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Measurements In Science.

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Presentation on theme: "Measurements In Science."— Presentation transcript:

1 Measurements In Science

2 A MEASUREMENT includes both a number that identifies how many units there are and a unit of measure.
Example: 2 cups Scientific experiments often involve taking measurements.

3 Most scientific studies and experiments use a standard system of metric units called Le Système International d’Unités, or SI for short. SI - modern version of the metric system based on a decimal system that uses the number 10 as the base unit. SI Base Units

4 Length inch foot yard Mile mm cm m km The Meter (m) measures length.
English inch foot yard Mile Metric mm cm m km 1 mile = 5,280 feet 1 kilometer = miles 1 mile = kilometers

5 The meter can be divided into 100 equal parts called Centimeters (cm).
A millimeter (mm) is smaller than a centimeter. There is 10mm in 1cm. Long distances are measured in kilometers (1000 m). How many mm’s are in a meter? 100 cm X 10 mm 1000 1000 mm

6 Weight measure of the gravitational force on an object.
varies with location (ex. Moon). Metric Unit = Grams (g), milligrams (mg) . Typically measured with a spring scale.

7 If you weighed 100 lbs… Mercury Venus Earth Moon Mars 37.8 90.7 100 16.6 37.9 Jupiter Saturn Uranus Neptune Pluto Earth's Moon is larger than Pluto. The Moon's diameter is 3476 km while Pluto's is approximately 2,274 km. Gravity is influenced by mass and size. Why venus same as mars and uranus similar to venus? Due physics and to newton’s inverse square law Newton's Law of Universal Gravitation says that everything that has mass attracts every other thing that has mass, pulling with a force (a) directly proportional to the product of the two objects' masses and (b) inversely proportional to the square of the distance separating their centers. In other words, although gravity increases linearly as objects grow more massive, it decreases exponentially as the distance between them increases (a phenomenon known as an inverse-square law). When calculating surface gravity, that distance refers to the space separating you (on the surface) from the planet's center of mass. This means that a planet's size actually has a greater relative impact on its gravity — and on your weight on its surface — than does its mass. Written as a formula, Newton's gravitation law looks something like this: F = G((Mm)/r2) Where F is the gravitational force between two objects, G is the Gravitational Constant (6.674×10-11 Newtons x meters2 / kilograms2), M is the planet's mass (kg), m is your mass (kg), and r is the distance (m) between the centers of the two masses (the planet's radius). Without getting too bogged down in the math, we can see that this leads to a surprising result. Take the most massive planet in the solar system, Jupiter, which tips the scales at 316 times the mass of the Earth. You might imagine you would weigh 316 times as much there as here. However, because Jupiter's radius balloons to roughly 11 times as large as Earth's, its gravitational force drops off by a factor of 1/112 at its surface (assuming you could find a way to stand on gas clouds). [Read: Would Humans Born On Mars Grow Taller than Earthlings?] 236.4 106.4 88.9 112.5 6.7

8 Weight English Metric ounce pound ton Grams Milligrams
1 newton = pounds force Weight is measured with any device whose response to a range of force is known.

9 Mass amount of matter in an object.
Depends on the numbers and kind of atoms that make up an object. Does not change with an object’s location.

10 English Metric The SI unit of mass is the kilogram (kg). pounds
milligrams grams Kilogram Can be measured with a balance. mass is measured with a Triple Beam Balance. You measure the container it is in. Fill the container with whatever you need . Subtract the weight of the container and add a g on the back of the number representing grams. In truth, NO DEVICE can measure the force of gravity. There are devices that can measure forces, but not the force of gravity directly. We call such devices: scales...and scales differ from balances since the spring scale was invented by Robert Hooke. Scales in their classical design use elasticity and deformation as a reference for force. They do not measure the force of gravity. They measure the CONSTRAINT FORCE that keeps a body stationary in its immediate environment.

11 Spring Scale Balance Scale
On earth the spring scale reads 100g with an unknown mass attached at the bottom. To balance the balance scale on the right how many grams would be needed? If we were to take both scales to the moon, what would the spring scale read (moon has 1/6th the gravity of Earth)? How much mass would be needed to balance the 100g mass on the balance beam? Can you explain your answer? See if you are right by completing the questions below. Spring Scale Balance Scale Shown below are two types of scales commonly used in the classroom --a spring scale (left) and a simple balance beam scale on the right. 16.6 spring scale and 100 g balance scale

12 Volume amount of space an object takes up.
For example, an inflated balloon takes up more space than an empty balloon.  (A balloon that is blown up has more volume than one that hasn’t been blown up)

13 Volume = Length x Width x Height
SI measurements for liquid volumes are usually made in milliliters (mL) or liters (L). English drop tsp tbsp Cup Gallon Pint Metric mL liter Volume = Length x Width x Height 1 US gallon = liters

14 Beakers Many ways to calculate volume.

15 Erlenmeyer Flasks

16 Graduated Cylinders

17 Test Tubes

18 Volumetric Flasks

19 Which object is more dense?
Density Which object is more dense? Describes the degree of compactness of a substance. In other words…how closely are the atoms packed together. More atoms in a given space = dense Less atoms in a given space = less dense

20 Which two factors determine Density?
Mass = a measure of the amount of atoms Volume = the space that the atoms take up Mass = grams Volume = mL or cm3 (1ml = 1 cm3) Expressed in grams per cubic centimeter (g/cm3) calculated by dividing the mass of an object by its volume


22 Time Time is the interval between 2 events and is measured with a watch or clock. SI unit of time is the second.

23 To calculate Fahrenheit to Kelvin:
Temperature English Fahrenheit Metric Celsius Kelvin Temperature is a measure of the average vibrations of the particles that make up a material. (ex. solid, liquid, & gas) SI unit for temperature is the Kelvin (K) scale. On this scale the coldest possible temp is absolute zero or 0 K – which is equal to -273° C. To calculate Fahrenheit to Kelvin: 1st °C = (°F - 32) / (1.8) 2nd K = °C

24 Solid = tightly packed, regular pattern, vibrate (jiggle) but don’t move from place to place
Liquid = close together, no regular arrangement, vibrate, move about and slide past each other Gas = well separated, no regular arrangement, vibrate and move freely at high speeds

25 To calculate Celsius to Fahrenheit:
°C  x  9/ = °F To calculate Fahrenheit to Celsius: (°F  -  32)  x  5/9 = °C

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