Wednesday, October 31, 2012

Happy Halloween!

From the doctor and the scientist, may you have a safe and Happy Halloween!

Tuesday, October 30, 2012

Kid friendly pumpkin carving

J's at an age where all of the holiday traditions start becoming fun! I really wanted him to get into pumpkin carving, but I wasn't sure of the knife aspect of pumpkin carving. Flashback ~8 yrs ago, my roommates and I found these cute pegs for pumpkins, Fright Lights; think Lite Brites but for pumpkins. I don't think I ended up with the pegs, but I bought new ones just in time for Halloween.

J's excitement builds as we open the pumpkin
Science time, how does that feel J?

Ewww, gooey!

J's turn to feel the pumpkin guts

Pumpkin's clean, now time to tape on the pattern and poke holes, which will be used for hammering in the pegs.

Hammer time!

Almost done. Instead of whacking every which direction, J figures out he can press really hard on the hammer against the pegs. It worked well!

The finished product (the pattern came with the pegs)

Kid friendly pumpkin carving

The happy carver!

Halloween light lesson: opaque, translucent, and transparent.

Pumpkins are opaque. Without carving them out, if you shine a light on them, you can't see the light through the other side of the pumpkin.

Light Pegs are translucent. Translucent items let some, but not all, light through. Another good example of this is a frosted glass shower door.

The carved part of the pumpkins are transparent. Light shines through transparent items, unblocked. Windows and clean glass are great transparent objects.

What happens if you change the quantity/quality of light?
Is it easier to see the pumpkin with the lights on/off?
Before carving, stick your lighting source in the pumpkin to see if you can see it. Can you see it when the lights are on or off?
How does the inside of a pumpkin feel?

Unplanned science lesson while prepping for the holidays? Check!

Happy Halloween!

Monday, October 29, 2012

Science Saturday - Pumpkin Catapults

This was the last Science Saturday of 2012 (mainly due to holidays), but it was fun to go out with a bang! Thanks to the families that came out! We had a beautiful morning in the park.  I took some pictures of our friends and the craziness of having 10 catapults shooting at the same target, but I haven't gotten permissions from parents to post. Here's the non-identifiable rundown.

I took 10 minutes the night before to cut and paste some Halloween themed characters made out of construction paper onto the back of a 36-pack of Diet Pepsi (ya, I haven't quit my drinking habit) and made some arbitrary point system that the kids loved! Who doesn't love scoring 50 points vs 25 or 10? Yay, math!

And I arbitrarily set up three cones, which the kids moved throughout the day. As long as they were having fun, learning science, and not bored, I didn't really care where they shot their catapults from.

I covered a paper box with construction paper and drew a spider web to hold our ammo.

Here's our ammo of various sizes and weights; we also used candy corn pumpkins:

Big J and I spent the week before gluing sets of 3 Popsicle sticks together to use for the catapult structure and 5 Popsicle sticks for the launching stick, using wood glue - white glue works well too (both have to dry for ~24 hrs before applying load/playing). Catapult directions (note we only used 3 sticks instead of 4 for the structure sides to save Popsicle sticks and time and it worked well). Since we do these events at the park and there are times little kids grab things that are hot (be it knowingly/unknowingly), I invested in some Ultra Low Temp Battery Power Glue Guns. They worked well for the two hours we needed them. They use a lot of their "special" type of expensive glue sticks, but we didn't have burns or complaints. The batteries also pop out really easily, so I'd recommend taping the battery case shut. Also, since the glue doesn't do a great job (just a so-so job), I'd recommend reinforcing what you glued with masking tape.

Big and Little J launching pumpkins. Little J being a tad bit over dramatic.

A friend playing the target game.

We only had one friend who ventured outside of the example catapult design. He modeled his new design off of one Big J had 3D printed and brought to the event. I love it when kids challenge themselves.

Remember the science behind catapults? It's the transfer of energy, from elastic energy (which is a form of potential energy - it will potentially do something once you let go after stretching it) to kinetic (a fancy term for motion) energy.

Humans also need energy to "go" - can you name how we get our energy? Hint, it's not elastic.

Thursday, October 25, 2012

Pressure and water painting

Big J pulled this from the same book as our modified penny in a cup, surface tension experiment, Science Play by Jill Frankel Hauser, but again, we modified it for our family. Being not big into messes (and having a somewhat mischievous boy), we don't stock paint in the house. However, we have TONS of construction paper, and water "paints" very well on construction paper.

Hand prints using water on construction paper
The objective of this lesson was to demonstrate pressure and see what it does to water. Big and Little J put a large drop of water on the construction paper and blew through a straw to see how the water reacted. We noted the direction of the water spray.

Then Big J decided to put two similar sized dots of water on the construction paper (close to his hands).

He gave the one on our right (his left) a little blow (barely blowing) and blasted the one on our left (his right) with a big blow. Can you tell how the water drops reacted to his experiment?

