Science Fenns K-5Grades K to 5
A child drawing a line graph on grid paper next to a ruler, a thermometer in a cup and a stack of notes.

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Data, Patterns and Error

Graphs that tell the truth and errors that hide.

Lesson 4 of 41

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Before we start

Today’s story

Data, Patterns and Error

You can tell a lot from a table of numbers, but a graph shows it faster. A line that climbs says something is growing. A line that drops says it is shrinking.

Every measurement can be a little off. A ruler slips. A reading is rounded. That is called error. Good scientists look for where error might hide and try to shrink it.

Today we build a graph, find a pattern, and hunt for error. We start with a table. Here are the steps.

See it

Five steps. Every time.

    Hands on

    Cooling Cup Graph

    30 minutes · Do this with a grown-up nearby

    You need

    • Cup of warm tap water
    • Thermometer
    • Clock or timer
    • Graph paper
    • Pencil

    Do this

    1. Pour warm tap water into a cup. Not hot.
    2. Read the temperature and write it down.
    3. Read the temperature every two minutes for twenty minutes.
    4. Make a table of time and temperature.
    5. Plot each point on graph paper and connect them.
    6. Find the total change in temperature.
    Write or draw: A table and a line graph of time on the bottom and temperature up the side.

    Watch for: Does the water cool at the same speed all the time? Where could your reading be off?

    Safety: Use warm tap water only, never hot water from a stove.

    Same every time

    Three rules

    Rule 1Label your graph

    Titles and units tell the reader what the numbers mean.

    Rule 2Look for odd points

    A point far from the rest might be an error. Check it.

    Rule 3Repeat to shrink error

    More trials reduce the effect of one bad reading.

    Grandpa Fenn’s notebook

    Say it like a scientist

    pattern
    Something that repeats or changes in a regular way.
    error
    The difference between a measurement and the true value.
    average
    The sum of numbers divided by how many there are.
    graph
    A picture that shows how numbers relate.

    Poppy’s quiz

    Six questions

    Tap an answer. Green means right. You will see why.

    Talk about it

    Say it out loud

    • How do you know a pattern in data is real?
    • Where at home could a graph help, like tracking rain or a pet's weight?
    Did you know

    Scientists often take the same measurement many times, because small errors tend to average out.

    Someone who does this

    A weather forecaster reads patterns in data to predict the next few days.

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