Science Buddies

Do you feel like you've seen this before? 

It's because this website is the home of the Flour Daniel Engineering Challenge, too. However, since I'm not sure if a lot of people went beyond looking at the website for Flour Daniel Engineering Challenge info, I decided to highlight the website  on its own.

Science Buddies Website

I like this STEM website for its breadth of science projects it offers.There's an endless supply of Science projects.

Just look at these lists.

Once, you select a project by topic of study, it will give you a more detailed list of projects with short descriptions.

Once you choose a project, you can access:

• Project Summary
• Background
• Materials
• Procedure

This website also encourages you to make the project your own. Be creative and experiment. However, there are quite a few projects where you need to figure out the details of the project. Which is a good thing for some and not so much to the others.

But at the end of the day, this is a great website for all things STEM. 

I hope you look around and try some projects.

Have a great day!

Are you a Conductor?

No. I'm not talking about a train conductor. I'm talking about a conductor of electricity, and this is the experiment I'm going to do today. Let's get started.

List of Supplies:

• AA battery
• Strip of foil (thickness doesn't matter)
• Clothespins (wooden or plastic doesn't matter)
• Multimeter*
• Lemon
• 1.5V light bulb
• Leaf
• Yarn
• Paper Towel
• Anything you have around the house, you can use to test the conductivity of electricity.

Fold a strip of foil and fold it a couple of times (this one in the picture is tri-folded) then tape the strips of foil to the both ends.

Wrap the strips of foil around the ends of the multi-meter probes and clip them in place with a couple of clothespins. AA battery should carry 1.5V right out of the package, and this one is close at 1.45V.

Just for fun, we clipped the strips of foil on the metal ends of the 1.5V light bulb housing. But if you can't find these easily, you can just wrap the foil around the bottom of the bulb, and clip them in place, it'll work just fine.

Another view, just for a better look.

I was initially trying to use the light bulb test for conductivity, but some voltages were so low that it wouldn't light up the bulb. So, I chose to use multi-meter to read the low voltages.

Clip one end of the probe to a foil strip then clip the other end of the foil strip from the other side of the battery to the whatever material you're going to test for conductivity. 

As the multi-meter shows, a piece of yarn is NOT conductive.

As the multi-meter shows, a leaf is low in conductivity. No wonder, a leaf couldn't light up a bulb. The bulb needed 1.5V and the leaf only carried 0.38V. That's a huge gap.

As the multi-meter shows, a piece of paper towel is NOT conductive.

Now, look at this! 

The multi-meter shows that a piece of lemon INCREASED the voltage 

from 1.45V to 1.81V.

As the multi-meter shows, the plastic parts of the clothespin are NOT conductive.

Notes on multimeter:

You can purchase one from Harbor Freight for $5.99, but if you have one of their coupons, you can get it for Free. If you don't have a Harbor Freight nearby, you can purchase one from Home Depot for less than $10.00 (I've seen it as low as $6.99).

Science Notes:

• As you test the materials you find around the house, you will notice that some of the materials will let electricity pass through them, and the multi-meter will show that on its screen or the light bulb will turn on.
• The materials that let electricity pass through them are called conductors.
• The materials that won't let electricity pass through them are called insulators (all the materials that read 0.00 on the multi-meter.
• Living things are good conductors as well as wire, metal and water.
• Non-living things such as plastic, rubber and paper are good insulators.

Question:

Why should you not swim or play outside during a thunderstorm?

Answer:

Lightning is an awesome and powerful form of natural electricity. And you are a living thing. That means you are a good conductor, and lightning could kill you.

Well, I hope you had fun and learned something new.

Have a great day.

Car Engine Cam (Mechanisms) - Page 146, Build #186

My goal is to engage elementary school children to be curious about the world around them, and I think this simple cam & follower car engine is a great example. 

This is the one I wanted to build for over a month, but I didn't have the parts. When I ordered the cam parts (LEGO apparently calls the part comb wheels, and I don't get the connection), it took THREE weeks to get to northern California.

This is what I'm building today.

Parts I'm going to use today:

 

The hardest part of building this cam was to put this long piece with a flat end (right hand side) through the red technic piece (left hand side)  AFTER assembled the legs already.

I really enjoyed making this, and it's really fun to watch. 

I hope you make one today. Have a great day!

Ranger's Apprentice, The Ruins of Gorlan by John Flanagan

I love this book, and I first read this book in 2010. And I've re-read this book a couple of times more, since.

My son discovered this book at his elementary school book fair, and since then our whole family (my husband included) is a fan of this series.

