Metric System Mass & Weight What's the difference? Units & Measurement Tools Reading a Balance

Review What are two advantages to the metric system? 1.Scientists can share & compare data 2.All units are based on the number 10.

Review Match the phrase with the correct term. 1.The SI unit for Volume e) liter 2.The SI unit for Length a) meter 3.The SI unit for Mass b) gram 4.The SI unit for Temperature c) Celsius 5.The SI unit for Weight d) Newton a)Meter b)Gram c)Celsius d)Newton e)Liter

SI Prefixes

Mass Amount of matter in an object –how much stuff an object is made of Compare a basketball & a bowling ball. Even thought they’re about the same size (volume!), they have totally different masses.

Mass Units: gram (g) or kilogram (kg) Think About –1 science book = 1.3 kg –1 large paperclip = 1 gram –1 ml of water = 1 gram

Mass Measurement Tool: triple-beam balance The object’s mass is compared to the balance’s weights

Labeled Balance

Using a Triple Beam Balance We’re going to use these in the lab today. PLEASE BE CAREFUL. They break really easily.

You Try It! Reading a Balance 1. What does this balance read? 155 grams

You Try It! 2. What does this balance read? grams

You Try It! 3. What does this balance read? grams

Mass Is it affected by gravity? NO!!! Whether on the moon or on Earth, your mass remains the same.

Weight The downward force of gravity acting on an object –On Earth, the word “weight” refers to Earth’s gravitational force on an object. –But “weight” can be applied to any amount of gravity on any planet

Weight Unit: Newton (N) or Pound (lb) Think About: –A medium apple = 1 N –A paperback book = 1 lb Measurement Tool: spring scale

Weight Is it affected by gravity? YES!!! Weight is a measure of the force of gravity. More gravity? More weight! Less gravity? Less weight!

Your Weight on other Worlds If you weigh 100 pounds… ObjectGravitational Pull (N) Your Weight (lb) Mercury lb x = 37.8 Venus0.907 Luna0.166 Mars0.379 Jupiter2.36 Pluto0.067 Our Sun27

Your Weight on other Worlds ObjectGravitational Pull (N) Your Weight (lb) Mercury lb x = 37.8 Venus Luna Mars Jupiter Pluto Our Sun272700

Finding the Mass of a Liquid As a group, discuss the following. How do you find the mass of 50 mL of water? Can you come up with 3 ways? Record your idea in the space.

Finding the Mass of a Liquid 1.Find the mass of an empty container, then with water, subtract 2.Place the container on the balance, calibrate it, then find the mass of the water 3.1 ml water = 1 gram, so 50 ml = 50 grams