Authors: Maddie Van Beek and Dr. Erin Nyren

​Merry Christmas! This is the last of our holiday science. Use some of the sweets around your house to build gingerbread houses! You can either make your own gingerbread, or you can use graham crackers for your building. Before you start building, let’s learn a little bit about building structures.


What kinds of shapes do you usually see in houses? Think about the buildings you see every day. What shapes does your house have?


You probably can find circles, squares, and triangles in any building you look at. Walk around your neighborhood and record the kinds of shapes that you see!


What’s more sturdy, a square or a triangle? Test it out. Connect three marshmallows with toothpicks to create a triangle. Next, connect three marshmallows with toothpicks to create a square. Squeeze both shapes and try to move them around... which is more sturdy? You probably noticed that the triangle kept its shape better than the square. That should help you as you think about how to build your structure!


There are four things that every building needs to be stable and provide shelter:
1. Foundation: The base of the building.
2. Floor: The part of the building we walk on.
3. Walls: Defines the building, divides the building into rooms, holds up the roof.
4. Roof: The top of the building that provides shelter for the people inside.


Below is an example of a simple house structure. See if you can build one! Try out your own ideas with the shapes you’ve seen around your neighborhood. Be creative!

Now that you’ve practiced your building, let’s make gingerbread houses!


Here’s some examples of houses that we built with graham crackers last week!

YOU WILL NEED:
* Marshmallows
* Toothpicks
* Gingerbread or graham crackers
* Royal icing (recipe below)
* Plastic baggies
* Scissors
* Paper plate or pan
* Assorted candies (licorice, chocolate candies, gum drops, and anything colorful works great!)


To make royal icing:
Using an electric mixer, combine 2 pounds (1 kilogram) of powdered sugar with 4 large pasteurized egg whites. Blend until the mixture is smooth, with no lumps of sugar. It should be stiff and sticky!


Here’s what to do!
1. Draw your building plan on paper first. It always helps to have a plan!
2. Spoon frosting into a baggie and seal it. Cut off just the tip of one corner of the bag. This will be your icing tool.
3. Break up your gingerbread or graham crackers into the shapes you want to use for your house.
4. Use a pan or paper plate for your construction area. Build your structure using your shapes for your structure and frosting for glue! If your building collapses, don’t worry! You can always try again. Sometimes it takes a few tries to find the right building technique, and it does take a while for frosting to solidify.
5. Once you build your structure, use candies to decorate your house. Have fun, and Merry Christmas!


Image and video credits, in order of appearance: 
House diagram created by Dr. Erin Nyren
Photos taken by Maddie Van Beek

Author: Maddie Van Beek

​Thanksgiving is coming up! One of the most popular Thanksgiving staples are cranberries. Cranberries are small, red berries that grow on a shrub. They’re usually sweetened into a sauce or jam, often for Christmas or Thanksgiving.

At the holidays, you might see whole cranberries, jellied cranberries, or cranberry sauce. How can we use cranberries for science? Let’s find out!

Cranberry Reactions

Watch cranberry juice react with baking soda and lemon juice!

There are two reasons that cranberries are going to react in our experiment today. One, cranberries are acidic. As you might know, when acids and bases meet, a chemical reaction takes place. You’ve seen this happen when you mix baking soda (a base) and vinegar (an acid). What happens? Lots of fizzing and bubbles! Remember, those bubbles are releasing carbon dioxide gas as a product of the reaction. The second reason that you’ll see a special reaction from cranberries is because of their pigment, anthocyanin. Anthocyanin is what makes cranberries their deep red color. When the acidity changes in the juice, anthocyanin reacts by changing color! Today, you’re going to mix cranberry juice with baking soda and lemon juice to see how these ingredients react with each other.

YOU WILL NEED:
* Cranberry sauce, juice, or whole cranberries
* Baking soda
* Lemon juice
* Glass or container
* Measuring spoons


1. If you’re using cranberry sauce, make sure it’s thawed out and in liquid form. If you’re using whole cranberries, mash them up and add a little hot water to get a good amount of juice.
2. Pour the cranberry juice into a glass. You should have at least one cup of juice.
3. Predict what will happen when you add a spoonful of baking soda to the glass of cranberry juice.
4. Add the baking soda and observe what happens. Record your observations.
5. Predict what will happen when you add lemon juice to the cranberry juice.
6. Add two tablespoons of lemon juice and observe the reaction! What happened?
7. Record your findings.
8. Extension: Add different amounts of baking soda or lemon juice. Does that make a difference? Can you get the color to change even more? What happens if you add baking soda and lemon juice at the same time?


Cranberry Building

In this activity, you will use cranberries to build the tallest structure possible!


YOU WILL NEED:
* Fresh, whole cranberries
* Toothpicks


Here’s what to do!
1. Unwrap your cranberries.
2. Connect two cranberries with a toothpick.
3. Continue building and connecting cranberries to build whatever structure you want. See how tall you can make your building before it tips over!
4. Test out the strength of your structure by setting an object on top. See how much your structure will hold!
5. Challenge: Try rationing yourself to only 20 toothpicks. Using those 20 toothpicks, what shape will create the strongest structure? Try a few different structures and test which one is the strongest!


Cranberry Sauce Recipe

Here’s a great cranberry sauce recipe that you can use for the holidays! Impress your family by helping out with this traditional treat!


YOU WILL NEED:
* 12 ounce bag of cranberries
* Sugar
* Orange zest
* Pepper
* Water
* Salt
* Pan
* Stove

Here's what to do!
1. Empty your cranberries into a saucepan.
2. Transfer 1/2 cup of the cranberries into a small bowl. 
3. Add 1 cup sugar, 1 strip orange zest, and 2 tablespoons water to the saucepan. 
4. Stir over low heat until the cranberries soften and the sugar dissolves.
5. Increase to medium heat cook until cranberries burst. 
6. Reduce to low heat and add the 1/2 cup of reserved cranberries. 
7. Add sugar, salt, and pepper to taste. 
8. Let cool to room temperature before serving.  

Recipe from: 
http://www.foodnetwork.com/recipes/food-network-kitchens/perfect-cranberry-sauce-recipe.html

Image credits, in order of appearance:
Weller, K., 2005. Cranberry bog. Image uploaded from Wikimedia Commons on 11/13/2016. 
https://upload.wikimedia.org/wikipedia/commons/thumb/3/3a/Cranberry_bog.jpg/1024px-Cranberry_bog.jpg
File in the Public Domain. 

Cjboffoli, 2010. Cranberries20101210. Image uploaded from Wikimedia Commons on 11/13/2016. 
https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Cranberries20101210.jpg/1024px-Cranberries20101210.jpg ​File used in accordance with the Creative Commons Attribution-Share Alike 3.0 Unported license. No changes were made.

Veganbaking.net, 2008. Cranberry sauce. Image uploaded from Wikimedia Commons on 11/13/2016. 
https://upload.wikimedia.org/wikipedia/commons/thumb/0/07/Cranberry_Sauce_%283617909597%29.jpg/800px-Cranberry_Sauce_%283617909597%29.jpg 
File used in accordance with the Creative Commons Attribution 2.0 Generic license. No changes were made.

Author: Maddie Van Beek


At one point in your life, you have crossed a bridge. Think about the different bridges you have crossed. Were they arched? Flat? Did they have cables running through them? Were there pillars on both ends or beneath the bridge? While there are many visual and structural varieties, all bridges span a distance to get you from point a to point b. There are five main categories of bridges.


Today, you are going to be an architect! An architect is someone who designs buildings and structures so they are steadily built.  Before you start building, you need to know a little more about the different types of bridges. 

 

Bridge Types

1.  Beam: The beam bridge is the simplest type of bridge. This bridge is stiff, straight, and generally short with two piers or abutments on either end. The beam bridge spans, at most, 250 feet. 

2. Arch Bridge: Just as the name suggests, this bridge is arched. Similar to the beam bridge, this bridge has two piers or abutments. The curved design allows stress to be distributed along the arch to either end. This design can span up to about 800 feet. ​

4. Cable Stayed: This bridge, like the suspension bridge, is supported with steel cables. The cables run from the road to a tower, forming an A. The cables are taught and run parallel to one another. The cable stayed design is popular for mid-length bridges, not far over 3,000 feet. ​

Use the following bridge diagrams as a reference: 

YOU WILL NEED:

•   Paper/Pencil

•   42 Gum Drops

•   7 Red

•   10 Green

•   8 Yellow

•   9 Orange

•   6 Purple

•   2 White 

•   One bag of toothpicks 

 

Here's what to do!

