Scientific method

Section 1.1

Observation: a piece of information we gather using our senses (sight, hearing, smell and touch)

Science usually begins with observations◦ Qualitative observations

◦ Quantitative observations

Quantitative – measureable or countable◦ 3 meters long

◦ 4 marbles

◦ 50 kilograms

◦ 35 degrees Celsius

Qualitative – describable, not measureable ◦ I see red flowers.

◦ It smells like fresh baked cookies in here.

◦ This feels cold!

◦ This sounds really loud.

Inference: A conclusion reached on the basis of evidence and reasoning.

We don’t observe an inference. We use observations to create inferences.

Conclusions or deductions based on observations.

The process of drawing a conclusion from given evidence.

Practice!!

Observations:

• I hear people screaming

• I smell cotton candy, popcorn, and hamburgers

• I see a lot of people

Inference = ?

Look at these two sets of animal tracks.

List 3 OBSERVATIONS

Make an INFERENCE

Make an INFERENCE

Make 3 OBSERVATIONS

Make 3 OBSERVATIONS

Make an INFERENCE

Observations almost always lead to more questions.

Scientists form a hypothesis for their observations.

Hypothesis: a tentative explanation for an observation. ◦ A hypothesis is NOT a guess. It should make

logical sense and build on knowledge about an observation.

Scientists perform experiments to test a hypothesis under controlled conditions. ◦ Experiments pinpoint cause-and-effect

relationships.

A good experiment should have:◦ An independent variable

◦ A dependent variable

◦ Other variables held constant

◦ Most experiments will have a control

Independent variable: The variable you purposely change or manipulate.

The independent variable is the CAUSE of the changes you measure.

What is causing a change in this investigation?

The variable that responds. Also called the responding variable. The variable that you will measure after the experiment is set up.

The number of times a specific experiment is repeated.

A good experiment will have more than 1 trial.

All other variables that remain the same for all the trials.

A group that does NOT contain the independent variable. The NO TREATMENT group or NORMAL TREATMENT group. Gives you a way to detect hidden variables.

1. Nick wanted to see how high an ice cube would float in different temperatures of water. Identify the dependent variable.

Amount of Water

Height of Ice Cube

Temperature the ice cube was at its highest height

Temperature of the water

Size of the Ice Cube

#1. Height of the Ice Cube

#2. Mario studied how far room temperature water would spurt out of a plastic milk carton when 3mm holes were punched at different heights from the bottom of the container. Identify the dependent variable.

3mm Holes Distance Water Traveled Out Of Carton Different Heights of the Holes in the

Container Ice Water From Iceland

#2. Distance Water Traveled Out of Carton

#3. Mr. McNiece wanted to see how different types of music affected students' pulse rates. he played different types of music: heavy metal, rap, R&B, alternative, pop, country, and classical music. What constant should be considered when doing this experiment?

Amount of time the music was played Use all dead people Using a different student for each music type Types of music

#3. Amount of Time the Music was Played

#4 Tiffany was investigating how fast it took Hayden to react to different sounds. Identify the dependent variable.

Hayden

How fast Hayden reacted

How much time it took Hayden to react

Different sounds

#4. How much time it took Hayden to react

#5. Mario studied how far room temperature water would spurt out of a plastic milk carton when 3mm holes were punched at different heights from the bottom of the container. Identify a constant.

Ice water from Iceland

3 mm holes

Different heights of holes in container

Distance water traveled out of carton

#5. 3 mm holes

#6. Mario studied how far room temperature water would spurt out of a plastic milk carton when 3mm holes were punched at different heights from the bottom of the container. Identify the independent variable.

3 mm holes

Distance water traveled out of carton

Different heights of holes in container

Ice water from Iceland

#6. Different heights of holes in container

#7. Mr. McNiece wanted to see how different types of music affected students' pulse rates. He played different types of music: heavy metal, rap, R&B, alternative, pop, country, and classical music. Identify the independent variable.

Mr. McNiece

Classical music resulted in the highest pulse rate

High pulse rate

Types of music

Pulse rate

#7. Types of music

#8. Tiffany was investigating how fast it took Hayden to react to different sounds. Identify the independent variable.

How much time it took Hayden to react

Hayden

How fast Hayden reacted

Different sounds

Playing the trumpet over and over

#8. Different sounds

#9. Nick wanted to see how high an ice cube would float in different temperatures of water. Identify the independent variable.

Temperature of water

Temperature the ice cube was at its' highest height

Height of ice cube

Size of ice cube

Amount of water

#9. Temperature of water

#10. Justin usually blows his nose using Kleenex tissues. His snot keeps leaking through the tissue. He decided he is going to create an experiment to find out if there is something better. What is a constant?

Type of tissue Justin Amount of tissue Mass of the snots the tissue can hold Kleenex

#10. Amount of tissue

#11. Mr. McNiece wanted to see how different types of music affected students' pulse rates. He played different types of music: heavy metal, rap, R&B, alternative, pop, country, and classical music. Identify the dependent variable.

Mr. McNiece

High pulse rate

Pulse rate

Classical music resulted in the highest pulse rate

Types of music

#11. Pulse rate

#12. Justin usually blows his nose using Kleenex tissues. His snot keeps leaking through the tissue. He decided he is going to create an experiment to find out if there is something better. What is his dependent variable?

Type of tissue

Mass of the snots the tissue can hold

Kleenex

Amount of tissue

Justin

#12. Mass of the snots the tissue can hold

#13. Justin usually blows his nose using Kleenex tissues. His snot keeps leaking through the tissue. He decided he is going to create an experiment to find out if there is something better. What is his independent variable?

Kleenex

Justin

Amount of tissue

Mass of the snots the tissue can hold

Type of tissue

#13. Type of tissue

#14. Justin usually blows his nose using Kleenex tissues. His snot keeps leaking through the tissue. He decided he is going to create an experiment to find out if there is something better. What is his control group?

Type of tissue Justin Amount of tissue Mass of the snots the tissue can hold Kleenex

#14. Kleenex