Purpose:-To understand the definition of a simple machine -To understand how simple machines make work easier-To identify simple machines that we use in our day to day lives-To apply these concepts while designing and building a mousetrap car

Day 1:1. Introduction: Watch this 6 minute video on simple machines:https://www.youtube.com/watch?v=fvOmaf2GfCY

2. Activities:

Adopted from here.http://www.brighthubeducation.com/lesson-plans-grades-3-5/40964-simple-machines-lesson-with-examples-4th-grade-lesson/

Identifying simple machines (10-15 minutes)

Have students work with neighbors to make a list of examples of simple machines around them. Each of the machines should include the following description:

1. Name of the device2. The job that is made simpler3. The simple machine(s) used, as understood by the students.4. Any suggestions for changes that might make the machine better.

Have each explain two of their examples to the class. If they run out of examples, here are some extra ones:

Window blinds (if the classroom has these)- PulleyScissors: Wedge and leverJar with lid: screw Can opener: Wedge and wheelTape Dispenser: Wheel (technically there is also a wedge - teeth on the tape dispenser)

Slide: inclined planeBicycle: Wheel, pulley (chain), lever (pedals)Fan: screw (acts upon air to move it around)Mousetrap car demo (10-15 minutes):

Demonstrate how to use a mousetrap car (possibly in the hallway)

Explain the basics of how a mousetrap car works:-Mousetrap spring pulls on the lever arm which in turn pulls on the drive axle and causes it to spin.

After demonstration, ask the students to identify the simple machines on the mousetrap cars. -Pulley (the string moving the wheel)-Lever (the lever arm/snapper arm)-Wheel and axle-Screw (holds the pieces together)

Explain the options for building their car. Pass example pieces around so that the students can see what the options look like.

-big wheels vs. small wheels-short vs. long lever arm. -short vs. long body.

Explain the two competitions:-Build a car for speed (race to a finish line)-Build a car for distance (greatest total distance)

Have students choose partners and fill out the worksheet:-Pick a goal (speed or distance)-Discuss which car options they want(mentors should ask questions to get the students to think about how the options would affect car performance, but not give students the correct answers)-If there is time: Draw out the design for your car.

Have students hold on to their worksheets until next week.

Day 2:

Materials for 1 power/speed mousetrap car:● 1 victor mousetrap. ● 2 balsa wood sticks ~¼’’ x ¼’’ x 6’’ for short body.● 1 dowel rods ¼” x ~ 3” for lever arm.● 2 dowel rods ¼ “ x 3.5” for axles● 4 screw eyes. 0.079” wire diameter, ⅞” overall length, ¼“ eye opening● 4 rubber washers, ¼” ID and 1 ¼” OD. To be used as wheels.● Thin tape (~⅛”) to keep axle from sliding around in the screw eyes. May need to cut

tape.● 3 zip ties. One to act as hook, and 2 to tie the lever arm to the mouse trap.● Curling ribbon to wind the axle.● Glue gun.● Scissors● 12 mm x 5 mm screw eye for attaching ribbon to lever arm.● Straight-edge ruler.

Materials for 1 distance mousetrap car:● 1 victor mousetrap. ● 2 balsa wood sticks ~¼’’ x ¼’’ x 1’ (or longer)● 1 dowel rods ¼” x ~ 12” for lever arm● 2 dowel rods ¼ “ x 3.5” for axles● 4 screw eyes. 0.079” wire diameter, ⅞” overall length, ¼“ eye opening● 4 CDs to be used as wheels.● 4 rubber washers, ¼” ID and 1 ¼” OD. To attach axles to wheels● Thin tape (~⅛”) to keep axle from sliding around in the screw eyes. May need to cut

tape.● 3 zip ties. One to act as hook, and 2 to tie the lever arm to the mouse trap.● Curling ribbon to wind the axle.● Glue gun.● Scissors● 12 mm x 5 mm screw eye for attaching ribbon to lever arm.

● Dishwashing soap to reduce friction between axle and screw eye.● Straight-edge ruler.

Instructions for how to build a car:

1. Build the body of the mousetrap car. Glue the mouse trap to balsa wood sticks. Each side of the balsa wood stick should line up with the side of the mousetrap. The front of the mousetrap platform should be pushed against one end of the balsa wood. Make sure that the hammer of mousetrap is pointing towards the closer edge of the balsa wood sticks. See figure above.

2. Mark where you want to attach the screw eyes to the balsa wood. Be extra careful in this step. Make sure that the screw eyes will align. The more careful you are, the less your car will veer to one side and the less friction there will be between the axle and screw eyes. Do this for both the front and back of the body.

3. Attach screw eyes.

4. On the axles, mark where you want to place your wheels (~¼” from the ends of the dowel rods).

5. Insert axles into screw eyes.

6. Attach wheels. Glue wheels onto axle. If you want big wheels, then you must first glue the rubber washer to the CDs, taking extra care to make sure everything the holes are aligned. Then cover the wheels with rubber balloons to ensure adequate traction.

7. Place tape on axle to prevent axle from sliding around.

8. Attach zip tie to the hind axle. This will serve as a hook to wind your mousetrap car. Cut off the excess of the zip tie, but a little excess to make a good hook. It’s preferrable to have the hook near the same side as the lever arm.

9. Attach lever arm to mouse trap metal. Use 2 zip ties, and then hot glue those zip ties in place.

10. Attach string to lever arm. Tie a slip knot at the end that will attach to the axle.

11. Apply dishwashing soap to the screw eyes that are attached to the bottom of the car body. This will provide lubrication so that the axle can rotate with less friction.

12. Wind the string around the axle. 13. Place mousetrap on floor. 14. Let go. With some luck, your car will actually travel some distance.

Talk about safety considerations:Mentors must attach the snapper arm to the mousetrap. Mentors must use the hot glue gun.

By the end of Day 2 they should have a completed car

Finishing touches (15 minutes):

Test the cars and make sure they are working.Fix anything that breaks or gets tangled. Align wheels and make other tweaks as needed. Once students are satisfied with their cars, they can decorate them with stickers.

Day 3:

All cars will compete in both competitions.

Distance competition:Establish a starting line using masking tape on the floor.Place cars behind the starting line one by one.(Mentors should release the mousetrap?)After the car comes to a stop, measure the distance traveled with a tape measure. Have one of the mentors record the results in Excel. Note the attributes (big/small wheel, long

Speed competition: Mousetrap MotocrossStudents will have their cars jump off the edge of the table and measure how far they go. The farther they flew, the more velocity they had at the beginning.

Mousetrap cars will start ~1 ft from the edge of a table. Alternatively, students can decide where to release mousetrap car. Mousetrap should fly from the edge of the table. Measure the distance from where they mousetrap car landed to the edge of the table.Have one of the mentors record the results in the Excel spreadsheet.

Wrap up:Put the results spreadsheet up on the projector Sort the spreadsheet by longest distance. Look at the attributes of the cars that went the longest distance.

What do they have in common? Why do you think this is?

Attributes that should lead to a longer distance are:Large wheels, a long lever arm, a matched body

Ask/explain why these attributes lead to a longer distance traveled.

Sort the spreadsheet by the cars that went fastest:What do they have in common? Why do you think this is?

Attributes that should lead to a longer distance are:Small wheels, a short lever arm, a matched body

Ask/explain why these attributes lead to a greater speed.