J gave it a try too.

Then he decided water painting was much more fun. Yay, for construction paper absorbing water!

Tuesday, October 23, 2012

Happy Mole Day!

What kind of science loving nerd would I be if I didn't wish you Happy Mole Day!  Too bad it's a little late.  Maybe I'll be more on top of my game next year.

On Mole Day, we celebrate Avogadro's number, which is 6.02x10^23.  Some people celebrate it at 6:02 in the morning of 10/23.

What is a mole? It's a unit consisting of 6.02x10^23 somethings (that's a lot of somethings!).

In 10th grade chemistry, we celebrated by making cute little moles (see above).  Mine was Super Mole, but just recently lost his cape after he became a toy for the 3-year old.  He saved the world 6.02x10^23 times, if I remember right.  I also made a Mole Kent who had a super awesome telephone booth where he changed to become Super Mole.  My little sister reincarnated Mole Kent to Whoopi Moleberg, who was then saved by her chemistry teacher (not sure what her mole consisted of - remind me, Julie?).

What's the whole point of Mole Day??  To remember the number!  10/23 falls relatively early in the school year, and it's a number chemistry students frequently need to use, so it works very well.  I can still state the number 15 years after celebrating my first Mole Day.  Thanks, Dr. Mr. P (my high school chem teacher)!

There's no real set way to celebrate.  We made cute moles and gave them stories.  I hear a lot about eating guacamole on Mole Day (but we're picky eaters and green paste isn't on our list of things we eat).

How do/did you celebrate Mole Day?

Monday, October 22, 2012

Water surface tension - pennies in a cup

Note: We got the idea for this experiment from Science Play book by Jill Frankel Hauser.

I grew up with a scientist mom, and her favorite experiment was the drops of water on a penny to analyze surface tension of water. That's a little too hard for my 3 year old to do (I remember being somewhere around 7 for those experiments). So when I found the experiment with placing pennies in a cup of water, I figured it would work for J.

Now, being a scientist myself, I had questions of my own that weren't answered by the book, like how does temperature affect surface tension of water? I decided that could be our experiment.

To complete the experiment, I filled up clear plastic glasses with different temperature water (cold water from our fridge, cold water from the sink, hot water from the sink - ours comes out really hot!) almost to the top of the glass. While the glass was on the table, I used a clean medicine dropper to fill the glass to the brim. We started gently adding pennies, one at a time waiting for the water surface to be calm before we placed another one on there.

The set-up

Water careful filled to the brim

The adults showed J how to do it.

J was so excited to do it himself, but three year olds aren't super careful and like when things splash.

Gently add pennies 1 by 1

In general: as temperature increases, surface tension should decrease (making it harder to stick together). Our hypothesis (educated guess) was that the colder glasses of water would hold more pennies.

Our results:

Cold glass: 26 pennies (J)
Room temp glass: 25 pennies (Big J)
Hot glass: 18 pennies (Mommy)

Things to discuss:
*What shape does the water make after adding pennies?
*How many pennies did you get into the cup before it spilled?
*How did the temperature affect the surface tension in your experiment?
*Which cup of water held the most pennies?
*Repeat the experiment with different liquids (ex. juice or isopropyl (rubbing) alcohol -under extremely close adult supervision). How do the different liquids act when the pennies are placed in them? Why do you think that is?

Things that could have affected our results:
*Cups might not have been filled to the same levels.
*We didn't place the pennies in gently enough, causing a splash.
*Pennies weren't fully dry between cups (adding more water).
*Someone could have accidentally bumped the table (it happens with a three year old).
*Pennies had various amounts of dirt on them. A piece of grass ended up in the cold cup, which could have affected the experiment.
*Each person did pennies in a different glass. Ideally, we would repeat the experiment with the same user for all three glasses, but we're not that patient around here and everyone wanted a turn.

Happy experimenting!

Monday, October 15, 2012

Renewed interest in space

Last night, J pulled out his space pajamas that had found their way to the bottom of his drawer.

J: I'm going to jump out of the spaceship!
Me: Mommy will not let you jump out of the spaceship.
J: Why?
Big J: Mommy was pretty nervous about watching someone she didn't even know jump out of the spaceship.
I'm thankful that my son is excited about space and science.  I'm sure we'll be watching Youtube videos of the jump over and over again for the next few weeks, and maybe find something else in the process.

Check out the information from the Red Bull Stratos page to learn more about this mission and the cool things that went down.  The gallery offers some valuable, easy to understand explanation of the science.

Sunday, October 7, 2012

Pumpkin Catapults

We're testing the waters for our fun Halloween Themed Science Saturday in the Park and launching candy corn pumpkins via a home made popsicle stick catapult.

