Crosscutting Scientific Concepts

Cause and effect helps us answer two big science questions:

• What happened?
• Why did it happen?

In science, a cause is something that makes something happen.

An effect is what happens because of the cause.

A mechanism is the way the cause leads to the effect. It is the chain of steps in the middle.

When scientists study cause and effect, they do not just say, “These things happened together.” They ask, “Did one thing make the other thing happen?”

For example, if you flip a light switch and the light turns on, the cause is flipping the switch. The effect is the light turning on. The mechanism is that the switch lets electricity flow to the bulb.

Learning cause and effect helps us:

• understand how the world works,
• make good predictions,
• solve problems,
• and explain our ideas clearly.

How to find a cause and effect

1. Look at what changed.
2. Ask what happened next.
3. Think about how the first thing could make the next thing happen.
4. Check if the idea makes sense more than one time.

Sometimes one cause leads to one effect.

Sometimes one cause leads to many effects.

Sometimes many causes work together to make one effect.

Cause and effect in everyday science

If you water a plant, the plant may grow better. The water is a cause. Better growth is an effect. The mechanism is that the plant uses water to stay alive and make food.

If you leave an ice cube in the sun, it melts. The sun's warmth is the cause. The melting is the effect. The mechanism is that heat makes the ice change into water.

If you push a toy car, it rolls forward. The push is the cause. The rolling is the effect. The mechanism is that your push starts the car moving.

Cause is not just “at the same time”

Sometimes two things happen together, but one did not cause the other.

For example, children may wear coats on a cold day, and some trees may have no leaves. These happen at the same time in winter. But coats do not make leaves fall off trees.

Both things happen because the weather is cold. So we must be careful. Just because two things happen together does not mean one caused the other.

Ask:

• Did this thing happen before the effect?
• Is there a clear how or reason?
• Does it happen again in the same way?

Mechanisms are the “how” part

A mechanism is like a story with steps.

Here is a simple chain of events:

1. A girl kicks a ball.
2. The ball moves fast.
3. The ball hits a cup.
4. The cup falls over.

In this chain, the kick is the first cause. The cup falling is the final effect. The moving ball is part of the mechanism, or the middle steps.

Scientists often look for these steps because they help explain why something happened.

Worked Example 1: A simple cause and effect

Question: A student presses a button on a fan. The fan starts spinning. What is the cause? What is the effect?

Step 1: Find what happened first. The student pressed the button.

Step 2: Find what happened next. The fan started spinning.

Answer:

• Cause: pressing the button
• Effect: the fan spins

Mechanism: Pressing the button lets the fan turn on.

Worked Example 2: Finding the mechanism

Question: Rain falls on the playground. Later, puddles form. What is the cause, effect, and mechanism?

Step 1: What happened first? Rain fell.

Step 2: What happened next? Puddles formed.

Step 3: How did it happen? Water landed on the ground and collected in low spots.

Answer:

• Cause: rain falls
• Effect: puddles form
• Mechanism: rainwater gathers on the ground, especially in low places

Worked Example 3: Many causes, one effect

Question: A plant in a classroom looks healthy. It gets water, sunlight, and air. Why is the plant healthy?

Step 1: Look for possible causes. The plant gets water, sunlight, and air.

Step 2: Look at the effect. The plant looks healthy.

Step 3: Put the causes together. Plants need these things to live and grow.

Answer: This is an example of many causes making one effect.

• Causes: water, sunlight, and air
• Effect: a healthy plant

Mechanism: The plant uses these things to live and grow strong.

Worked Example 4: Not all things that happen together are cause and effect

Question: A rooster crows in the morning. Then the sun rises. Did the rooster make the sun rise?

Step 1: Did the crow happen before sunrise? Yes.

Step 2: Is there a clear way the crow could make the sun rise? No.

Step 3: What makes more sense? The rooster crows in the morning, and the sun rises because it is morning. They happen around the same time.

Answer: No. The rooster did not cause the sun to rise.

This teaches us to look for a real reason, not just two things happening together.

Tips for students

• Look for the event that happens first.
• Look for the event that happens next.
• Ask, “How did the first event lead to the next one?”
• Say the chain in order.
• Be careful: together does not always mean caused.

Try thinking like a scientist

When you see something happen, you can say:

• “I think the cause is ___.”
• “The effect is ___.”
• “The mechanism is ___.”

Here are some science questions you can ask:

• What changed?
• What happened after that?
• What steps happened in the middle?
• Could there be more than one cause?

More examples

• You drop a spoon. It falls to the floor.
  Cause: you let go of the spoon
  Effect: the spoon falls
• You blow on a pinwheel. It spins.
  Cause: moving air from your breath
  Effect: the pinwheel spins
• You put bread in a toaster. It becomes toast.
  Cause: heat in the toaster
  Effect: the bread changes into toast
• You forget to charge a tablet. It turns off.
  Cause: low battery
  Effect: the tablet turns off

Summary

Cause and effect helps us understand why things happen.

