Science Fair for KIDS @NUE 20250731

🧪Activity 1: How Plants Transport Water

If we put a flower into water with food coloring,
what do you think will happen?

How does the plant move the water upward?

Yes! Plants must have tiny tubes inside that help carry the water up.
So the food coloring will travel along these tubes and reach the flower petals.
That’s why the flower may turn red—or blue—depending on the color we use.
(Note: Different kinds of flowers might show the color in different places, not always in the veins or vascular bundles.)

Now, look at the chopsticks we're using.
What are they made of?
Right, they’re made from wood or bamboo—plant materials.

So, what do you think will happen if we try to blow bubbles using a chopstick?
Let’s try it and see!

After you try, let’s compare:
How are these bubbles different from the ones we blow with straws?

Exactly! The chopstick hole is much smaller, so the bubbles are smaller too.

This experiment helps us prove that even in chopsticks, there are tiny channels inside—just like in plants!

Now, let’s use our smartphone microscope to observe the structures plants use to transport water.

Look closely — the plants you’re observing can be divided into two groups:

• Group 1: Bamboo and lily
  These are called monocot plants, and their vascular bundles are scattered throughout the stem.

• Group 2: Wood blocks and chrysanthemum
  These are dicot plants, and their vascular bundles are arranged in a ring.

You can try comparing them and see if you notice the difference!

Alright! That’s the end of our first activity: Plant Water Transport.

⚓️Activity 2: Pressure and Buoyancy

Now, we’re going to use this little soy sauce fish bottle to make a mini submarine — also called a Cartesian diver!

First, fill the little fish with water.
You can try any way you like, but in the end, only the tail of the fish should float above the water.

Next, place the fish into a plastic bottle filled with water.
We’re also going to make a small anchor inside the bottle —
so that when the fish sinks, it can hook onto the anchor.

After you finish, try squeezing the bottle to make the fish dive down.
Try to hook the anchor and keep it underwater.

Once your fish is successfully fixed under the water, come tell the teacher!

What just happened? Why did the little fish sink when we squeezed the bottle?

Let’s do another experiment to help us understand this.

Here we have a closed syringe with a marshmallow inside.
If I push the plunger down, what do you think will happen to the marshmallow?
Will it get squished sideways?
Up and down?
Or will it shrink overall?

What do you think?

Now, try it yourself.
Take a syringe and one marshmallow and give it a try.

Alright — we can see that the marshmallow really gets smaller!
This is very similar to what happens in the bottle.
When we squeeze the bottle, the air inside the fish also gets smaller, and some water goes into the fish.
So the overall buoyancy decreases, and the fish sinks.

But when we let go of the bottle, everything goes back to normal —
the fish floats back up!

This is the result of how pressure and buoyancy work together.

Activity 3: Light and Color

Look at the light in my hand.
What color is it?

Yes, it looks like it's flashing in many colors very quickly —
but when they all mix together, what color do you think it becomes?

That’s right.
Actually, this light only uses three colors: red, blue, and green.
You see white because your brain combines these lights into white.
But when I move it quickly, the lights get separated for a moment, and you can see the individual colors.

We can see colors because we see light.
So when we shine red light on white paper, we don’t see white — we see red.

Now, let’s try shining white light through a green transparent cup.
What color do you see? Yes, only green.

What if I stack a red transparent cup on top?
What if I add even more cups?

What changes can you observe?

Because of light, we are able to see the world around us!

Advanced Challenge (for older students)

You can use this grid paper and the transparent green board to draw the position of a mirror image.

First, draw a straight line on the paper.
Place the transparent board along this line.
Then, write the letter F in front of the board.

Look through the board and observe the mirror image of F.
Trace the shape of the mirrored F on the paper.

Now, measure the distance between the original F and the board,
and also the distance between the mirrored F and the board.

This will help you understand the principle of mirror images.

発展チャレンジ（年上の生徒向け）

この方眼紙と透明な緑のボードを使って、鏡像の位置を描いてみましょう。

まず、紙に一本の直線を描いてください。
その線の上に、緑の透明ボードを置きます。
次に、ボードの手前にFという文字を書いてください。

ボードを通してFの鏡像を観察し、
その形を紙に写し取ってください。

元のFと鏡像のFが、ボードからそれぞれどれくらいの距離にあるかを測ってみましょう。

鏡像のしくみを理解することができます。

Color Separation (Chromatography)

We just learned about light — now let’s explore color!

How are our color markers made?
Do you think a gray marker is made of just gray ink, or is it a mix of other colors?
What about green?

In this experiment, we’ll find out whether each marker color is made of a single color or a mixture of several colors.

First, cut a piece of coffee filter paper into a strip.
Then, using different markers, place small dots of color near the bottom of the strip — like this.
Choose at least three different colors, and be sure to include one oil-based marker.

Next, use tape to attach the top of the filter paper to a chopstick.

Fill a cup with just a little bit of water — about 0.5 cm —
so the bottom of the filter paper touches the water.

Now, what do you think will happen?

Let’s wait and observe quietly.

After about five minutes,
what do you notice?
What interesting things can you see?

Now we’re going to do a chemistry experiment, and for this one, safety is very important.
Please follow the teacher’s instructions carefully.

We can easily buy baking soda and citric acid — these are great helpers for cleaning at home.
For example, look at this coffee cup the teacher has — it’s super dirty!
But with just baking soda, we can easily clean off the coffee and tea stains.

Now, what happens when we mix baking soda and citric acid together?
Actually... not much.
But if we add water, something interesting happens!

It will start to produce a lot of bubbles.
Even though it looks like nothing is inside, it’s actually filled with a lot of invisible gas.

We can even use this gas to do some magic-like tricks — like putting out a fire without touching it!

In a moment, I’ll show you a demonstration using a candle and fire,
but please do not try this part by yourself.
Make sure an adult is with you — that’s the safest way.

Now, let’s watch the amazing effect.
We can understand that this chemical reaction produces a kind of gas that is heavier than air, which helps us put out the flame.

Here’s how we’ll do the experiment:

1. Put baking soda into a medium ziplock bag.

2. Put citric acid and water into a small ziplock bag.

3. Place the small bag inside the medium bag, but don’t seal it yet.

4. Tape the medium bag shut (except for sealing it completely).

5. Then put the whole thing into a large ziplock bag and seal that bag tightly.

6. Show it to the teacher for safety check.

Once you’re ready, press and break the small bag inside — and observe the reaction!

Important:
If you try this experiment by yourself, it could be dangerous —
the liquid might splash into your eyes.
So always be careful and stay safe!