1.  Partner up with one to three others. 

2.  Assign a runner to get supplies, a time-keeper, and a group leader. 

3.  Design your bridge. Before you start building, you need to plan. You should be able to answer these kinds of questions: 

            a.What kind of bridge will you design? 

            b. Will you rely on one type of bridge, or will you combine two types for a more elaborate design? 

            c. What criteria are you basing your decisions on? Attractiveness? Strength? 

            d. How far will your bridge span? How high do you want your bridge to be? 

4. Use your gumdrops and toothpicks to build a bridge based off of one of the five bridge types. Use your drawing to guide you. 

            a. Once you are finished building, you will be judged based on strength and appearance. 

6.  For the last ten minutes, try building your bridge in silence. All team members must continue to participate. 

7.  Stack pennies on your bridge to see how many it will hold! Have a contest to see who has the strongest bridge. 

 

Follow-up Questions:

• How well did you work together as a group?
  
• How much harder was it when you couldn’t talk?
  
• Do you feel like everyone was included in your group?

​
Image Credits:

​Image 1: Jones, D.W. (2006). Steam across Iowa river. Retrieved from https://upload.wikimedia.org/wikipedia/commons/thumb/1/10/SteamAcrossIowaRiver.JPG/240px-SteamAcrossIowaRiver.JPG

​Image 2: Bulwersator. (2004). Double arch stone bridge, Japan. Retrieved from https://en.wikipedia.org/wiki/Arch_bridge#/media/File:NagasakiMeganebashi.jpg

Image 3: Unknown photographer. (1890). Postcard of Benjamin Baker's human cantilever bridge model. Retrieved from https://en.wikipedia.org/wiki/Cantilever_bridge#/media/File:Cantilever_bridge_human_model.jpg

​Image 4: Bayakov. (2013). "Russian bridge" in Vladivostok. Retrieved from ​https://upload.wikimedia.org/wikipedia/commons/thumb/e/eb/%22Russian_bridge%22_in_Vladivostok.jpg/1280px-%22Russian_bridge%22_in_Vladivostok.jpg

Image 5: Underhill, I. (1909). Manhattan bridge construction 1909. Retrieved from https://upload.wikimedia.org/wikipedia/commons/thumb/1/1c/Manhattan_Bridge_Construction_1909.jpg/800px-Manhattan_Bridge_Construction_1909.jpg


References:

List of bridge types. (2016). Wikipedia. Retrieved from https://en.wikipedia.org/wiki/List_of_bridge_types

Author: Maddie Van Beek

It has been an incredibly windy day in Fargo! Wind may be annoying, but can also cause major issues! For example, wind can cause erosion of natural formations like mountains and hills as well as manmade structures such as buildings and walls. Erosion often occurs in flat areas where there are few natural wind blocks. Fargo is the perfect example of this type of landscape, as it has little trees and very few hills.


What exactly is erosion? Basically, erosion is a slow, steady destruction of something, often due to wind or water. Here’s a few examples:

http://examples.yourdictionary.com/examples-of-wind-erosion.html

​Erosion from water: 

Erosion from wind: 

In order to avoid wind erosion, some areas have wind blocks. Wind blocks could be fences, walls, or even trees that help reduce the wind’s strength.


Here’s an example of a fence with a wind screen. Although wind can still pass through the screen, it drastically reduces the wind’s power.

How do builders know what will withstand the wind? Not all structures are created equal! Engineers have to think very carefully about how they construct walls or wind blocks based on the location’s climate. Today your task is building the strongest wall possible that will withstand the wind.


Think about different walls that you’ve seen. What makes them strong?


What can you do to design a wall that will withstand the wind?


YOU WILL NEED:
* An electric fan
* Foam board (1/2 inch, 1 inch, and 1 1/2 inch thicknesses)
* Tape
* Mesh screen
* Utility knife (be careful!)
* Hot glue gun (optional)


