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Sunday, February 26, 2012

Honoring Engineers during Engineers Week

We are taking a break from our Simple Machines unit in honor of Engineers this week to learn more about what they do in celebration of National Engineers Week, Feb. 19th - 25th. As part of our celebration and exploration, we've watched a video entitled "The Sum of All Thrills" found on Discover Engineering's website about a group of three teenagers that visit the Innovations area in the Epcot Center at Walt Disney World. These teenagers work with a pair of civil engineers to learn more about the physics and science that goes into designing theme park roller coasters. The teens are introduced to kinetic and potential energy, and then given the challenge of designing a couple of roller coasters, one on a marble track, the other on Epcot's "Sum of All Thrills" computer generated ride.

After seeing a bit of what civil engineers do (or at least those that design roller coasters), the younger students are given a lesson in aerodynamics as they learn a some of what aeronautic engineers do as they explore how balloons react to the air around them. This has lead to quite a few discussions about airplane and fighter jet designs, and streamlining the cone to allow it to effortlessly slice through the air like a wedge. (Some of the simple machines unit coming in.)

Meanwhile, the fourth and fifth graders have been challenged to design the tallest freestanding structure possible in a given time limit using only the supplies they are given in a zip lock baggie (10 index cards, 6 paper clips, 4 small drinking straws) and a foot of masking tape. They were allowed to use scissors to cut the cards as needed (making notches to interlock with each other), but were not allowed to use the scissors to add to their structure (as part of their structure). They could not have the structure taped to the table (thus, freestanding) and were not allowed to get more tape. A few taller structures came down with the wind as the buzzer went off on the timer, to the disappointment of the teams building them. The tallest structure for the week measured 68cm, but included a 30cm antenna made from the drinking straws.

Celebrating National Engineers Week with the students was a great way for them to learn a little more about what engineers do, and the impact engineers have on our everyday lives. Many of the students in our school have close ties to engineers through their parents. To all the engineering parents (relatives and friends, as well), this post is for you. Thank you for all you do to make our world a better place to live in.

The following video was put together with clips from our week and images that celebrate some of the different engineering fields.

Wednesday, February 15, 2012

Wedges help use separate materials

This week we have been taking a closer look at the wedge. Wedges help us by separating materials, lifting items, or holding things in place. They are made of two inclined planes put together, and are portable inclined planes, whereas inclined planes are stationary. Good examples of wedges are items made of metal that have a blade (like knives, scissors, and an axe) or a point (like a pin or staples). Keys could also be considered as a wedge because the teeth wedge their way into the tumblers inside a lock.

Primary students have been creating paper wedges in class, then separating the two inclined planes on them and driving toy Matchbox cars down the slopes. (Some have enjoyed jumping the cars on the ramps. :) Its been quite a trick working with the students helping them folds and tape all of the tabs on their paper wedges into place. (We've also discovered the metal teeth on the tape dispenser are a good example of a wedge.)

Intermediate students have enjoyed using the K'Nex sets to build a model of a wedge splitting a piece of wood. These models have been helping them understand how the wedge is used to separate the materials in the wood to split it.

Next week, we will be taking a look at inclined planes.

For more information about wedges, visit these sites:

Wednesday, February 8, 2012

Screws versus Bolts

This week we are taking a closer look at one of the six simple machines - the screw. Screws are useful simple machines in that they help us hold things together by applying force through the item or items. They can also take a force that goes around and make it go up and down instead. One of the earliest versions of a screw was invented by Archimedes and used to move water to higher levels in ancient times. Other examples of a screw beyond the kind used to hold materials together are springs, cork screws, and slinkies because they have a spiraling inclined plane wrapped around a central (or imaginary) core. Screws can also be found in nature, especially in shells and shelled animals.

Primary students are comparing screws to bolts using large screws and bolts I found (purchased) at Lowe's, and creating Venn diagrams to help them compare and contrast the two "screws". We have been talking about the ease of installing a screw into a wall because of the wedge on the end whereas a bolt would need to have a hole drilled first. Screws also have their threads (inclined plane) spread wider apart that helps to cut threads into the inside of the hole it is being screwed into; while the threads on a bolt are more standard (to fit nuts on them) and are closer together than on a screw.

The students are able to see how the threads are really one long inclined plane wrapped around and around by taking a paper cut into a right triangle, coloring the angled edge, and then winding it back around itself to make a paper screw.

Fourth and fifth grade students are exploring screws using K'Nex as they construct a hand drill and comparing a drill bit to a screw. They are also learning the mechanical advantages of a screw and how they can calculate the mechanical advantage (MA) by taking length of the spiral and dividing it by the length of the body of the screw (or drill bit, in this case).

For more information on screws as a simple machine, check out these sites: