Measuring Mass and Weight 7.1.5

A little review from yesterday… - write these down What kind of force is gravitation? Contact force Force of Motion Electrical Force At-A-Distance Force When would gravity increase? When you stand on a high mountain. When you dive deep into the ocean. When you travel to a planet with larger mass. When you travel to a planet with smaller mass.

So how do we measure gravity? We use tools called scales! Technology baby!

How to use a spring scale: Watch your teacher demonstrate, or click on the picture to launch the video. Measures force in Newtons (N) by determining how much an object stretches the spring.

How to use a digital scale: Watch your teacher demonstrate, or click on the picture to launch the video. Uses the weight of an object to calculate its mass in grams (g).

How to use a triple beam balance: Watch your teacher demonstrate, or click on the picture to launch the video. Measures mass in grams (g) by comparing an object’s mass to the mass of the sliders.

Picture Property Measured Units How does it work? Spring Scale Weight Newtons (N) An object stretches the spring Digital Scale Mass grams (g) Uses the weight of an object to calculate mass Triple Beam Balance Compares the mass of an object to the mass of the sliders

Hands on practice using scales… 4-Put the object back, then select a different object. 5- Repeat until you have measured 4 different objects 6-Tape it into your note book 1- Select an object from the “junk drawer.” 2-Measure the object using an electronic scale a spring scale a triple beam balance 3- WRITE IT DOWN !

DAY #2 Exploring Mass and Weight

Sketch this chart carefully in your note book:

Which of the scales would read the same on another planet? Why? Right - The triple beam balance would read the same anywhere in the universe. The triple beam balance would read the same because it is just comparing the mass of two things. Gravity has nothing to do with the measurement.

What are the differences among mass and weight and gravity? Measures how much matter is in an object Measured in grams Changes when you remove part of the object or add to the object

What are the differences among mass and weight and gravity? Measures how much gravity pulls on something Measured in Newtons Changes when you go to another planet or by changing the mass of something.

What are the differences among mass and weight and gravity? Measures the force of attraction between the mass of two objects in a system. Measured in Newtons Changes when the mass of a planet changes OR When the distance between the planets change.

Sketch this chart carefully in your note book: How much matter is in an object grams (g) You remove part of the object or add to it…(cut off an arm or leg) How much gravity pulls down on something Newtons (N) When you go to another planet Earth vs. Moon When the mass of the planet changes or when the distance between the 2 objects change The force of attraction between two objects in a system Newtons (N)

So why do we say we weigh _____pounds? A bathroom scale is a type of spring scale. 1 pound =.45 kilograms 100 pounds=45 kilograms

1 pound=4.4 Newtons 100 pounds=440 Newtons We know from Newton’s 2nd Law that f=ma So, m=f/a a= acceleration due to gravity on earth 9.8m/ 𝒔 𝟐 so, mass = 440 N ÷ 9.8m/ 𝑠 2 44.897~45 kg

Here are some songs to help you remember what you learned today about mass, gravity, and weight

Let me know which one of these songs is your favorite!