Here’s what to do!
1. Set up a fan on a flat surface.
2. Mark a spot about 3 feet away from the fan with a piece of masking tape. This is your wall testing spot. You will test each wall you design on this same spot.
3. Test your control (the original wall with which you will compare your own design). The control is a plain piece of 1/2 inch foam board with no alterations. Set the control wall on the testing spot. Turn the fan on. Start at low, then turn it to high. What happens? You probably saw that a plain, thin foam wall was not enough to withstand the wind from the fan.
4. Test out the other thicknesses next. Does the thickness of the wall improve the strength?
5. Things to think about: Aside from thickness, what other alterations can you make to create a stronger wall? What if you create slats or cut holes in the wall? Will this make the wall more likely to withstand the wind? How can you create a wall that withstands the wind but also protects the area behind it? How could you use the mesh screen to create wind block?
6. Sketch your idea for your wall.
7. Use your materials to create a wall that you think will best withstand the wind while also protecting the area behind it.
8. Test your wall. What happens? Did it survive the low setting on the fan? Turn it up to high. Is it still standing? If so, great job! If your wall fell down, don’t worry! Just go back to the drawing board and redesign.
9. Continue to test and redesign until your wall survives the wind test.




For other windy day science activities, check out one of our other blog posts to learn about windchill AND make a wind-powered car:

http://www.discoveryexpresskids.com/blog/windy-day-science-measure-windchill-and-create-a-wind-powered-car


Although wind can be destructive, it can also be a great source of power! Learn more here from these wind energy facts:

http://www.sciencekids.co.nz/sciencefacts/energy/windenergy.html


References:

http://www.sciencebuddies.org/science-fair-projects/project_ideas/CE_p014.shtml#summary

Author: Maddie Van Beek

This week in Fargo has been incredibly windy! Instead of complaining, let’s embrace the wind and do some windy-day activities! 


What is wind? Another word for wind could be gust, breeze, or gale. Dictionary.com defines wind as air in natural motion that moves along the earth’s surface.


Listen to Hank Green’s explanation of wind in this video to find out more:

Now that you’ve watched the SciShow episode on wind, write down your definition of wind in your own words. 


Follow-up questions:

1. How is wind created? 
2. What is the point of wind? (Hint: What is wind trying to create/help the surrounding area reach?)
3. How is wind destructive? 
4. Can wind be a good thing? 

Wind as power
Although sometimes wind can be a nuisance, it can actually help us, too. Click the link below to learn more about how wind can be used as a source of renewable energy. Take the quiz at the end to check your understanding. ​

Now that you know how wind is created and how it can be beneficial for us, let’s analyze what wind does to the air around us. 


Windchill
How does wind affect the temperature? That’s kind of a trick question. Wind doesn’t actually change the air temperature, but it does make the temperature feel colder than it actually is. If you’ve lived in the midwest, you’ve probably heard a lot about windchill. Windchill is a temperature that conveys what the air around us feels like due to the wind. Wind makes the air feel colder than it actually is. The windchill temperature is always lower than the actual air temperature. Windchill is noticed more in cooler climates during colder temperatures. 


Now that you understand a little bit more about what wind is and how it is created, let’s move on to our activities for today. First, you are going to compare the temperature versus the windchill and create a visual for comparison. 


YOU WILL NEED:

• A computer with internet 
• Paper
• A red pencil and a blue pencil 

Here’s what to do!

1. Check the temperature, windchill, and wind speed and write down each in the chart. You can use weather.com or any other weather website. Make sure you’re checking the weather in your city or town! When you record your findings, use the chart below for reference.

2. Create a graph. The X-axis should be the date, and the Y-axis should be the temperature. Each day, you will check the temperature and the windchill at the same time. If you check the temperature and windchill at 8am on Day 1, continue to check the temperature and windchill at 8am each day. Use the graph below as an example:

3. Create a graph to show the temperatures you record. Use a red pencil for temperature and a blue pencil for windchill. 


4. At the end of two weeks, analyze your graph. When was the temperature and windchill most similar? When was it the furthest apart? Did stronger winds affect the windchill more than lighter winds? What about the direction the wind was coming from? 


For your second activity, you are going to build your own wind-powered race car! 


YOU WILL NEED:

• Plastic straws or coffee stirrers
• Popsicle sticks
• Lifesavers
• Scotch tape
• Aluminum foil
• Coffee filters
• Tissue paper
• Plastic wrap
• Stopwatch

Here’s what to do!

