Skills Unit Science Test

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Scientific Method: A step by step approach to solving problems in science.

Purpose: State the problem investigated

Hypothesis: Make a prediction about the problem studied

Materials: List of materials needed to test hypothesis

Method: List of steps followed to test hypothesis

Observations: Record of what occurs during the experiment (sight, smell, texture, taste, sound)

Discussion: Explanation of the results and possible errors found

Errors: List of errors that occurred during the experiment

Conclusion: State is your hypothesis is right, wrong or inconclusive and why

Two variables (Thing that changes) should be mentioned

Independent Variable: The factor that is changed by the experiment

Dependent Variable: The factor that is measured by the independent variable

Controls

Can influence the dependent variable

These conditions must be kept constant or controlled for results to be valid

In an experiment, only one variable is changed, and others are kept constant to find out what effect occurs

Example: An experiment is conducted to see if temperature affects the evaporation rate of water

Independent variable: Temperature

Dependent variable: Quantity of water/ unit of time

Controls: Starting volume,

Container

Hypothesis: If temperature is increased then the rate of evaporation will increase

Observations

A statement of fact about an object

Qualitative and Quantitative data of what happens during experiment

Example: The apple is red, the car is black

Qualitative Data

Information you get using your senses

Sight, smell, texture, taste, sound

Quantitative Data

Based on measurement, time or volume

Observations should record:

Reactants: Material at the start of the reaction

Products: Materials at the end of the reaction

Reaction: What occurs during the reaction

Inferences: A summary statement at the start of the reaction made by using your past knowledge. A description of the observation that may or may not be true.

Example: All sports cars drive over the speed limit

Summary or Conclusion of the observations

Mass: A measure of the amount of matter in a sample or substance

Generally measured in grams or kilograms

Should not be confused with weight

Can be measured with a balance

Using A Balance

Ensure the balance is set at zero when starting (Tare button to clear)

If you are measuring a powder or liquid add the substance being measured to the container and subtract to determine the mass of the substance

Example:

Mass of container: 100 grams

Mass of container w/salt: 105.0 grams

Mass of salt: 5.0 grams (105.0-100.0 grams)

Volume: A measure of the amount of space occupied by a sample of matter

Measured in cm3 or m3 for solids, measured in mL or L for liquids

Regularly shaped objects can be measured using (V= L x W x H)

Liquids can be measured using a granulated cylinder

(hint: always measure from the bottom of the meniscus which is the curve on the surface of the liquid)

*read spot on bottom of curve*

Irregular objects can be measured using the water displacement method

Put water into a granulated cylinder, drop the object into the cylinder and find change in volume

1 cm3 = 1 mL

V= 29mL – 19mL V=67 – 64

V= 10mL V = 3mL

V=10cm3 V= 3cm3

Archemois Principle

Slope: A line that shows a relationship between two variables

Change in Y axis= Distance the line goes Up= Rise

Change in X axis= Distance the line goes Across= Run

Rise (Distance up the Y-axis)

Run (Distance along the X axis)

Density: The amount of matter that occupies a certain space (Mass per unit volume)

Mass- Amount of matter

Volume- Amount of space occupied by the matter

Density of water

1 g/mL, 1 g/cm3, 1 000 kg/m3

Anything with a density lower than this will float on water

g/mL, g/cm3, kg/m3

Density = Mass divided by Volume

Mass = Density x Volume

Volume = Mass divided by Density

GHS (Adopted by Canada – 2015)

Global

Harmonized

System of classification and labelling of chemicals

Universal Safety Symbols found on dangerous products in the lab.

A supplier label must have:

an identification of the product

a signal word – Danger or Warning where necessary

precautionary statements indicating how the product should be handling to minimize risks

the identity of the supplier

Compressed Gas

Contents under high pressure. The cylinder may explode or burst when heated, dropped or damaged.

Flammable

May catch fire when exposed to heat, spark or flame. May burst into flames

Oxidizing Agent

May cause fire or explosion when in contact with wood, fuels or other combustible material.

Poisonous

Poisonous to swallow, inhale and/or bring into contact with skin.

Harmful

May cause skin or eye irritation.

Explosive

Self-reactive substances, unstable explosives.

Corrosive

Can cause burns to eyes, skin or respiratory system.

Environmental Hazard

A danger to the aquatic environment.

Health Hazard

May cause respiratory distress. A possible carcinogen or may damage organs with one or more exposure.

HHPS

Hazardous

Household

Product

System

Universal Safety Symbols found on dangerous products in the home

A supplier label must have:

an identification of the product

a signal word – Danger or Warning where necessary

precautionary statements indicating how product should be handling to minimize risks

the identity of the supplier

There are two frames used around the symbols:

The container is dangerous

The contents of the container are dangerous

Symbol

Meaning

Description

Explosive

This container can explode if it’s heated or punctured. Flying pieces of metal or plastic can cause serious injuries, especially to the eyes.

Corrosive

This product will burn skin or eyes on contact, or throat and stomach if swallowed.

Flammable

This product, or its fumes, will catch fire easily if it is near heat, flames or sparks.

Poisonous

Licking, eating, drinking, or sometimes smelling this product will cause illness or death.