when pulling directly against one another.)
Give each of two students a pole/broomstick and ask them to stand a few feet apart facing each other, holding the broomsticks out in front of them.
Explain that although the third student cannot become instantly stronger, we can give her/him a mechanical advantage.
Tie the end of the rope to one of the broomsticks (nearer one end would be good) and loop it around both broomsticks several times (making a series of rope triangles) while the students continue to stand several feet apart..
Ask the third person to pull on the free end of the rope.  No matter how hard the pole holders resist, the third student should be able to pull them together.
    Repeat the activity using other class members.  Vary the number of students resisting "the puller."  Vary the number of times the rope is looped around the poles.  What patterns can the children see?  (The greater the number of loops used, the greater the force available to pull the resisting students together.)
    If you can move outside, tie one end of the rope to the flagpole.  The rope is then looped around both a broomstick and the flagpole several times.  The "free" end of the rope is then tied to a dowel.
Have one student pull on the dowel end, while a team of two or three people pull on the broomstick that is looped several times by the rope.  The individual should be able to win the tug-of-war because of the mechanical advantage of the pulley system.  Each line of support increases the advantage.

Pulleys Lesson #3  "Use the Lego Dacta Materials to Explore Pulleys"

Grade Level
Grade 3-8

Suggested Grouping
Following the guidelines set out in the "Management" section, assign children to work areas with assigned kits.

Procedure
Ask student groups to create the pulley system on Card #16.  Make sure they notice that this task in progressive and involves two steps.  By following the directions up to step six, they are creating the simplest kind of pulley system: one that merely changes the direction of the force.
When they next modify their project (see the last two pages), they will be using a multiple gear system, which allows them to use less force.  Most groups will do either one, but not both, of the secondary projects.  The page marked with number 1 highlighted in yellow is probably the easier of the two.
Ambitious students who work quickly may want to attempt the belt and pulley system in Card #5.