4th Science Study Guides - Unit 2 - Mixtures and Solutions
Dissolving:
- When a solid breaks into pieces so small and becomes part of a liquid. Solids will dissolve faster in warmer liquids (think about sugar in sweet tea – sugar will dissolve faster in hot water than if you add sugar in a cup of cold tea)
Mixtures:
- When 2 or more substances are mixed together and can be easily separated. Ways to separate (by hand, with tweezers, with a strainer, with a magnet). Think about the mixtures you brought or examples from lab (lucky charm baggie, sand and gravel, wood and water). Mixtures are not evenly dispersed (spread out). Substances in mixtures maintain their physical properties. Mixtures are made of matter - can be solids, liquids, and gasses.
- If I mix rocks, small rocks, and sand with water, the bigger items will settle to the bottom and the water will be on the top (after it has filled the cracks)
Solutions:
- A special kind of mixture with 2 or more substances and one of the substance dissolves in a liquid
- Solutions CAN be separated, but it is harder (EX: saltwater – evaporate the water and you are left with salt)
- Other examples: lemonade, sugar water, baking soda and vinegar
- Substances are evenly dispersed (spread out) – it looks like one substance
Equipment Review:
- Hand lens – to help see if a substance has completely dissolved
- Thermometer – measure temperature (helpful in a warmer liquid when you want a solid to dissolve faster)
- Stopwatch – can time how long it takes something to dissolve
- Tweezers – to pick up small things like pebbles (helps to separate a mixture)
- Strainer – used to separate a mixture (EX: sand and rocks)
- Magnet – used to separate metal from a mixture
Safety Practices Reviewed:
- Review all safety rules before starting an investigation or experiment
- Wear protective equipment (goggles, gloves, and aprons) as needed
- Make sure are is clean before beginning investigation
- Report a spill to your teacher FIRST before cleaning it up.
Know these vocabulary words!!!!!!!!!!
- dissolved: to become absorbed in liquid
- evaporation: the process of changing a liquid into a gas
- magnetism: a force that pulls magnetic materials across a distance
- magnetic: a force that attracts or repels iron, nickel or cobalt
- mixture: a combination of two or more substances that do not form a new substance
- separate: to set or keep apart
- solution: a mixture with one substance spread out so evenly in another substance that you cannot tell the two substances apart
4th Science Study Guides - Unit 1 - Physical Properties
If you understand this material, you will be able to relate it to STAAR (the new version of TAKS) type questions.
Physical Property: observable characteristics of matter (use your 5 senses to identify or measure them with tools)
Examples of physical properties we have discussed in class and the lab: magnetism, state of matter, density, volume, mass, color, texture, flexibility, durability, buoyancy, and shape.
States of Matter·
Buoyancy - the force that causes things to float (if you push a beach ball down in a swimming pool, it will pop back up because of the air inside – it is buoyant)
Density- the amount of mass in an object (remember we talked about relative density – if something sinks or floats compared to water)
· Objects will sink in water when they are MORE dense than water
· Objects will float in water when they are LESS dense than water
· Metals and glass tend to sink because they are more dense than water.
· Plastic and Styrofoam tend to float because they are less dense than water.
Volume –the amount of space that an object or substance takes up
· Liquid volume is found with a graduated cylinder
· Volume of a regular shaped item (like a box) is found with a ruler – length x width x height
Mass –the amount of matter in an object or substance (measured with a triple beam balance) (labeled grams)
Tools for Measuring Physical Properties
· A triple beam balance is used to measure mass.
· A spring scale measures weight (the pull of gravity on an object).
· A meter stick measures length. (Know how to read a ruler. look at your handout - Measuring Physical Properties)
· Thermometers measure temperature. Be able to read a thermometer (look at your handout - Measuring Physical Properties)
· A graduated cylinder measures liquid volume.
· Beakers also measure volume.
Safety Rules Reviewed
· Follow teacher instructions
· Do not eat, drink or smell in the lab.
· Wear goggles when working with chemicals or glass.
· Know the safety plan.
· Clean up any spills (but notify your teacher first)
· Hair pulled back, jewelry off, and dangling clothes pulled back.
Vocabulary – You are only responsible for these 10 words
Physical Property: observable characteristics of matter (use your 5 senses to identify or measure them with tools)
Examples of physical properties we have discussed in class and the lab: magnetism, state of matter, density, volume, mass, color, texture, flexibility, durability, buoyancy, and shape.
States of Matter·
- When a gas becomes a liquid after it is cooled, it is called condensation.
· Freezing - when a liquid turns into a solid
· Melting - when a solid absorbs heat energy and turns into a liquid
· Boiling - when a liquid absorbs heat and turns into a gas
Buoyancy - the force that causes things to float (if you push a beach ball down in a swimming pool, it will pop back up because of the air inside – it is buoyant)
Density- the amount of mass in an object (remember we talked about relative density – if something sinks or floats compared to water)
· Objects will sink in water when they are MORE dense than water
· Objects will float in water when they are LESS dense than water
· Metals and glass tend to sink because they are more dense than water.
· Plastic and Styrofoam tend to float because they are less dense than water.
Volume –the amount of space that an object or substance takes up
· Liquid volume is found with a graduated cylinder
· Volume of a regular shaped item (like a box) is found with a ruler – length x width x height
Mass –the amount of matter in an object or substance (measured with a triple beam balance) (labeled grams)
Tools for Measuring Physical Properties
· A triple beam balance is used to measure mass.
· A spring scale measures weight (the pull of gravity on an object).
· A meter stick measures length. (Know how to read a ruler. look at your handout - Measuring Physical Properties)
· Thermometers measure temperature. Be able to read a thermometer (look at your handout - Measuring Physical Properties)
· A graduated cylinder measures liquid volume.
· Beakers also measure volume.
Safety Rules Reviewed
· Follow teacher instructions
· Do not eat, drink or smell in the lab.
· Wear goggles when working with chemicals or glass.
· Know the safety plan.
· Clean up any spills (but notify your teacher first)
· Hair pulled back, jewelry off, and dangling clothes pulled back.
Vocabulary – You are only responsible for these 10 words
- boiling point: the temperature at which a substance changes from a liquid to a gas
- density: is the amount of mass in an object
- magnetism: a force that pulls magnetic materials across a distance
- mass: the amount of matter in an object or substance
- matter: the material, or stuff, that everything is made of
- melting point: the point at which a solid changes to a liquid
- properties: a quality or attribute, especially one that serves to define or describe something
- states of matter: forms that matter can take – solid, liquid, or gas
- temperature: the average speed of the particles in a substance
- volume: the amount of space that an object or substance takes up