【Science】Grade 3: Mastering How Plants Grow!
Hello, Grade 3 students! In this chapter, we’re going to learn about the "plants" all around us and how they grow big and strong.
"What happens after I plant a seed?" "In what order do they grow?" Let's work together to solve these mysteries!
Once you understand how plants grow, the flowers and grasses you see on your way to school every day will become much more interesting.
It might feel a little tricky at first, but don't worry. To start, try picturing familiar plants like sunflowers or touch-me-nots (balsam) as you read through this slowly.
1. It All Starts with a "Seed"
A plant’s life begins with a tiny seed. But not all seeds are the same! Depending on the plant, seeds can come in all sorts of different shapes and colors.
Observation Tips
Before you plant your seeds, take a close look at them:
・Shape: Is it round? Long and thin?
・Color: Is it black? Brown?
・Size: About how many millimeters is it?
💡 Fun Fact:
Sunflower seeds have striped patterns, but touch-me-not seeds look like tiny, brown, ball-like shapes. If you can guess which flower will bloom just by looking at the seed, you're a plant expert!
2. Sprouting: The Secret of "Cotyledons"
When you plant a seed and give it water, a sprout appears from the soil. The very first leaves that emerge are called "cotyledons." This is a very important word, so make sure to remember it!
Important Key Point!
・Cotyledon: The special leaf that comes out first from the seed.
・Cotyledons look different depending on the plant. Sunflowers have "rounded" ones, and touch-me-nots also have "round" ones, but if you look closely and compare them, you'll find differences.
❌ Common Mistake:
Many people think that when a sprout appears, it immediately has leaves shaped like beautiful flower petals. That’s a mistake! First, the baby-like cotyledons come out.
3. Growing Tall: Stems, Leaves, and Roots
After the cotyledons appear, new leaves will start to grow. These later leaves are different from the cotyledons and are called "true leaves."
The Order of Growth
1. Stem: Grows thicker and longer, reaching upward.
2. Leaves: The number of leaves increases, and they start to look like the typical leaves of that plant.
3. Roots: Grow wide and deep in the soil, supporting the plant and soaking up water.
Pro-tip:
Plants grow by spreading out their leaves to catch as much sunlight as possible. It looks like they are raising their arms in a "banzai" cheer to the sun!
4. Flowers Bloom and Fruits Form
Once the plant is big enough, buds will form and finally, flowers will bloom. What happens after the flowers bloom?
Passing the Torch of Life
After the flower fades, fruit (or seed pods) will form. And inside that fruit, there are new "seeds" packed away.
・Sunflower: A large flower head packed with many seeds.
・Touch-me-not (Balsam): When the pod gets ripe, it pops open to launch the seeds far away.
💡 Fun Fact:
If you touch a ripe touch-me-not seed pod, it might pop open with surprising force! This is because the plant wants its "children" (seeds) to grow in a wide, open space far away. Isn't that a clever plant trick?
5. Summary: The Life Cycle of a Plant
Let's review the order in which a plant grows one more time.
【Seed】 → 【Sprout (Cotyledons) appears】 → 【Stems and leaves grow】 → 【Flowers bloom】 → 【Fruit forms (Seeds are made)】
This is how plants pass their life from one seed to the next. We call this a "life cycle."
Key Summary Points
1. The first leaves to appear are called "cotyledons."
2. As they grow, the stems, leaves, and roots become stronger.
3. After the flowers, fruit forms, containing the seeds.
4. Plants pass on life from "seed to seed!"
It might feel like there's a lot to remember at first, but you'll pick it up naturally by observing plants every day. Treasure your discoveries, like when you notice, "There's a leaf here that wasn't here yesterday!" I'm rooting for you!