Tuesday, October 22, 2013

Hot and Cold

This week we learned how to use a thermometer. First we measured some temperatures in and around the kitchen: the freezer, the fridge, room temperature, etc. Then we went out into the yard to find the hottest and coldest spots. We were surprised to find as much as a 5 °C difference between sunny and shady areas.

Slippery Slope

Which surface has the most friction with a coin?
To figure this out, we placed a coin on top of different materials, gradually raised one end of the material until the coin began to slide, and measured the angle using a protractor. The idea being, the steeper the angle necessary to get the coin moving, the greater the friction between the material and the coin. 

Next week we hope to apply our results to the larger question: What can you do to reduce the friction on playground slides? Let's hope for good weather!

Slime flies when you're having fun

How to make slime that has just the right consistency - neither too sticky, nor too watery?
It's all in the measuring...

Over the past few weeks, we've learned how to measure liquid volumes using a graduated cylinder, how to measure mass with the digital scale, and how to mix different colored water to make a rainbow of possibilities. This week we put these skills to good use making the ultimate SLIME! 

Thursday, October 17, 2013

Tipping the scales

Do you have too many skirt hangers lying around?

In the mood for cream of mushroom soup?

Wondering what weighs more: a daffodil bulb, a AA battery, or a vertebra from a wild bore*?

Then I've got the perfect DIY project for you!

This week we learned about mass. Each lab group built a scale using a skirt hanger with an empty mushroom package suspended at each end. We compared the masses of various small objects by placing them inside the baskets. Finally we checked ourselves using a digital scale.

* a daffodil bulb

The Tortoise, The Hare, and You!

Usain Bolt is unquestionably the fastest human alive, but how would he do if he had to compete against other species, like say a grizzly bear? In 2009 he broke the world record, running 100 meters in 9.58 seconds. That's faster than 10 m/s and around 38 km/h. This week we looked at some data on the maximum speeds of different animals and then tested our own local humans.

Most of us fell somewhere between a chicken and a pig.

Can you weigh and chew gum at the same time?

Did you ever wonder what happens to the mass of gum as you chew it?

To investigate this question we used a scale to measure the mass of the gum at one minute intervals. Now, I know what you're thinking...how does one chew gum and weigh it multiple times without being REALLY gross?!  Bubble gum wrappers make great weighing paper, so we just made sure to measure the mass of the gum in its wrapper before and after chewing it.  Still a little gross, but nothing our scientists couldn't handle.

After graphing the data we observed that the mass decreased, and surprisingly, it didn't happen at a constant rate. Most of the sugar was lost in the first 2 minutes, and after that there was relatively little change. After analyzing our results we wondered if bubble-blowing and talking might affect our results.

Friday, October 11, 2013

Water, water, everywhere!

When it comes to space exploration, nothing makes the news quite like the possibility of finding extra-terrestrial water. Just over a month ago,  a research team from Japan used the Subaru Telescope to observe the water-rich atmosphere of Gliese 1214 b, a planet 40 light years from Earth.

Why are we always searching for water in space? What does discovering water have to do with the possibility of discovering extra-terrestrial life? 

To begin answering these questions, we explored some of water's interesting properties through the following investigations:

Water's molecular structure: We made models of water molecules, noting how oxygen and the 2 hydrogens share electrons.

Water sticks to other water molecules and other stuff too: We observed the U-shaped water line in a graduated cylinder and the dome shaped water line, as you fill a cup just beyond the brim.

Water is strangely denser than its solid form, ice. 

Water's a great solvent: We saw how water dissolves marker ink and carries along its components through filter paper.

Finally we discussed why these properties are so important for life as we know it.

Un-mixing Milk

This week we tried 2 different ways to "un-mix" milk. The first way involved brute strength! We poured some heavy cream into a jar, and we shook it and shook it until it separated into a clear liquid and a creamy solid, better known as butter.  The second way we extracted solids from the milk was through a few chemical reactions. First we added some vinegar to the milk to curdle it. Then we separated the solid proteins using filter paper, and neutralized any extra vinegar with baking soda.  Finally we added a little water, resulting in our own home-made glue.  