I made this catapult lesson for an outreach event for middle school girls.  The main concept: transfer of energy.  Energy is stored as elastic energy (a form of potential energy) when you pull down the catapult arm. When you release, the energy is transferred to kinetic (fancy word for "motion") energy.  If you pull down further, more energy is stored (be careful though, the sticks may snap) and the item should go further and faster in ideal conditions.

J launching a pumpkin
Catapult Assembly:
*Glue or masking tape 4 popsicle/craft sticks together - lay two sticks end-to-end and glue one stick on top so it is glued to both sticks, flip it over and glue one stick on the other side.
****Please use caution when using hot glue around kids.  You can white glue them for a better bond, but you'd have to let them sit/dry overnight.****
*Repeat the stick assembly from above 5 times, so you have 6 total longer sticks.
*Assemble 3 of the longer sticks you just created (from above) to form the base - a triangle (a good and strong shape).  Glue/tape the corners together.
*Take the remaining 3 longer sticks and glue them to each corner and gathering on top (forming a pyramid shape).
*Catapult arm assembly: glue/tape 5 popsicle/craft sticks together three on the bottom, end-to-end and two on top.  Flip over after gluing so the 3 sticks are on top.  Glue a Dixie cup (to go salsa containers can work well too) to one side of the catapult arm.
*Take a rubber band and loop it around the top of one of the catapult sides using a girth hitch knot.
*Stick the arm of the catapult through the rubber band and glue/tape it to one corner of the base (we both glued and taped).
*Stick launching item into the cup, pull back on the catapult arm and release.

Launching items:
*Candy Corn Pumpkins!
*Bite sized candy bars - great because you can launch many times, unwrap and eat
*Gummy fruits
*Uncooked beans
*Small softer toys
Warnings: I don't recommend harder objects like rocks, at least indoors.  Also, make sure the flight path is clear from all faces (including the launcher).  Eat unwrapped, launched candy at your own risk.

Science play ideas:
*How far can you launch your item?
*Try different sized items.  How do they compare?
*Try multiples of the same item.  How do they compare to your first launch of only one of that item?
*Try releasing the catapult arm at different heights.  What happens if you release close to the top of the catapult vs. when you pull it all the way down to the ground?
*Play a game where you hit targets.
*Try different rubber bands (you can always stretch them over the cup to attach to the catapult arm).  How does the rubber band affect your catapult?
*What happens if you don't hold down the front of your catapult while you try to launch your item?

This is what we'll be doing for Science Saturday.  Come join us if you can!  Shoot me an email, and I'll give you more specific details.

Related Posts:

Friday, October 5, 2012

Save the Date - Science Saturday, Halloween Theme

Save the date for the next Science Saturday in the park.

Sat. Oct 27, 2012
SF Bay Area
Park location to be given upon RSVP

I'm in the planning stages and need to test-run my ideas, but I'm excited about it!

It'll involve fun science and prizes.  Kids could come in their Halloween costume, as long as they have their face showing (ie no masks, it might interfere with the project) since I like the idea of using a costume more than one night during the year.  I might even have prizes for the nerdiest costumes.

Are you excited yet?

Monday, October 1, 2012

Science Saturday in the Park: Elbows and Muscles

Wow, we had quite a turn out this Saturday to learn about elbows and muscles.  Thanks everyone for coming!

I repeated the Elbows and Muscles lesson I did at Kid's Day since I had leftover material (and it's a fun one!).  The detailed instructions on how to make the elbows are here: younger kids elbow lesson, while the more advanced lesson can be found here: middle+high school elbow lesson.

Since the science days are attended by neighbor hood preschool aged kids, I decided to add a new trick to help with conceptualizing how muscles really work.

I tied a string to a rock.

I then asked the kids to move the rock with the string (9 times out of 10 they intuitively pulled the string towards them).  I then asked them to push the rock to me using the string.  It never worked!  Strings don't push, they only pull.

Then if I still had their interest, we continued on to making elbow models (lessons described in the above links).  Some kids, depending on their interest level, got anatomy lessons about the bones and muscle names (major muscles: biceps (flexion/bending), triceps (extension/straightening); arm bones: humerus (upper arm), radius and ulna (lower arm)).  We also brought up tendons, which attach muscles to bones (our string muscle was attached to our ruler bone with a paperclip "tendon").

One participant had an awesome question about making a punching motion.  Punching motions use more than one joint!  I discussed the way the shoulder moves (many, many degrees of freedom) that helps you raise your arm forward and pull it back, combined with the bending/straightening of the elbow (+rotational degree of freedom of the radio-ulnar joint) helps you punch.  To model this, you would need two more joints on top of the basic flexion/extension elbow we just made.  Your body has many muscles, bones, and joints that work together as a team to move you in the way you'd like to move.

P.S. To the parents: I don't endorse nor did I come up with the idea of the karate chopping elbows.  Sorry if your kids have figured out they can sock their sibling with the elbow model.

Link to bulk purchase of rulers: Charles Leonard Inc. Ruler, 12 Inch, Wood, 36 rulers