The cause is why something happens. The effect is what happens. The mechanism is the chain of steps that connects them.

Good scientists look for the real reason something happens. They do not just notice that two things happened at the same time. They ask, “What caused it?” and “How did it happen?”

Structure and Function means that the way something is built helps it do its job.

Structure is what something looks like and what it is made of.

Function is what something does.

In science, we ask an important question: How does the shape or material of something help it work?

We can look at plants, animals, and everyday objects. Many things have special parts that help them do special jobs.

For example, a bird has wings. The wings are part of the bird's structure. Their function is to help the bird fly.

A spoon is curved. That curved shape is its structure. Its function is to scoop food.

When we learn about structure and function, we learn that parts are made for purposes.

Main Idea 1: Shape helps with the job

The shape of something often helps it work well.

• A cup is open at the top so it can hold water.
• Scissors have sharp blades so they can cut.
• A fish has fins so it can swim through water.

If the shape changed, the job might be harder to do.

Imagine trying to drink from a flat plate instead of a cup. A plate does not have tall sides, so it cannot hold a drink well. Its structure does not match that function.

Main Idea 2: Materials matter too

The material something is made of also helps it do its job.

• A raincoat is made from material that keeps water out.
• A window is made of glass so light can come through.
• A wooden table is strong and hard, so it can hold things up.

If we made a raincoat from paper, it would not work well in the rain. Paper gets soggy and tears. The material would not fit the function.

Main Idea 3: Living things have body parts for jobs

Plants and animals have parts that help them live.

A plant has roots. Roots grow into the ground. Their function is to hold the plant in place and take in water.

A plant also has leaves. Leaves are often flat and broad. Their function is to catch sunlight.

Animals have body parts for different jobs too.

• A duck has webbed feet to help it swim.
• A rabbit has strong back legs to help it hop.
• A bear has sharp claws to dig and catch food.

Each body part has a structure that helps with a function.

Main Idea 4: We can compare structures and functions

Sometimes two things do the same job, but they have different structures.

For example, birds and airplanes both move through the air. But a bird has feathers and living wings, while an airplane has metal wings and an engine.

Sometimes two things look different because they do different jobs.

A boot and a sandal are both shoes. But a boot covers more of the foot and can protect your feet in mud or snow. A sandal is more open and helps keep feet cool. Different structures help with different functions.

How to think about Structure and Function

When you look at an object or a living thing, you can ask:

1. What parts does it have?
2. What shape are the parts?
3. What is it made of?
4. What job does each part do?
5. How do the shape and material help with the job?

These questions help scientists observe carefully.

Worked Example 1: Spoon

Let's think about a spoon.

• Structure: It has a curved bowl and a handle.
• Function: It scoops and carries food.

Why does it work? The curved part holds food, and the handle helps your hand hold the spoon.

If the spoon were flat like a ruler, it would not scoop soup well.

Worked Example 2: Bird Beak

Now think about a bird's beak.

• Structure: A beak can be short, long, pointed, or strong.
• Function: It helps the bird get food.

Why does it work? A pointed beak can help pick up small things. A strong beak can help crack hard food.

The shape of the beak helps the bird do its job.

Worked Example 3: Plant Roots

Let's look at roots on a plant.

• Structure: Roots grow down into the soil and spread out.
• Function: They hold the plant in place and take in water.

Why does it work? Because roots spread through the soil, they can help the plant stay standing and reach water underground.

If a plant had no roots, it would be much harder for it to stay in place and get water.

Worked Example 4: Umbrella

Now think about an umbrella.

• Structure: It has a wide top and waterproof material.
• Function: It keeps rain off your body.

Why does it work? The wide top covers you, and the material does not let rain pass through easily.

If the umbrella had holes in it, it would not do its job as well.

Things to remember

• Structure means how something is built.
• Function means what something does.
• Shape can help something do its job.
• Material can help something do its job.
• Plants, animals, and tools all have parts with special jobs.

Let's practice thinking

Here are some questions you can try asking yourself:

• Why does a fish have fins?
• Why does a cup have sides?
• Why does a cactus have a thick stem?
• Why are mittens made of warm, soft material?

When you answer, try to name the structure and the function.

Brief Summary

Structure and function are connected. The way something looks and what it is made of help it do its job.

We can see this in living things like roots, leaves, wings, and feet. We can also see it in objects like spoons, cups, umbrellas, and scissors.

When scientists study the world, they look at structures and ask how those parts help with functions. This helps us understand why things are built the way they are.

Measurement and Quantification means finding out how much of something there is.

