Presentation on theme: "Chapter Two: Science Skills 2.1 Mass and Volume 2.2 Density 2.3 Graphing 2.4 Solving Problems."— Presentation transcript:
Chapter Two: Science Skills 2.1 Mass and Volume 2.2 Density 2.3 Graphing 2.4 Solving Problems
2.1 Measuring mass Mass describes the amount of matter in an object. The SI unit for mass is the kilogram (kg). The kilogram is too large a unit to be convenient for small masses. One gram (g) is one-thousandth of a kilogram. What is the estimated mass of ONE zinc nut?
2.1 Mass and weight are different We tend to use the terms mass and weight interchangeably, but they are not the same thing. Mass is the amount of matter in an object. Weight is a measure of the pulling force of gravity on an object.
2.1 Mass and weight are different A 2.3 kg bag of flour has a mass of 2.3 kilograms no matter where it is in the universe. The weight of the bag of flour is less on the moon. The 5 lb bag of flour on Earth weighs only.8 lbs on the moon!
2.1 Volume Volume is the amount of space an object takes up. The fundamental unit of volume in SI is the cubic meter (m 3 ). More convenient smaller units are cubic centimeters (cc or cm 3 ), liters (L) and milliliters (mL).
2.1 Displacement You can find the volume of an irregular shape using a technique called displacement. Put the irregularly shaped object in water and measuring the amount of water displaced.
2.1 Comparing mass and volume Mass and volume are two different properties of matter. Size does not always indicate an object’s mass! How the matter is packed into space is more important.
2.2 Density Density describes how much mass is in a given volume of a material.
2.2 Density The units used for density depend on whether the substance is solid or liquid. For liquids use units of grams per milliliter (g/mL) For solids use density in units of g/cm 3 or kg/m 3.
2.3 How to make an XY graph 1.Choose/label x and y-axis independent variable = x axis dependent variable = y axis 2.Make a scale Most graphs use ones, twos, fives or tens OR calculate the value per box 3.Plot your data 4.Seek the pattern- (best fit line) 5. Title of graph
Calculate marble’s volume & density 1.Looking for: volume, then density 2.Givens: mass = 6 g, water displaced 30 to 32 mL 3.Relationships: water displaced = marble volume, D = m/V 4.Solution: 32 mL – 30 mL = 2 mL D = 6 g / 2 mL = 3 g/mL Solving Problems
2.4 How to solve design problems Use what you know to design a solution that solves the problem. Unlike “formula problems,” design problems have many correct solutions. The solutions are only limited by your creativity, ingenuity, skill, and patience.
2.4 How to solve design problems What does your design need to accomplish? What constraints do you have? Think of an idea. Follow the design cycle…
Density and Ocean Currents Did you know that there are underwater waterfalls in the ocean? While it may seem strange for water to fall through water, it really happens due to density differences in ocean water coming from different sources.