Friday, January 30, 2015

Pasta and Marshmallow Towers!

Here's a fun way to learn about a fundamental part of engineering -- compression and tension:

What you need:
30 small marshmallows
20 unbroken, uncooked long pasta
measuring tape
small books (as weights)

The goal is to build the highest and the strongest tower out of the pasta and marshmallows.  There are no step-by-step instructions for this project so feel free to be creative and test out different structures and different shapes

Suggested: Turn this into a friendly competition with your friends.  First see who has the tallest tower and then see who can build the strongest tower (which tower can withstand the most weight--this is where the books come in).  

What you will discover:
Different materials have different properties. You will see that the pasta cannot withstand much tension or compression which means it will break very easily, much more easily than a marshmallow. You will find that marshmallows are rather compressible but quickly break under tension.

Wondering how effective your structure is?
Put your structure on a cooking scale and record the weight.  Now divide the load (the amount of weight your tower can hold) by the total weight of your structure.  The higher the number this calculation gives you, the more effective your structure is.  Try different shapes for the structure and see which shape gives you the most effective structure. Happy building! 

Tuesday, January 27, 2015

Elephant Toothpaste! (experiment for ages 10+)

Warning: this is an experiment that you should only do if you are 10 or older! You can also only do with the help of an adult, even if you are already 10 or older! 

If you aren't old enough to do the experiment or can't find an adult helper, that's ok! You can still watch this video where people make elephant toothpaste and explain how the chemical reaction in elephant toothpaste works:

If you're 10 or older and you have an adult helper, you can follow these instructions to make the elephant's toothpaste yourself!


  1. empty plastic soda bottle 
  2. ask an adult to get this for you: 1/2 cup 20-volume hydrogen peroxide (20-volume is 6% solution, purchased from a beauty supply store)
  3. squirt of Dawn dish detergent
  4. 1 teaspoon yeast dissolved in approximately 2 tablespoons very warm water
  5. funnel
  6. foil cake pan with 2-inch sides
  7. safety glasses
  8. lab coat or any clothing that covers your skin


  1. Put on the safety glasses and lab coat (or other protective clothes).  
  2. Stand the bottle up in the center of the cake pan. Put the funnel in the opening. Have your adult helper add 3-4 drops of food coloring to the peroxide and pour the peroxide through the funnel into the bottle. 
  3. Add the Dawn detergent to the peroxide in the bottle.
  4. Pour the yeast mixture into the bottle and quickly remove the funnel.
  5. Touch the bottle to feel any changes that take place.
  6. Record your observations.

Friday, January 23, 2015

GoldieBlox - You Build Your Toys

Everyone's played with toys before, but what about building your own? Step aside Legos, GoldieBlox is here to give you a taste of engineering with toys as the dessert. Besides being an awesome building set, GoldieBlox's goal is to "disrupt the pink aisle" and give young girls a chance to develop their engineering skills. Debbie Sterling, a mechanical engineering major from Stanford, wanted GoldieBlox to inspire the next generation of female engineers. Here are a couple of videos from GoldieBlox showcasing how much fun GoldieBlox can be:

GoldieBlox SuperBowl Ad

GoldieBlox & Rube Goldberg "Princess Machine"

Interested in purchasing a GoldieBlox product? Click here!

Tuesday, January 20, 2015

Design Challenges

Hey there, Tinkerers!

Ever wonder how satellites and spaceships are able to turn and change their paths in space? Check out this design challenge and see if you can do the same thing with magnets and a steel ball!

After you're done with the last one, here's another cool design challenge to check out. Try designing your own robotic arm to pick things up.

Let us know how it goes in the comments section! Did your design work? Or did you think of a better way of building it?  Maybe you used more than one magnet to steer your ball or different materials for your robotic arm. Try different things and see which design works best. Happy Tinkering!

Friday, January 16, 2015

Crazy Pool Vortex!

Check out this video related to fluid dynamics by Physics Girl on YouTube!

We highly recommend trying this experiment at home if you have your own pool!

Tuesday, January 13, 2015

Make Your Own Rock Candy

Got a sweet tooth? Then this is experiment for you!
NOTE: This experiment involves a stove and boiling water, so please make sure to take the proper precautions.

  • 3 cup of Sugar
  • 1 cup of Water
  • String or pipe cleaner
  • Pencil or stick
  • Paperclip
  • Tall jar or glass
  • Pot
  • Wooden spoon
  • Food coloring (Optional)
  • Flavoring (Optional)
  1. Twist or tie the string around the middle of the pencil and the paperclip to the other end of the string. Make sure the string is short enough that the paperclip is dangling above the bottom of the jar when the pencil is resting on top.
  2. Wet the string, roll it in the sugar and set it aside.
  3. Boil the water in the pot on the stove and when it starts to boil take it off the stove to settle.
  4. Add in the sugar a half cup at a time, mixing continuously until sugar starts to collect at the bottom of the pot even when you stir.
  5. Add in the food coloring and/or flavoring.
  6. Pour the mixture into the jar until it is about an inch from the top.
  7. Place the pencil over the jar with the string and paperclip hanging in the mixture.
  8. Set the mixture somewhere where it will not be disturbed (but do not refrigerate) and wait.
  9. In a day or so, you will start to see crystals start forming on the string. You can then leave the string in the mixture until the crystals have grown as big as you want or until they stop growing completely.
  10. Remove the string from the glass, dry your crystal and enjoy!
What Happened:
The crystals formed on the string because because the sugar mixture was a super saturated solution. This means that there was more sugar dissolved in the hot water than room temperature (or cold) water can hold. When the water cooled down, the sugar could not stay dissolved and "came out" of the solution. The sugar then adhered the the string which acted as a "seed" and sugar crystals formed. 

For more information check out:

Friday, January 9, 2015

Make your own Silly Putty!

Making your very own SILLY PUTTY!

Materials Needed:
-Elmer's Liquid Glue
-Sta-flo Concentrated Liquid Starch
-Food coloring

1.) Mix the food coloring into the liquid glue. Do this until the color is nice and even.
2.) Pour in the liquid starch.
3.) Stir and let it sit for about five minutes.
4.) Take the putty out of the bowl and knead in your hands for five to ten minutes.

***Aim for two parts glue and one part liquid starch***

And that's it!

Some more information about silly putty:
-it is a dilatant compound, or a gel that becomes solid under pressure
-more than 4,500 tons of silly putty have been sold since the 1950s
-the first silly putty was a mixture of silicone oil with boric acid

Tuesday, January 6, 2015

Make your own bicep!

Biomedical engineers try to understand how the body works so they can fix it with artificial parts when it gets damaged. One of the important types of body parts is muscle. When a muscle is stretched too much, or strained, it might need a biomedical device to get better. Sometimes a device can act like a muscle and help your strained muscles rest and heal faster. Try out this activity to make an artificial bicep!