Investigation Lab
Learn how scientists set up investigations and use measurement tools to answer questions.
Learn
Scientists are like detectives. They ask questions about the world and then do investigations to find answers. An investigation is a careful way to test an idea.
Steps of an Investigation
- Ask a Question: What do you want to find out? Example: "Does a plant grow faster in sunlight or shade?"
- Make a Prediction: What do you think will happen? This is your best guess based on what you already know.
- Plan Your Test: Decide what tools you need and what steps you will follow.
- Gather Materials: Get your tools ready (rulers, thermometers, scales, etc.).
- Do the Investigation: Follow your plan and make careful measurements.
- Record Your Data: Write down your numbers and observations.
- Look at Your Results: What did the data show?
Fair Tests
A fair test means you only change one thing at a time. Everything else stays the same. This helps you know what really caused your results.
Example: If you test which paper towel absorbs the most water, you must use the same amount of water for each towel. Only the brand of paper towel changes.
Using Tools in Investigations
Different investigations need different tools:
- Ruler: Measure how tall something grows
- Thermometer: Measure temperature changes
- Scale/Balance: Measure how heavy something is
- Timer: Measure how long something takes
- Measuring cup: Measure liquids
Examples
Example 1: Plant Growth Investigation
Question: Do plants grow taller with more water?
Prediction: I think plants with more water will grow taller.
Plan:
- Get 3 same-size plants
- Give Plant A: 1 tablespoon of water daily
- Give Plant B: 2 tablespoons of water daily
- Give Plant C: 3 tablespoons of water daily
- Measure height with a ruler every 3 days
Fair Test Check: Same type of plant, same soil, same sunlight. Only the water amount changes.
Example 2: Ice Melting Investigation
Question: Does ice melt faster in warm water or cold water?
Prediction: Ice will melt faster in warm water.
Tools Needed:
- Thermometer (to check water temperature)
- Timer (to measure melting time)
- Same-size ice cubes
- Two cups with same amount of water
Fair Test Check: Same size ice cubes, same amount of water. Only the water temperature changes.
Example 3: Ball Bounce Investigation
Question: Which ball bounces the highest?
Tools Needed:
- Ruler or measuring tape (to measure bounce height)
- Different types of balls (tennis ball, basketball, rubber ball)
Fair Test Check: Drop all balls from the same height. Measure on the same surface.
Practice
Answer these questions about planning and doing investigations.
1. What is the first step in an investigation?
Show Answer
B) Ask a question - Every investigation starts with something you want to find out.
2. Maya wants to know if sugar dissolves faster in hot water or cold water. What tool should she use to check the water temperature?
Show Answer
C) Thermometer - A thermometer measures temperature.
3. What does "fair test" mean?
Show Answer
B) Only one thing changes - In a fair test, you keep everything the same except one thing.
4. Leo wants to test which paper airplane flies the farthest. What tool should he use to measure?
Show Answer
C) Ruler or measuring tape - He needs to measure distance.
5. Sara tests if a ball bounces higher on carpet or tile. She drops a tennis ball on carpet and a basketball on tile. Is this a fair test?
Show Answer
B) No - She changed two things: the type of ball AND the surface. She should use the same ball on both surfaces.
6. A prediction is:
Show Answer
B) Your best guess about what will happen - You make a prediction before you test.
7. Kim wants to know how long it takes for a seed to sprout. What tool should she use?
Show Answer
B) Timer or calendar - She needs to measure time (days until sprouting).
8. Put these steps in order: (1) Record data, (2) Ask a question, (3) Do the investigation, (4) Make a prediction
Show Answer
B) 2, 4, 3, 1 - First ask a question, then predict, then do the investigation, then record data.
9. Tom tests which type of soil helps plants grow tallest. He gives all plants the same water and sunlight. He only changes the type of soil. Is this a fair test?
Show Answer
A) Yes - He only changed one thing (the soil) and kept everything else the same.
10. Why do scientists write down their measurements?
Show Answer
B) So they can remember and compare data - Recording data helps you see patterns and share results.
Check Your Understanding
Challenge 1: Design an investigation to find out which brand of marker lasts longer. List: your question, your prediction, the tools you need, and how you will make it a fair test.
Show Sample Answer
Question: Which brand of marker lasts longer?
Prediction: I think Brand A will last longer because it feels heavier.
Tools: Paper, timer, ruler (to draw same-length lines)
Fair Test: Use same type of paper, draw same length lines, press with same pressure. Only change the marker brand.
Challenge 2: Explain why it would NOT be a fair test if you measured how fast ice melts, but used a big ice cube for one test and a small ice cube for another test.
Show Sample Answer
It would not be fair because you changed two things: what you are testing AND the size of the ice. A bigger ice cube takes longer to melt just because it is bigger. You would not know if the difference was because of what you were testing or because of the size.
Next Steps
- Practice identifying fair and unfair tests
- Try planning your own simple investigation at home
- Move on to the next lesson: Data and Graphs