8 th Grade Advanced Science Midterm Study Guide

Transcription

1 Observing vs. Inferring Observations are Inferences are You can use your observations to make inferences. Observation: Maya is wearing a pink shirt, pink pants, and has a pink backpack. Inference: Maya likes the color pink. Inferences are based on observations. They are an explanation of your observations. Mass, Volume, Length, Density Mass is measured with a and the unit is Volume can be measured with a ruler using the volume formula x x Or volume can be measured with a graduated cylinder. This is called Final volume- initial volume = volume of the object. Density measures the amount of in a given. The formula for density is divided by. Or D= m/v Mass vs. Weight Mass is not the same as. Weight is the measure of how much is pulling down on you. Your weight can change if you move locations, but your stays the same. Mass is a measure of how much is in an object. Replication and Repetition: Replication is when another scientist copies your experiment to check for accuracy and look for mistakes. Repetition is sometimes called repeated trials. Repetition is when you the experiment to look for mistakes and check for accuracy. Scientific Experiments and Scientific Investigation Science experiments require you to actively test your hypothesis by doing an A scientific investigation does not require an instead you might do research, make a model, or just collect data through making observations with your five Steps of the Scientific Method 1. Identify the (You usually write this in the form of a question) 2. Make with your five senses and then use your observations to make an that explains your observations. 3. Form a hypothesis. Your hypothesis is usually written as an If then because statement. 4. Identify your (IV, DV, and ) 5. Test your in an experiment or 6. Collect by making observations. 7. Analyze your and create a model (usually a chart or of your data) 8. Draw a that explains your results and tells if your hypothesis was supported or.

2 Scientific Explanation (conclusion) Your conclusion explains your and tells if your hypothesis is supported or unsupported. What do you use as evidence in your conclusion? Empirical evidence is or collected in an experiment or investigation. Empirical evidence is used to support or un support your hypothesis Theory vs. Law Theories are Laws Theories must why something happens. Ex) Theory of change over time explain why organisms adapt to be better suited to their surroundings. Laws do not Laws tell what happened. Laws explain an observed in nature. Ex) Law of gravity says what goes up must come down. If you throw something into the air it will always The Theory of the Atomic Model says: Everything is made up of and atoms make up. Therefore, everything is made of Atoms are the smallest unit of any. Atoms are made of sub atomic particles called,, and. Theories can change! The atomic model many times as we got new and better. The current atomic model says that the nucleus is very small and It also says that and are found in the nucleus. are found in electron shells and they around the nucleus. We know the protons have a charge. The electrons have a charge. And the neutrons are, meaning they have no. The current model states that the electrons move so fast we cannot see them and instead we call the moving electrons an electron. The atomic model could change again if Physical vs. Chemical Properties Physical properties are of matter measured through _ Physical properties of matter do not or bonds. Examples of physical properties are: color, texture, size, magnetism, density, malleability, mass, electrical and heat conductivity, and solubility. Physical properties allow us to compare and classify Chemical properties and bonds. Chemical properties will create a substance. Chemical properties are only observed when the substance undergoes a change and becomes a new substance.

3 The four states of matter are: In solids particles are packed and the volume and shape are. Solids have a greater because the particles are tightly packed in a specific volume. In liquids the particles are tightly packed. In liquids particles can and this allows a liquids shape to Liquids have a fixed but not a fixed shape. Elements: Elements are found on the Elements are pure substance because they only contain type of. Elements can to make molecules and compounds. The periodic table is organized into that are the vertical columns and periods that are Elements in the same group or share similar including the number of valance A Lewis dot structure tells you the number of You draw one dot for each. Lewis dot structures help us determine if elements will Draw dot structures for H In gasses, the particles are. The particles move quickly and spread. Gasses have no fixed or. Gasses are less d than solids. Plasma is an gas. Plasma is when the elctrons contain so much they break free from the shell and move away. We find plasma in > The periods of periodic table show how element properties repeat in a created the periodic table. The periodic table is organized by increasing atomic. When you look at an element you will see the element name, symbol, atomic and atomic The atomic number tells us the number of and. The atomic mass the atomic number tells us the. Ex) oxygen has an atomic mass of 16 8 (the atomic #) = 8 neutrons F O

4 Ionic bonds form between and Ionic bonds transfer The metal is the The metal is the ion The nonmetal is the The nonmetal is the ion An ionic compound is The signs or charges Mg + F = ph Scale The ph scale measures from to 0 - are acids ph of 7 is ph above 7 to 14 is Substances that are acidic release ions. Substances that are basic release ions. Covalent bonds do not form Covalent bonds do not transfer electrons they _ Covalent bonds produce compounds. In a covalent bonds the elements move so close together that the valance shells The electrons in the overlap are shared as long as the atoms are together. When the electrons are shared each atom/element has a valance shell. Ex) Cl + Cl = Mixtures can be or A homogenous mixture is sometimes called a A solution is a A heterogeneous mixture is called a mixture because it is not the throughout. The law of conservation of mass says 1. Matter cannot be 2. Matter cannot be 3. Matter can be 4. When matter is transformed the physical and chemical can change, but the must stay the same. Solute: is what is being in a solution. Ex) koolaid powder Solvent: is what is doing the in a solution. Ex) water to dissolve the koolaid Solubility: is the amount of solute that can be by the solvent. Ex) The koolaid and water combined.

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