Science End-term Review - PDF

Science End-term Review  Agenda Review weeks 1 - 10 science The Scientific Method & Fair Testing Atoms and Elements 1 & 2 Introduction to Respiration Plants: Germination and Growth Plants: Transpiration and Transport of Nutrients Acids and Alkalis The Scient...

Science End-term Review  Agenda Review weeks 1 - 10 science The Scientific Method & Fair Testing Atoms and Elements 1 & 2 Introduction to Respiration Plants: Germination and Growth Plants: Transpiration and Transport of Nutrients Acids and Alkalis The Scientific Method & Fair Testing  PPE Safety goggles Mask Ear plugs / hearing protection Safety gloves Closed-toe shoes Hair net / helmet Lab coat  Lab Safety Can you guess what the symbols mean? CORROSIVE TOXIC HIGHLY Substances that Can cause death FLAMMABLE attack and destroy when swallowed, Substances that living tissues, breathed in or easily catch fire. including the eyes absorbed through and skin. the skin.  Scientific Method Observation Hypothesis The Scientific Method is used to solve problems Prediction and questions. Experiment Data  Fair Test A fair test is an experiment where only one variable is changed, and all other variables are kept the same. Three types of variables involved in a fair test are: Independent Dependent Control variable variable variable  Fair Test In a fair test, the dependent variable is “dependent” (relies) on the independent variable. Control Independent Dependent Variables Variable Variable One independent variable is changed at a time while the rest of the variables are controlled. Atoms and Elements 1 & 2  Atoms and Elements An element is any substance made of only one type of atom. For example: Carbon is an Copper is an Helium is an element made of element made of element made of only carbon atoms. only copper atoms. only helium atoms.  Compounds A compound is a substance formed when two or more chemical elements are chemically bonded together. The elements in compounds are always present in fixed ratios. Compounds can be broken down into the elements that make them, but only using chemical reactions. CO2 is always 1 carbon:2 oxygen Examples: H2O (water), CH4 (methane), What are some examples of compounds? NaCl (salt), C6H12O6 (glucose/sugar).  Metals, Non-Metals and Metalloids Non-metals are on the right. Metals are on Metalloids are the left. Most of between the metals the elements are and non-metals. metals.  Common Elements ? ? ? ? ? ? ? ?  The Periodic Table The periodic table is organised by horizontal rows, and vertical columns. The horizontal 0 rows are called 3 4 5 6 7 periods. The vertical columns are called groups.  Periods The horizontal rows are called periods. There are 7 periods in the periodic table. All the elements in a period share the same number of electron shells (energy levels). For example, all of the elements in period 4 have 4 7 periods electron shells (levels).  Groups The vertical columns are called “groups” (sometimes called families). There are 18 groups in the periodic table. groups All elements in a group have the same number of valence electrons (outer electrons). For example, all of the elements in group 2 have 2 valence electrons (outer electrons). This means the elements in each group share similar chemical and physical properties.  Shell Models If we know the number of shells and how many valence electrons, we can find which group and period the element is in. Example: Magnesium It has 3 electron shells = 3rd period It has 2 valence electrons = 2nd group Remember: Valence electrons are the electrons in the outermost shell.  Shell Models You try: What is the period and group for these elements? 1 electron shell 2 electron shell 3 electron shell = period 1 = period 2 = period 3 1 valence electrons 7 valence electrons 8 valence electrons = group 1 = group 7 = group 8  Physical Properties The physical properties of an element don't involve changing the chemistry of the element. Physical properties can be observed using our senses and measured numerically. Examples of physical properties include: colour freezing/boiling/melting points density smell  Chemical Properties Chemical properties are when there is a change in the structure of the element. Chemical properties are only observable during a chemical reaction. Elements in the same group have similar chemical properties. Introduction to Respiration Breathing in - inhalation Intercostal muscles contract pulling the chest walls up and out. The diaphragm contracts and moves down. The lungs increase in size, causing air to rush in from the nose or mouth. Breathing out - exhalation Intercostal muscles relax, pushing the chest walls down and in. The diaphragm muscle relaxes and bulges up. The lungs decrease in size, so air is pushed out through the nose or mouth.  The Air Amount in inhaled Amount in exhaled Gas air air oxygen 21% 16% carbon dioxide 0.04% 4% nitrogen 78% 78% water vapour Variable Plants: Germination and Growth  Germination Factors 1. Water 2. Oxygen 3. Temperature The optimal After water temperature for Water activates wakes up the germination enzymes that use seeds, they need varies between oxygen and oxygen to start plants. But, all stored food making energy in seeds must have (sugar/starch) to cellular some soil warmth. make energy. respiration.  Functions of Parts of a Leaf Waxy layer Large surface area A waterproof layer that stops Maximise light exposure. water loss out of the leaf. Chloroplasts Stomata Cells are long and have Pores that open and lots of chloroplasts to close to allow CO2 in, maximise photosynthesis. and water and O2 out.  Xylem and Phloem Two-way One-way flow flow Transports water Transports and minerals glucose No end walls End walls (seive between cells plates) Outer cells are Outer cells are not living living but need support  6 Steps of germination and growth Seed Embryo Embryo absorbs breaks sends root water through down into from soil. seed coat. soil. 6 Steps of germination and growth Shoot grows Seedling Seedling starts up above the grows into to grow leaves. soil. mature plant. Plants: Transpiration and Transport of Nutrients Plant Nutrients Nutrients: The minerals that plants need which allow them to complete chemical reactions to live. There are at least 17 essential minerals needed for healthy plants. 4 important minerals for plants Nitrogen (N) For making Phosphorous (P) For healthy proteins flowers and and healthy fruit growth Potassium (K) For healthy Magnesium (Mg) For making roots chlorophyll  Fertilizers Fertilizers are substances that contain nutrients to help crops grow well. They can increase the farmer’s crop yield. Using fertilizers helps crops grow faster, bigger, and overall it increases the farmer’s crop yield. Yield = how much food farmers get from their land Water and Mineral Transport 3 Steps 1. Osmosis 2. Capillary Action - adhesion - cohesion 3. Transpiration Step 1: Osmosis Water and nutrients are absorbed into the root hairs and roots from the soil. Step 1: Osmosis Water moves into roots by osmosis. Osmosis is the movement of water from an area of more water to an area of less water. Step 2: Capillary Action Capillary action is when water moves through the narrow spaces of a material because of adhesion and cohesion. Step 2: Capillary Action Cohesion Adhesion Water molecules Water molecules stick stick to other to other substances, water molecules like the xylem vessels! Acids & Alkalis Common Acids and Alkalis End of Review