Scientists measure things so they can observe carefully, compare fairly, and share what they learn with others.

In 1st grade, we can measure things like:

• Length — how long or how tall something is
• Mass — how heavy something feels
• Volume — how much space a liquid takes up
• Temperature — how hot or cold something is

When we measure, we use units. A unit is what we count with when we measure.

Sometimes we use non-standard units. These are simple units like paper clips, cubes, hands, or footsteps.

Sometimes we use standard units. These are units that many people use, like centimeters for length.

Why do scientists measure?

• To be careful and exact
• To compare two things
• To answer questions with evidence
• To tell others what they found

1. Measuring Length

Length tells how long, short, tall, or wide something is.

You can measure length with non-standard units, like linking cubes or paper clips.

To measure well:

1. Put the first unit at the start of the object.
2. Place each unit right next to the last one.
3. Do not leave gaps.
4. Do not overlap the units.
5. Count all the units.

You can also measure with a ruler using centimeters. Centimeters are standard units.

2. Measuring Mass

Mass tells how heavy something is.

In 1st grade, we often compare mass by using words like heavier and lighter.

A balance scale can help us compare two objects. If one side goes down, that object is heavier. If one side goes up, that object is lighter.

We can also use the same small objects, like cubes, to compare how heavy things are.

3. Measuring Volume

Volume tells how much liquid is in a cup, bottle, or jar.

We can measure volume by pouring liquid into the same-size cups or with a measuring container.

To compare volume fairly, we should use the same cup size each time.

We can use words like more, less, and equal.

4. Measuring Temperature

Temperature tells how hot or cold something is.

A thermometer helps measure temperature.

We may not need to read big numbers yet. We can still notice whether something is warmer or cooler.

Scientists measure temperature to learn about weather, water, and other things in nature.

Using the Same Unit Matters

If you measure one pencil with big blocks and another pencil with tiny buttons, your measurements will not be easy to compare.

To make a fair test, use the same kind of unit for both things.

That helps us collect precise data. Precise data means careful information.

Worked Example 1: Measuring Length with Cubes

Ella measures a crayon with cubes. She lines up 5 cubes with no gaps.

The crayon is 5 cubes long.

We can write it like this: \(5\) cubes.

Worked Example 2: Comparing Length

Ben measures two leaves.

• Leaf A = \(4\) paper clips long
• Leaf B = \(6\) paper clips long

Which leaf is longer?

Since \(6 > 4\), Leaf B is longer.

Worked Example 3: Comparing Mass

A toy car and a cotton ball are on a balance scale.

The toy car side goes down. The cotton ball side goes up.

This means the toy car is heavier and the cotton ball is lighter.

Worked Example 4: Comparing Volume

One jar fills 3 small cups of water. Another jar fills 5 small cups of water.

Which jar has more water?

Since \(5 > 3\), the jar that fills 5 cups has more water.

We can show it like this:

$$5 > 3$$

How Measurement Helps in Science

Imagine you want to know which plant in your classroom grew taller.

You can measure each plant with the same unit, like cubes or centimeters.

Then you can write down the data and compare.

That is what scientists do: they ask a question, measure carefully, and use the evidence to answer the question.

Tips for Good Measuring

• Start at the end of the object.
• Keep units lined up.
• Use the same unit each time.
• Count carefully.
• Check your work.

Let’s Remember

• Length tells how long or tall something is.
• Mass tells how heavy something is.
• Volume tells how much liquid there is.
• Temperature tells how hot or cold something is.
• We can use non-standard units like cubes and paper clips.
• We can also use standard units like centimeters.
• Using the same unit helps us compare fairly.

Summary

Measurement helps us describe the world with numbers and careful words.

When we measure length, mass, volume, and temperature, we learn more like scientists do.

If we use the same unit, line things up carefully, and count correctly, our measurements can help us answer questions with evidence.

Visualizing Data through Graphs and Charts

When scientists learn about the world, they collect data. Data means information we gather by looking, counting, measuring, or testing.

Sometimes a list of numbers is hard to understand. A graph or chart helps us see the data in a picture. Pictures can help us notice what has more, what has less, and what is the same.

In 1st Grade, we can use simple graphs and charts to share what we learned. This helps us explain our science work clearly.

Why do we use graphs and charts?

• They help us organize information.
• They help us compare groups.
• They help us see patterns.
• They help us tell others what we found out.

What kinds of graphs and charts can we use?

Here are some simple kinds of graphs and charts that young scientists can learn about.

• Tally chart: a way to count by making marks.
• Picture graph: a graph that uses pictures or symbols.
• Bar graph: a graph that uses bars to show how many.

1. Tally Charts

A tally chart helps us keep track while we count. Each mark stands for 1.