1. Think about a car. What are the most important parts of a car in order for it to function? 
2. The car you’re making today won’t have a motor and it won’t run on electricity. It’s going to run on wind! In order to make the most of the wind energy, you will need to create some sort of wind-catcher or sail for your car. Think about the materials that would work best to catch wind. 
3. Use paper and pencils to make a sketch of your car. 
4. Select the materials you would like to use for your car. Use the plastic straws or stirrers for the axles, and use the Lifesavers for the wheels. Other than that, use your imagination to construct the best car possible! Your car doesn’t necessarily have to look like a car, but it needs to be able to roll, and it needs to be able to be moved by wind. If you need a little help, check out the image below as an example. ​

5. After you’re done building, test it out! Take it outside to see if your car will roll with the wind. If it’s not windy outside, just use your breath. If your car does not roll, take it inside and make adjustments. 

6. Once you have a car that rolls, use the stopwatch to time how long it takes to roll 10 feet. Can you make it go any faster? Have your friends build cars and race them!

​7. After you’re done racing, analyze your results. Which materials worked best for the wind-catchers? Why do you think that is? 



References
http://stem-works.com/external/activity/199
https://www.teachengineering.org/view_activity.php?url=collection/cub_/activities/cub_sailcars/cub_sailcars_activity1.xml
https://en.wikipedia.org/wiki/Wind_chill

Author: Maddie Van Beek

Today we are going to learn more about simple machines. Last week we focused on the lever. You learned about levers by creating a ping-pong ball launcher and testing different kinds and positions of fulcrums. 


If you missed it, check it out here: http://www.discoveryexpresskids.com/blog/levers-and-launchers


Reminder, a lever is: A simple machine that contains a beam and a fulcrum. 
A fulcrum is: The point at which the beam of the lever rests and pivots. 


Examples: A seesaw, scissors, chopsticks. Can you think of more? 


This week, we are going to test out an inclined plane. Before we learn about inclined planes, let’s review what a simple machine is. 


A machine is...
-something that makes work easier for us. 


Work can be defined as...
-the force acting on an object in the direction of motion. 
-force times distance. (Work = Force x Distance)


Work sometimes is too great for humans to complete on their own, so we use machines to help us with that work.


A simple machine could be any of the following: 

• Wheel and axle
• Lever
• Inclined plane
• Pulley
• Screw
• Wedge

Read more about the six simple machines that make work easier at http://www.livescience.com/49106-simple-machines.html.


Check out this video for a quick explanation of what an inclined plane does for us: 

Follow-up questions:
1. What is another word for an inclined plane?
2. How does an inclined plane make work easier for us? 
3. When would an inclined plane be useful?
4. What is mechanical advantage? 


Can you think of an inclined plane that you’ve seen in real life? Here’s a few examples: ​

Author: Maddie Van Beek

Today, we are exploring the concepts of levers and fulcrums. You are going to create a simple machine that contains both a lever and a fulcrum--a ping-pong ball launcher! Before we get started, you need to know a little bit about what a lever is and what a fulcrum is.


First of all, what is a simple machine?


Think about what a machine does. There are so many different machines out there, but the main purpose behind machines is that they make life easier for people. Simple machines make work (the force acting on an object in the direction of motion) easier for humans to complete.


A simple machine could be any of the following:


* Wheel and axle
* Lever
* Inclined plane
* Pulley
* Screw
* Wedge


Read more about the six simple machines that make work easier (http://www.livescience.com/49106-simple-machines.html).


The simple machine you’re creating today is a lever.


A lever contains both a beam and a fulcrum. The fulcrum is the pivot of the lever. Think about levers in your everyday life. When have you seen a lever? One example is a seesaw... the bench that the two people sit on is the beam, while the center piece holding the beam in place is the fulcrum.

Fulcrum: The point at which the lever rests, is supported, and pivots.


Lever: A bar or beam resting on a pivot. Pressure (force) is applied to one end to help move an object (load) on the other end.


Check out the diagram of a lever below. You can see the beam resting over a pivot, which is the fulcrum. When you think of the ping-pong ball launcher you are about to create, the force will be you pushing down on the lever, and the load will be the ping-pong ball.

Now that you know a little bit about levers, you can get started on creating your own!


YOU WILL NEED:
* Plastic cup
* Ping-pong balls
* Wooden yardstick
* Tape
* Variety of fulcrums (thick book, shoe box, coffee can, log, etc.)


Here’s what to do!
1. Tape a plastic cup to one end of the wooden yardstick. Make sure you use lots of tape so the cup stays put! Your finished product should look like the shape below. The base of the cup is taped down, and the mouth of the cup is facing up. This is your ping-pong launcher!