Will No-Name is a fifteen-year-old orphan who is raised with other wards, including Alyss, Jenny and Horace, at Castle Redmont under Baron Arald’s care. Will believes that his father was a mighty warrior who died in an important battle, but Horace ridicule and harass Will at every opportunity. 

Growing up in Castle Redmont, Will dreams of attending Battleschool and becoming a knight of renown, just like his father. But in Will’s world, he doesn’t get to choose. He must be chosen by one of the masters at Castle Redmont on the Choosing Day, and the Battle Master doesn’t choose him. The Battle Master thinks Will is too small. Instead, he is chosen by Halt, the Ranger, as his apprentice.

Much to Will's chagrin, Horace is chosen by the Battle Master for the Battleschool, but Horace's life is made miserable by older boys in the Battleschool. And on the outside of the castle walls, a war is brewing. The exiled Morgarath, Lord of the Mountains of Rain and Night, is getting ready to attack the kingdom of Araluen. 

This time, Morgarath vows, he will be triumphant.

This is a great start of a new series. The author does a great job of creating characters that are real and sympathetic. I want to know everything there is to know about Will and Halt. Every time, I hope this looming war won't take too much from the people of Redmont.

I read the whole series, and the next series by the same author called Brother Band Chronicles (Stories of Viking world).

Being female, I wish there were more stories of Jenny and Alyss, rather than Will and Horace.... But I guess I have to remember that this is the Ranger's Apprentice, not Cook's Apprentice or Diplomat's Apprentice. 

I would recommend this book to advanced readers of 3rd graders or older (there's nothing graphic or bad in there - a kiss and a couple of battle scenes).

Though I loved both Harry Potter Series and Eragon Series, I think the Ranger's Apprentice Series is a better one. The world is more real. The dangers are more urgent. And it's up to a group of fifteen-year-olds to save the world.

PS - Rangers in this series are like the Army Rangers of United States, special forces soldiers. The Rangers try to fight and win battles before battles reach the people.

Not-So Shocking Chemistry

Today, we're going to find a way to shock (maybe) your friends.

What we're making today - a wet cell battery. 
Wet cells were used before batteries as we know it now were invented.

List of Supplies:

• Lemon juice (fresh lemons or a bottle of lemon juice OK)
• Paper towels (cut into small pieces. Not too much bigger than the coins)
• Bowls (one small and one big enough to hold the juicer)
• Coins (equal number of nickels and pennies). I used 15 coins each.
• Multimeter*
• Lemon/citrus juicer (optional)

Cut the lemon in half and squeeze the juice into a small bowl.

Soak the pieces of paper towel in the lemon juice.

Begin to stack coins, starting with a penny and alternate between nickels and pennies.

Measure the voltage between the coins (2 sets of pennies and nickels). 

The multimeter reads 190 micro volts. 

Try to measure the voltage readings. 4, 8, 12 and 15 sets of coins 

or 3, 6, 9, 12 and 15 sets of coins.

This is one of the reading for 15 sets of pennies and nickels.

My voltage readings were as follows:

• 4 sets of coins, 190 micro volts
• 8 sets of coins, 206 micro volts
• 12 sets of coins, 303 micro volts
• 15 sets of coins, 530 micro volts

I noticed that the longer I hold the leads to my coin battery, the higher the voltage readings. I had 12 set of coins read higher than 530 micro volts when I held the leads against the coins for over 45 seconds. The above readings were what I got within 10 seconds of holding the leads to the coin battery.

Theoretically, when you touch the ends of your coin stack with your fingers, you should feel a mild shock, but I didn't feel anything. Maybe I did something differently? Maybe you'll feel something. I don't know.

Science Notes:

•  The two types of coins have different electrical charges in their atoms.

1. Nickel (anode) is electron rich, which means it's negatively charged.
2. Copper (cathode) is electron poor, which means it's positively charged. 
3. The electrons will flow from Nickel to Copper coins and create an electric circuit.

• Lemon juice, which is a weak acid, conducts an electric current between the two different coins.
• By stacking coins on top of one another, we’re increasing the electric voltage of our wet cell battery. So, this explains why when we have 15 sets of coins should give us the highest voltage reading.

Notes on multimeter:

You can purchase one from Harbor Freight for $5.99, but if you have one of their coupons, you can get it for Free. If you don't have a Harbor Freight nearby, you can purchase one from Home Depot for less than $10.00 (I've seen it as low as $6.99).

Mess factor:

It really wasn't too messy. Basically, confined to a tray and a bigger bowl.

I hope you have a great day.

Stock Market Game

I love this competition. This one is all about Math, but what a great and fun competition it is!