If we count 4 red flowers, we can write 4 tally marks: \(||||\).

Tally charts are helpful because we can count objects one at a time and record them right away.

Here is a simple tally chart for leaf colors:

Brown: \(|||\)

Green: \(|||||\)

Yellow: \(||\)

This tells us there are 3 brown leaves, 5 green leaves, and 2 yellow leaves.

2. Picture Graphs

A picture graph uses pictures to show data. Each picture stands for a number. In 1st Grade, it is easiest when each picture stands for 1 thing.

For example, if we asked, “Which pet do our classmates have?” we could make a picture graph.

Pets

Dog: 🐶 🐶 🐶

Cat: 🐱 🐱

Fish: 🐟

This picture graph shows that 3 students have dogs, 2 students have cats, and 1 student has a fish.

We can look at the graph and quickly see that dogs are the most and fish are the least.

3. Bar Graphs

A bar graph uses bars to show how many. The taller or longer bar means a bigger number.

A bar graph has:

• a title to tell what the graph is about
• labels to name the groups
• bars to show the numbers

Here is a simple bar graph idea about weather for one week:

Sunny: ████

Rainy: ██

Cloudy: ███

This means:

• Sunny happened 4 days.
• Rainy happened 2 days.
• Cloudy happened 3 days.

From the bar graph, we can see sunny happened the most.

How do we make a graph or chart?

1. Ask a question.
   Example: Which fruit do we like best?
2. Collect data.
   Count each answer.
3. Organize the data.
   Put the answers into groups.
4. Make the graph.
   Use pictures or bars to show the counts.
5. Look at the graph.
   Ask: What is most? What is least? Are any the same?

Words we use when reading graphs

• Most = the biggest number
• Least = the smallest number
• Same = equal numbers
• Data = information we collect
• Chart = a way to organize information
• Graph = a picture that shows information

Worked Example 1: Counting Birds

A class sees birds outside the window.

• 2 blue birds
• 4 red birds
• 1 yellow bird

We can put the data into a tally chart:

Blue: \(||\)

Red: \(||||\)

Yellow: \(|\)

Now let us read it.

• Red birds are the most.
• Yellow birds are the least.
• There are 2 blue birds.

Worked Example 2: Favorite Fruit Picture Graph

Students pick their favorite fruit.

• Apple = 3
• Banana = 2
• Grapes = 4

Picture graph:

Apple: 🍎 🍎 🍎

Banana: 🍌 🍌

Grapes: 🍇 🍇 🍇 🍇

Let us answer questions about the graph.

• Which fruit is the most? Grapes
• Which fruit is the least? Bananas
• How many students chose apples? 3

Worked Example 3: Plant Heights with a Bar Graph

A class measures how many blocks tall some plants are.

• Plant A = 2 blocks
• Plant B = 5 blocks
• Plant C = 3 blocks

Bar graph:

Plant A: ██

Plant B: █████

Plant C: ███

Now we read the graph.

• Plant B is the tallest.
• Plant A is the shortest.
• Plant C is taller than Plant A.

We can compare numbers too:

Plant B has \(5\) blocks. Plant A has \(2\) blocks.

Since \(5 > 2\), Plant B is taller.

Worked Example 4: Weather Data

A class watches the weather for 6 days.

• Sunny = 3 days
• Rainy = 1 day
• Cloudy = 2 days

We can show this with a chart first:

Sunny: \(|||\)

Rainy: \(|\)

Cloudy: \(||\)

Then we can make a bar graph:

Sunny: ███

Rainy: █

Cloudy: ██

What do we learn?

• Sunny happened the most.
• Rainy happened the least.
• Cloudy happened more than rainy.

How graphs help in science

In science, we often ask questions and collect data. Then we use graphs and charts to help us understand what we found.

For example, we might ask:

• Which seed grew the tallest?
• Which kind of weather happened most?
• Which object sank, and which object floated?

When we make a graph, we can see the answer more easily.

Tips for making a good graph

• Give your graph a title.
• Label each group clearly.
• Count carefully.
• Make sure each picture or bar matches the number.
• Check your work when you are done.

Things to look for when reading a graph

• What is the graph about?
• Which group has the most?
• Which group has the least?
• Are any groups the same?
• What does this tell us?

Let’s Practice Thinking

If a graph shows:

• Worms found in soil = 4
• Worms found under rocks = 2

We know more worms were found in soil than under rocks.

If a graph shows:

• White flowers = 3
• Pink flowers = 3

We know both groups are the same.

Summary

Graphs and charts help us turn data into pictures we can read. They help us count, compare, and understand information.

In 1st Grade science, tally charts, picture graphs, and bar graphs are great tools. They help young scientists share what they discover.

When you see a graph, remember to ask: What is most? What is least? What is the same?