From the Earth to the Moon

This week we got the following challenge: Apply Newton's 3rd Law: For every action, there's an equal and opposite reaction, to design a rocket that can travel from the earth to the moon, or at the very least, design a straw, souped up with just a balloon and tape,  that will fly along a string, tied between two chairs sporting pictures of the earth and the moon. We worked in teams designing, building, and rebuilding our rockets. We learned a lot through trial and error and were even inspired to brainstorm how to design a balloon rocket that would travel to the moon and back in one uninterrupted trip. 

What would you do?

Here in Israel, we've got some real heroes to inspire us. Yariv Bash, Kfir Damari, and Yonatan Winetraub are leading Israel's SpaceIL's team in Google's global competition to successfully launch, fly, and land a robotic spacecraft on the moon.

For some more background on their work, you can watch this BrainPOP video.

"We choose to go to the moon this decade and do the other things, not because they are easy, but because they are hard"(John F. Kennedy, 1961)

Thursday, October 10, 2013

Measuring Mass

This week we added the triple-beam-balance to our repertoire of measuring tools. First we discussed the difference between volume and mass, and then we worked in pairs guessing and weighing different objects. Finally we checked ourselves and the triple beam balances using a digital scale. We noticed that a) we measured pretty consistently, and that b) our triple beam balance was only off by about a toothpick. Not that big a deal, unless of course, you're measuring toothpicks!

So what do you think weighs more...a pound of gold or a pound of feathers?

Thursday, October 3, 2013

Etrog vs. Lemon

With the holidays just wrapping up, studying etrogs from a biological perspective seemed like a great way to kick off Science Explores aka Life Science. The etrog, more commonly known as the citron, belongs to the citrus family of flowering plants. Etrog trivia: The "pittom" is which part of the flower?1

Then we asked the question: Is an etrog simply an over-priced, funny-shaped lemon, or is there more going on?2 We made some external observations, noting their shape, color, volume, mass, and density. Then we opened them up and looked inside. Turns out, there are some interesting differences in the relative proportions of peel, fruit, and juice volume. We measured each fruit's pH, and then celebrated a job well-done to the tune of a tall glass of lemonade. Due to the lack of juice, the etrogade wasn't as successful.

"Flavedo" and "albedo" are
a. the yellow and white parts of the rind
b. trapeze artists, as in "The Amazing Flavedo and Albedo"
c. great scrabble words, well "flavedo" anyway

1. The stigma, the part that receives pollen grains
2. There's more going on 
3. a.

Tuesday, October 1, 2013

Go Speedracer Go!

It's just amazing what you can learn using the Encyclopedia Britannica. In fact if you stack 4 or 5 of them, you can build a pretty cool ramp, great for exploring the concepts of motion. Get a couple of toy cars and you're ready to roll! Measure the length of the track, how long it takes each car to reach the bottom, and you've got everything you need to calculate their speed.

Always chasing rainbows

This week during science the kids got A LOT of practice using a graduated cylinder. Each team had to follow very specific directions for adding and subtracting precise amounts of red, blue, and yellow water to produce a beautiful rainbow of colors. Afterwords we discussed possible sources of error including: spilling, not following directions, measuring incorrectly, and in this case, the starter blue water being too dilute, accounting for the strange greenish color all the groups got instead of purple.

Just for fun, estimate the volume of...

* a mouthful of water
* cup of apple juice
* a kiddush cup
* water used in your average bath

Then check yourself with a measuring cup. (This experiment was conceived during dinner one night when one of my kids INSISTED that the other one got more juice...)

Milk Mixer

What happens when you add a few drops of food coloring to water? What about milk? If you're in the mood for some psychedelic action, see what happens when you put some soap on the end of a toothpick and gently touch the surface of the milk.

We got off to a great start this week exploring these questions. First the kids had to learn how to measure liquid volumes using a dropper and a graduated cylinder. Graduated cylinder's kinda tough to say, but we counted, and it's still one less syllable than fancy schmancy measuring cup, so we all agreed to use the more scientific term. And of course, like all good scientists, we recorded our observations, results, and conclusions in our notebooks.