So, the premise of the Stock Market Game is that each team gets $100,000 to invest for the competition period. There are three awarded competition periods - 8 weeks in the fall, 8 weeks in the spring, and a year-long competition that runs from Oct to Apr. Teams that place 1st, 2nd and 3rd receive awards from the Stock Market Game organization.

The United States is divided into regions, and top 3 regional winners are invited to an award ceremony. In northern California, the award ceremony is held at the Bank of America building in San Francisco.

The Stock Market Game Website

The 1st page of the website. This website offers a lot of resources for the teachers to use in classrooms. You can also request a professional to come out to your classroom to do a presentation to your students. I have several kids participating in this program as an after-school activity. So, that's an option for you to consider as well. The regional manager I interact with is great. She is responsive and prompt. 

This is one of my team's rankings in the year-long competition. This team was ranked as high as 3rd in Dec/early Jan but fell in the rankings since. The key to this competition is to encourage your students to trust their research and NOT to be impulsive when stocks are sliding. And not to trade too often. One teacher I know limits trades to 3 trades in the 8-week competitions.

This shows how much of a team's money is invested and how much  is held in cash.

This screen shows the top holdings of all the teams that are participating in the competition. Yes. You do see a lot of usual suspects, but I also encourage my student to dig around a little and find at least three stocks on their own (these would be stocks you wouldn't normally see on the top holdings list).

Other programs the Stock Market Game offers.

Why do I like this so much? I find that this website makes Math come alive for many of the students. Before we start, I have the students do research stocks and ask them to compare the stocks they like (we look at short-term, 2 months, and long-term, 7 months performance) and tell them to decide based on their research and calculations.

It's amazing what kind of responses I get. One time, I saw a stock symbol I've never seen before and asked a student about it. And she said, I know my money could do better in big name stocks, but this pharmaceutical company has a kidney cancer drug coming up for FDA approval in next February (meaning right now), and it’s going to take off. According to my research, it is highly likely that the drug is going to get approved because it's already doing well in another cancer study. 

Isn't this an amazing explanation? I didn't expect that from a 6th grader. 

And it's also fun to say, "Don't you want to know how your investment is doing?" when a student asks, "Why do I have to learn long division?"

I guess I like this program, because it's SO much more than just about stocks.

And the best part? It's not too late to participate in the spring or the year-long competition. So, why don't you check it out? 

Have a great day.

Attaining Invisibility!

Did you ever wish you had Harry Potter's Invisibility cloak? 

I certainly did when I read the books and watched the movies. 

So, do you think you can be invisible? 

It all depends....

Our eyes...

First, let's talk about how we see (how things become visible to us).

Some facts about how we see:

• Light rays are reflected from a surface in straight lines. 
• When light rays hit a smooth surface, the light rays are reflected back at you.
• When those light rays enter our eyes and hit our retinas, an image is formed (upside down)
• When light rays hit an uneven surface, the light rays are scattered. The reflected light bounces off in all directions, unable to form a coherent image.

Do you see the light colored blob in the bottom of her eye? That's me, reflected in her eye. Isn't it amazing?

So, how do we achieve invisibility in Real Life? 

How about a stealth fighter plane/helicopter/ship?

• As the radar antenna turns, it emits extremely short bursts of radio waves, called pulses. The pulses move through the atmosphere almost at the speed of light. By recording the direction in which the antenna was pointed, the direction of the target is known. The better the target is at reflecting radio waves, the better it will be able to attain invisibility.
• Stealth technology cannot make the aircraft invisible to enemy or friendly radar. All it can do is to reduce the detection range of an aircraft. This is similar to the camouflage tactics used by soldiers in jungle warfare. Unless the soldier comes near you, you can't see him.
• Reduce radar cross section
• Change vehicle shape to reflect radio waves in all directions
• Use new technology to absorb/trap radar waves
• Use of non-metallic airframe

A simple experiment on invisibility

For this experiment, you'll need large piece of foil (large enough to see your face in). 

• Be careful to cut/tear that piece of foil without crinkling it at all.
• Smooth it out (don't touch it too much) and look at yourself in the foil. Sure. It's not like a mirror, but you should be able to make out your facial features.

• Now, crumple that sheet of foil into a fist-sized ball.

• Then, open it up and smooth it out as well as you can.

Now, can you see yourself in the foil? You can't. So, why do you think you can't see yourself at all in the same sheet of foil?

When the foil is scrunchy and rough, the reflected light bounces off in all directions. And because these reflected rays are going off in all directions, your face does not form in the way it did before.

This is a very simple experiment, but there's a lot to learn from it. For deeper learning, search for pictures of stealth planes, stealth helicopters, stealth ships, etc. There are a lot of angles on the vehicles. Not smooth like the traditional vehicles.

Have fun and enjoy the day!