Skip to main content
Sign in Create a free account
Varsity Tutors
Sign in
Back to lessons

2nd Grade Science (Next Generation Science Standards) • K-2 Engineering Design

Which Design Works Better?

Let's find out how to test two ideas and compare them to see which one solves a problem best!

Explore the lesson 6 min read
A microscope with leaf and experiment flask for elementary science discovery
Inside this lesson 9 sections 4 questions 5 figures

Section 1

What's Happening?

ℹ
🔍 Look at This!

You both try your ideas. After 5 minutes in the rain, you check. Which cover kept the toy drier?

Design APaper PlateA little wet 💧Design BPlastic BagDry! ✨VS
Two designs being tested in the rain: a paper plate cover and a plastic bag cover over a toy
ℹ
💭 Thinking Questions
  • Which cover do you think will work better? Why?
  • How could you tell which one won?

Section 2

Big Ideas

When we have a problem, we can think of more than one way to fix it. We call each way a design (that means a plan or idea for how to solve the problem).

But how do we know which design works best? We test each one! Then we collect the results — that means we write down or draw what happened.

1

Test Both Designs

To be fair, we test both ideas the same way. We give them the same problem and see what happens.
2

Collect the Results

We look carefully at what happened in each test. We can draw, write, or use a chart to show what we found.

Section 3

Let's Try It!

ℹ
🔬 Let's Try It!

We will build two different walls at the bottom of the ramp. Then we will roll a ball down and see which wall stops it better!

What You Need:

A flat board (ramp), a small ball, blocks, and cardboard pieces.

Worked example

  1. 1

    Step 1

    Make Design A: a wall of blocks at the bottom of the ramp.
  2. 2

    Step 2

    Roll the ball down the ramp. Watch what happens. Write it down!
  3. 3

    Step 3

    Now make Design B: a wall of folded cardboard at the bottom.
  4. 4

    Step 4

    Roll the ball again. Watch what happens. Write it down!
Our Test SetupDesign A: Block WallRampballblocksBall stopped ✅Design B: Cardboard WallRampballcardboardBall rolled past! ❌We write down what happened for each design.That is collecting results!
Diagram showing two ramp designs: Design A with a block wall and Design B with a cardboard wall

After you try both designs, you have results! Results tell you what happened in each test. Now you can compare them side by side.

Section 4

What We Found

When we tried our test, we found out something important! We can use a chart to show our results. A chart makes it easy to compare.

What We TestedDesign A (Blocks)Design B (Cardboard)
Did the wall stay up?✅ Yes!❌ It fell over
Did the ball stop?✅ Yes!❌ It rolled past
Was it easy to build?It took a little timeVery fast

Look at the chart. Design A worked better at stopping the ball. But Design B was faster to build. The results help us see what is good and what is not so good about each design.

This is why we collect results — so we can look at the facts and make a smart choice!

Comparing Our ResultsDesign A: Blocks✓Wall stayed up✓Ball stopped~Took some time⭐⭐⭐Design B: Cardboard✗Wall fell over✗Ball rolled past✓Very fast to make⭐
Results chart showing a side-by-side comparison of two designs with checkmarks and X marks

Section 5

Spot the Pattern

Do you see a pattern? When we compare two things, we learn more than if we only look at one thing. This is called comparing. Scientists and engineers compare things all the time!

Let's see some examples:

What We CompareWhy We Compare
🥾 Two pairs of rain bootsTo see which ones keep feet drier
🌱 Two ways to plant seedsTo see which way helps plants grow taller
🏗️ Two toy bridgesTo see which one holds more weight

See the pattern? When we test two things and collect results, we can figure out what works best. This pattern works for rain boots, plants, bridges, and anything else you can test!

Section 6

Real World

People use testing and comparing every day to solve real problems!

1

Building Better Houses

Builders test different roof shapes to see which ones keep rain out the best. They collect results and pick the best one!
2

Making Backpacks

Backpack makers test different straps. They see which straps are most comfy and don't break. They compare and choose the best.

Engineers are people who solve problems by designing and building things. They always test more than one idea. Then they look at the results to find the best solution.

You can be an engineer too! Next time you have a problem, think of two ideas. Test them both. Collect your results. Then pick the winner!

Section 7

Key Vocabulary

ℹ
📖 Key Vocabulary
  • Design — A plan or idea for how to solve a problem.
  • Test — To try something out to see what happens.
  • Results — What happened after a test. The information we collected.
  • Compare — To look at two or more things side by side to see how they are the same or different.
  • Engineer — A person who solves problems by designing and building things.

Section 8

Practice: Show What You Know!

Question 1: Applying What You Learned

Jada and Sam want to keep ice cubes from melting. They make two containers — one wrapped in cotton and one wrapped in foil. Why should they test both containers and write down what happens?
  • A. So they can compare the results and see which design works better
  • B. So the test takes longer and fills more time in class
  • C. Because using both materials together will make the best container
  • D. So they can use the results from one design to skip testing the other
Show answer
The answer is A. When you test both designs and collect results from each one, you can compare them to see which design solves the problem better. You cannot skip testing one design or mix them together — each design needs its own test and its own results.

Question 2: Collecting Data

Leo's class built two different toy boats to see which one could hold more pennies before sinking. What result should they collect during the test?
  • A. The size of each boat
  • B. The number of pennies each boat held before it sank
  • C. The name of the person who built the boat
  • D. How long it took to build each boat
Show answer
The answer is B. The problem is about which boat holds more pennies. So the result they need to collect is the number of pennies each boat held. The size of the boat is a design detail, not a test result. The builder's name and the build time don't tell you which boat worked better.

Question 3: Thinking Deeper

Maya tested two fan designs to see which one moved air farther. Fan A moved a piece of tissue 4 steps away. Fan B moved a piece of tissue 7 steps away. What should Maya do with these results?
  • A. Throw away the results and guess which fan is better
  • B. Compare the two numbers to decide which fan moved air farther
  • C. Only keep the results from Fan B because it did better
  • D. Add the two numbers together to get one score for both fans
Show answer
The answer is B. Maya should compare the results from both fan designs. Fan B moved the tissue 7 steps, which is more than Fan A's 4 steps. By comparing the numbers side by side, she can see which design solved the problem better. You should never throw away results or only keep one — you need results from both designs to make a fair comparison.

Question 4: Real-World Connection

Two groups each built a different ramp to help a ball roll into a cup. Group 1's ball went into the cup 2 out of 5 times. Group 2's ball went into the cup 4 out of 5 times. Which is the best way to record these results?
  • A. Draw a picture of only the ramp that worked the most times
  • B. Tell a friend about it but do not write anything down
  • C. Write down the number of times the ball went in for both ramps in a chart
  • D. Only write down whether the groups had fun building their ramps
Show answer
The answer is C. The best way to collect and record results is to write down the numbers for both designs in a chart. This way you can clearly compare how each ramp performed. Recording only one ramp, not writing anything down, or writing about fun instead of results would not help you figure out which design works better.

Section 9

What's Next?

ℹ
🔮 What's Next?

Varsity Tutors • 2nd Grade Science (NGSS) • Which Design Works Better?