2. Select your first fulcrum.
3. Set your your ping-pong launcher over the top of the fulcrum. The launcher should lean to the side over the fulcrum like the shape below.

4. Place the ping-pong in the plastic cup on the lower end of the launcher. Make a prediction, how far do you think the ping-pong ball will fly?
5. Quickly press down on the top end of the launcher to send the ball flying! Use a tape measure to check how far the ping-pong ball traveled. Repeat this five times and record your results each time. After the fifth launch, find the average launch distance. Do this by following the formula below.


Launch 1 + Launch 2 + Launch 3 + Launch 4 + Launch 5 = Total launch distance


Total launch distance / Number of launches


Total / 5 = Average Launch distance


6. How might changing the position of the fulcrum change the launch distance? Try moving the fulcrum closer to the launch cup.

Repeat step 5. What did you notice about the launch distance?


7. Try moving the fulcrum further away from the launch cup. Repeat step 5. What happened this time?

8. Record your conclusion. Which position launched the ball the furthest?


Extension: Now that you know which position works best, try using different fulcrums! Do different sizes or shapes affect the launch distance? Repeat the activity with at least two other fulcrums to determine which works best.


References:
http://buggyandbuddy.com/science-kids-launching-ping-pong-ball-snowmen/
http://www.livescience.com/49106-simple-machines.html

Engineering is something we hear a lot about these days.  There are engineers for buildings and bridges, cars and air planes, medicines and computers.  Engineering is one of the oldest professions; we hear about the engineers that built the pyramids of ancient Egypt, and the Pantheon in Rome.  Clearly it is a diverse and important field...but what exactly is engineering?

The American Engineers’ Council for Professional Development (ECPD) defines engineering thus:

“The creative application of scientific principles to design or develop structures, machines, apparatus, or manufacturing processes, or works utilizing them singly or in combination; or to construct or operate the same with full cognizance of their design; or to forecast their behavior under specific operating conditions; all as respects an intended function, economics of operation or safety to life and property”

~Engineers’ Council for Professional Development (1,2)

That’s a pretty complex definition!  What this really means is that engineers design, build, and operate many different things in our world, and try to find ways to make those things better.  Some of these things include buildings, roads, machines, and even processes (like the process for building a car). 

Because there are so many different things an engineer could do, engineering as a field is divided into many different types.  Below are just a few of the different types of engineering. 

Because engineers are always designing and building new and progressive things, and because they are always trying to improve what we already have, they often face great challenges.  In fact, the National Science Foundation announced in 2008 what are considered the 14 greatest engineering challenges for the 21st century (3).  One common thread between many of these challenges is finding the right resources and tools; some of the tools needed probably haven’t been invented yet, but others are simply too expensive or too rare to be economical.  For instance, solar energy has great potential to solve much of the world’s energy needs, but many of the materials needed to build the cells that capture solar energy are hard to come by (3). Because getting the right materials for a job is sometimes challenging, engineers frequently must build with what they have available.

CHALLENGE: BUILD A BOAT OUT OF PAPER!

Engineers use not only scientific information to design things, but also their practical knowledge and understanding of the society they work in.  So, what do we already know a boat needs?

1. It needs to be waterproof, so they don’t leak.
2. It needs to float.  This sounds simple, but it means the boat must displace (push away) an amount of water equal to its weight (please visit our blog on buoyancy for more information!).  This is what makes the shape of a boat so important. 
3. It may need to transport cargo.  This could be people, or objects, or both!  This means they must be durable, and they must displace even more water when something else is placed in them. 

Most boats are made of aluminum; some very large boats, like huge cruise ships, are made of steel.  But if you put a solid piece of aluminum or steel in water, it will sink!  So how does a boat float?  Think about the shape of a typical boat.  What do you notice?  It is this shape that allows the boat to displace its weight in water, so it can stay afloat.

Here’s what you need:

1.       Paper!  Any kind of paper will do—newspaper, magazines, scratch paper from a copier; just make sure that no one needs the information on the paper!  Getting some from a recycling bin would be best!

2.       Other things to build your boat with.  Be creative!  Think about what your boat needs to have in order to float and not leak.  Here are some suggestions as to what else you might want to use:

            a.      Waterproof tape.

            b.      Glue

            c.      Thin wire or flexible sticks

3.       Some small object that is heavy for its size, like a small rock.

4.       A bathtub or sink full of water.

Here’s what to do:

1. Plan!  Write down how you plan to build your boat using the materials provided.  ONE OF THE MATERIALS YOU USE MUST BE A PAPER PRODUCT!
2. Assemble your boat . 

