Unit 1: Measurement and the Scientific Method

“You can observe a lot just by watching.”

-Yogi Berra

The Scientific Method…

• What is the first step in the Scientific Method?

• 1. Make observations

• 2. Explain observations with a hypothesis

• 3. Collect data to test hypothesis

• 4. Evaluate data –what does it tell you about your hypothesis?

What is an observation?

• An observation is the gathering of information by using our five senses:– Sight

– Smell

– Hearing

– Taste

– Touch

• There are two types of observations:– Qualitative

– Quantitative

Qualitative Observations

• Qualitative observations describe what we observe.

• “Qualitative” = quality (descriptive)

• These observations use adjectives to describe something.

• Example: The flower has white petals.

• Example: Mr. Dallai is a tall dude.

Quantitative Observations• Quantitative observations measure what

we observe.• “Quantitative” = quantity (numerical)• These observations use numbers to

measure something in a quantitative way.

• Example: The flower has seven petals.• Example: Mrs. Nichols has two eyes.

Which is better?• Both types of observations are valuable in

science. In an experiment, though, quantitative observations can be precisely and objectively (without bias) compared.

Qualitative: The road is long. (describes)

Quantitative: The road is 5.2 km long. (measures)

• Some things are easier to quantify than others. Scientists use innovative ways of turning qualitative into quantitative…usually by creating a scale.

Which is better?

• For example, someone might say that a dead fish is smelly.

• It is hard to know just how smelly the fish is, though….

• To make this quantitative, the scientist could ask the person to rate the “smelliness” on a scale of 1-5.

• This would then allow you to compare how smelly the fish is!

Inferences

• An inference is a possible explanation for an observation you have made.

• Inferences are based on your past experiences and prior knowledge.

• Inferences are often changed when new observations are made.

• Again, observations are information we gather directly through our five senses….inferences help explain those observations!

Here are some examples!• Observation: The grass on the school’s front

lawn is wet.• Possible inferences:

– It rained.– The sprinkler was on.– There is dew on the grass from the morning.– A passing dog peed on the grass!

• All of these inferences could possibly explain why the grass is wet. They are all based on prior experiences. We have all seen rain, sprinklers, morning dew, and dogs going to the bathroom.

Another example…

• Observation: The school fire alarm is going off.

• Possible inferences:– The school is on fire.– We are having a fire drill.– A student pulled the fire alarm.

• Again, these are all logical explanations for why the fire alarm is going off.

Tracks like these are common in parts of New

England and in the southwestern United

States.

What do you OBSERVE?

What can you INFER?

Now what do

you think?

Infer what happened based on your observations.

Group Practice• Make some observations and inferences

about the following picture.

Individual Practice• In your notebook, please write down 2 observations and 2

inferences about the following picture.

Measurement

• Why is measurement important?

• Sometimes our senses can be fooled when making observations….

How many legs does the elephant have?

What do you see?

What do you see?

Hint: There are 3 images.1. An old

lady

2. A young woman

3. A man with a big brown mustache

Compare this picture to the next one…

What’s the difference?

What do you see?

Does the square have curved sides?

Read this sign

What do you see?

What animal do you perceive?

A Duck, Bunny, or BOTH?

This image contains a picture and a word. Do you see both of them?

Where are those dots coming from?!

Your Your brainbrain!!

What images do you see?

Can you pick the tallest soldier?

They are all the same height!

What do you see?

The Landscape of Faces

These circles are not moving, your brain is making them appear to move. Try focusing

on one circle. It will stop moving.

Are these dots moving?

Does this image appear to be moving?

• It’s NOT!

• Just kidding, this one is actually moving

THE END

Warm up: Observation vs Inference

• List 3 Observations

• List 3 Inferences

Observation vs Inference

• List 3 Observations

• List 3 Inferences

Review: metric unit prefixesPrefix Symbol Factor Numerically NameGiga G 109 1 000 000 000 billion Mega M 106 1 000 000 million kilo k 103 1 000 thousand Deca D 101 10 ten deci d 10-1 0.1 tenthcenti c 10-2 0.01 hundredthmilli m 10-3 0.001 thousandth micro μ 10-6 0.000 00 millionth nano n 10-9 0.000 000 001 billionth