   3.       Put your boat in the bathtub or sink full of water for 20 minutes, with the heavy object inside.  The boat should be able to stay afloat for 20 minutes without any water getting in.

What happened?  Did your boat float?  Did it keep water out for the whole 20 minutes?  Could it hold the heavy object?  Do you think you could improve your design?  Write down what happened and how you might improve your boat in your journal.  Try building your boat again, and see if you can make those improvements!  See if you can make your boat float longer!

For further reading, check out these sites!

Ancient Egyptian Engineers: http://www.history.com/images/media/pdf/engineering_empire_egypt_study_guide.pdf

Ancient Roman Engineers:  http://www.historylearningsite.co.uk/roman_engineering.htm

Types of Engineering:   http://www.aboriginalaccess.ca/adults/types-of-engineering


References:

1)      Engineers' Council for Professional Development. (1947). Canons of ethics for engineers

2)      Engineers' Council for Professional Development definition on Encyclopædia Britannica (Includes Britannica article on Engineering)

3)      Cooney, Michael (2008).  “What are the 14 Greatest Engineering Challenges for the 21st Century?”, Network World, www.networkworld.com.

4)      Maehlum, Mathias Aarre (2014). “Solar Energy Pros and Cons.”, Energy Informative, www.energyinformative.org.


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Today if you find you are lost, you can usually just pull out your GPS (Global Positioning System) to find out exactly where you are, and find exactly where you want to go.  Many cars and nearly every cellular phone have GPS units or apps to use for finding your way.  But the GPS system didn’t become fully operational until 1995.  People have needed to find their way for hundreds of years!  What did people do before GPS to find where they were going?

Throughout the years humans have used a number of methods to find their way (that is, to navigate) to their intended destination x.  Hundreds of years ago people would use known landmarks, or the position of the sun, moon, and stars to decipher where they were.  Beginning about the year 1040 AD, the Chinese began using the compass for navigation1.  A compass (in this case, a magnetic compass) is simply a small magnetized needle or bar which is balanced on a point on which it can easily pivot or spin.  This magnetized needle will pivot on this point such that one end of the needle points toward North.  Generally this end of the needle is painted red, or otherwise indicates to the user which way is North.  Using this simple device, human beings of the ancient world were able to cross oceans and continents, and .find their way home again.

Why does Earth have a magnetic field surrounding it?  Recall that magnetic fields are created by the movement of charged particles (see our most recent blog about magnets and magnetism).  Scientists believe that Earth’s magnetic field is created by the movement of hot liquid and crystallized iron at its core2.  As the Earth revolves on its axis, the molten iron at the core—and thus the electrons in the iron—are also rotating.  These rotating electrons are what create the magnetic field.

TRY MAKING YOUR OWN COMPASS!

Here’s what you’ll need:

1.       A needle or other thin, lightweight piece of steel

2.       A Styrofoam cup

3.       A scissors

4.       A glass pie plate

5.       A strong bar magnet (good ones are available from eBay and Amazon.com, but you can always try your local hardware store)

Here’s what to do:

1.       Fill the pie plate with water from your kitchen sink.  Place the plate on a flat surface.

2.       Carefully cut the bottom off the Styrofoam cup using your scissors.  Be sure not to leave any of the cup edges.

3.        Magnetize your needle:  take the strong bar magnet and rub one end of it along the needle in only one direction at least 20 times.  This will align the atoms in the needle, causing it to become magnetized.  You can check to make sure your needle is magnetized using a few paper clips; if the needle will pick up the paper clips, it’s magnetized!

4.       Carefully place this needle on top of the disc of Styrofoam you cut from the cup earlier.  Float the Styrofoam with the needle in the pie plate of water.  The needle will slowly turn to point North!
What did you observe?  Did your needle point North?  Did it stay this way?  Be sure to write down all your observations!

CHALLENGE YOUR FRIENDS TO A TREASURE HUNT!

Hide a flag in a tree or in some tall grass.  Make up a map to the object telling your friends how many feet or steps North, South, East, or West they should go from where they start.  Then provide them with all the things they need to make their own compass to figure out which way is North!  This works when the area is not very familiar, so going to a State Park or wooded campground would likely be a good location.

References for further reading:

1.            Lowrie, W., Fundamentals of Geophysics. 2nd ed.; Cambridge University Press: Cambridge; New York, 2007.

2.            Brain, Marshall.  "How Compasses Work"  01 April 2000.  HowStuffWorks.com. <http://adventure.howstuffworks.com/outdoor-activities/hiking/compass.htm>  28 May 2014.

Magnets are everywhere.  From the small decorative pictures on your refrigerator to the giant cranes that separate metals in junkyards, magnets are found in many places and come in many shapes and sizes. 

But just how does a magnet stick to your refrigerator door, or to the metal in the junk yard?  What is a magnet, and how does it work?

A magnet is simply anything that produces a magnetic field.  It is this invisible magnetic field which allows the magnet to “stick” to some types of metal, like iron and steel.  We often see the magnetic field of a magnet represented as lines leading from one end of the magnet (the North pole) to the opposite end of the magnet (the South pole). 

While these magnetic field lines are invisible, you can see them by putting small pieces of iron metal  (also called iron shavings or iron filings) on a white sheet of paper, and placing the magnet beneath the paper.  The pieces of iron will align themselves along the magnetic field lines!  If you can find some iron filings (which you may be able to get from a metal working shop), try this with a bar magnet (that is, one that is a straight bar or tube)!

Magnetic fields are created by the movement of electrically charged particles, such as electrons (one of the building blocks of the atom).  This movement of electrons can be a permanent quality that comes from the material the magnet is made from, like a refrigerator magnet.  These are therefore called permanent magnets.  This movement of electricity can also be induced using electricity.  Let’s say you have a piece of wire, and you connect it to a battery.  The battery will produce an electric current in the wire—that is, it will cause electrons to flow through the wire.  The movement of electrons through the wire will create a magnetic field around it.  Because this field has been induced by electricity and will stop once the battery is disconnected, it is called an electromagnet (this type of magnet will not be a magnet once disconnected from the battery). 

Since we know that the flow of electrons through a wire will create a magnetic field, and we know that this magnetic field is what causes some metal objects to stick to a magnet, we should be able to make our own magnet using a battery and wire, as in the previous example. 

TRY THIS!

Here’s what you’ll need:

1.       One 9-volt battery

2.       Three feet of thin copper wire

3.       Electrician’s tape (usually thick, black, stretchy tape)

4.       One three inch steel, galvanized nail (not stainless steel or aluminum)

5.       Several paper clips (metal ones, not plastic ones!)

Here’s what to do:

1.       Wrap the copper wire around the nail as tight as you can, at least 50 times.  Leave at least 4 inches of wire hanging off each end of the nail.

2.       Make a small hook at each end of the wire. 

3.       Use the hook at the head end of the nail to hang the wire onto the positive terminal of the battery.   The end of the wire should touch the inside bottom of the terminal.  Secure the wire firmly in place with electrician’s tape.

4.       Use the hook at the point end of the nail to hang the wire onto the negative terminal of the battery.  The end of the wire should touch the inside bottom of the terminal.  Secure the wire firmly in place with electrician’s tape.

5.       Hold onto the wires, and move your nail close to the paper clips.  The nail should now pick up the clips like a magnet! 

NOTE:   Use caution here, because the battery will get hot!! 

Did your magnet work well?  How many paper clips could you pick up? 

MAKE UP YOUR OWN EXPERIMENT!

Connect more than one battery together, and see how many paperclips you can pick up!  Just connect the head end of the nail to the positive terminal of one battery, and the point end of the nail to the negative terminal of the other battery.  Then cut a small piece of wire to connect the open terminals of the two batteries together.

Try using a 12-volt battery instead.  How many paper clips do you think your nail will be able to pick up?

Try using a longer nail, or a larger piece of steel. 


References for further reading:

1)      Magnet.  Wikipedia.  2014, Apr 26.  Retrieved 5-20-2014.  (http://en.wikipedia.org/wiki/Magnet)

2)      Magnetic Field.  Wikipedia.  2014, May 22.  Retrieved 5-22-2014.  (http://en.wikipedia.org/wiki/Magnetic_field)

3)      How Magnets Work.  HowMagnetsWork.com. Retrieved 5-21-14.  (http://www.howmagnetswork.com/)


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