Let’s Review What We’ve Learned so Far…

1) Lab Safety•Can you demonstrate safe practices during lab and field investigations?•Can you demonstrate an understanding of the use and conservation of resources and the proper disposal or recycling of materials?

2) Scientific Method•What is science?•What are the steps to the scientific method?•Why is it important to have several trials in an experiment?•What are the independent and dependent variables? How do they fit in a hypothesis? What is a hypothesis?

What You Should Know:

From your assigned readings you should also

know:

• Definition of a theory: Theories are based on natural and physical phenomena and are capable of being tested by multiple independent researchers.

• Unlike hypotheses, scientific theories are well-established and highly-reliable explanations, but they may be subject to change as new areas of science and new technologies are developed.

• Can you distinguish between a scientific hypothesis and a scientific theory?

1) If I use miracle grow my plants will grow more quickly than if I use normal water.

2) Plants and animals evolve slowly over millions of years. This is supported by the fossil record as well as the living record.

3) If there are not enough animals to hunt, Wild dogs will scavenge for food.

4) Light travels at a constant speed and nothing can travel faster than light. This is defined by Einstein’s equations of relativity.

Let me pick your brain…

Theory or Hypothesis?

On to the lesson for today…

The Metric System! [start clapping out of joy]

Meters, Grams, and Liters…oh my!

Back in the day…Back in the day…• People used to use parts

of their body to determine the length of something.

• The standard would be a part of the king’s anatomy.

• The standard yard was the distance from the king’s nose to his outstretched arm

The English system is very confusing The English system is very confusing because it has so many different because it has so many different

valuesvalues

America is one of the only countries that still uses the old

English system

Scientists give the English Scientists give the English system the thumbs downsystem the thumbs down

Scientists needed an exact and uniform system of weights and measurements…

hmm

•The metric system was the answer!

•The metric system is a decimal system of measurement whose units are based on certain physical standards.

•It is scaled on multiples of 10, which makes using it super easy and a lot less confusing (Yay!)

How did the metric system How did the metric system come about?come about?

• During the 18th century, During the 18th century, scientists measured the scientists measured the distance from the earth’s distance from the earth’s equator to its North Pole equator to its North Pole and divided it into ten and divided it into ten million parts.million parts.

• This is how they came up This is how they came up with the length of the with the length of the standard meter.standard meter.

The Meter

• Meters measure length or distance.Meters measure length or distance.• The standard for the meter is kept in a safe in France.The standard for the meter is kept in a safe in France.• The meter stick is a replica of that standardThe meter stick is a replica of that standard• A meter is made up of 100 centimeters and 1000 A meter is made up of 100 centimeters and 1000

millimetersmillimeters

One millimeter is about the

thickness of a dime

How the Gram came about…How the Gram came about…

• Scientists needed a Scientists needed a standard to measure standard to measure mass. mass.

• Grams measure Grams measure mass or the weight mass or the weight of an object.of an object.

• They decided to They decided to take one cubic take one cubic centimeter of water centimeter of water and call it a gram.and call it a gram.

1 gram weighs about as much as one small paperclip.

• Liters measure volume or the amount of Liters measure volume or the amount of a liquid.a liquid.

• Scientists needed a way to measure Scientists needed a way to measure liquids so they took 10 cm and multiplied liquids so they took 10 cm and multiplied it by its length x width x height to come it by its length x width x height to come up with a standard for measuring volume.up with a standard for measuring volume.

• The liter is the size of 10 cm(3)The liter is the size of 10 cm(3)• 10cm x 10 cm x 10 cm10cm x 10 cm x 10 cm• Length x Width x Height = VolumeLength x Width x Height = Volume

How the liter came about…How the liter came about…

A 2 liter Coke bottle is…well 2

liters!

Uh Oh!Uh Oh!

Two different groups of Two different groups of scientists were working on scientists were working on the calculations to send a the calculations to send a probe to Mars.probe to Mars.

The American team did their The American team did their calculations in the English calculations in the English standard and the other standard and the other team did it in the metric team did it in the metric system (OOPS!)system (OOPS!) MARS

This made scientists very upset.

• It cost the space program 125 million It cost the space program 125 million dollars. dollars.

• It cost the scientists their time.It cost the scientists their time.• This is why it’s important to have and This is why it’s important to have and useuse a a

universal standard of measurement.universal standard of measurement.

Thousand

Hundred

Ten

One

Tenth

Hundredth

Thousandt

h

km

kL

kg(kilo)

1000

hm

hL

hg(hecto)

100

dkm

dkL

dkg(deca)

10

m

L

g(standard

unit)

1

dm

dL

dg(deci)

0.1

cm

cL

cg(centi)

0.01

mm

mL

mg(milli)

0.001

The Metric Chart

Changing Metric Units

• To change from one unit to another in the metric system you simply multiply or divide by a power of 10.

• To change from a larger unit to a smaller unit, you need to multiply (move the decimal to the right).

• To change from smaller units to larger units you divide by a power of ten (move the decimal to the left).

1 km x 1000 = 1000 m1 m x 100 = 100 cm1 cm x 10 = 10mm

1000mm ÷ 10 = 100cm

100cm ÷ 10 = 10dm 10dm ÷ 10 = 1m

Show me you haven’t fallen asleep!

• 100cm = ___ m• 6.9mm = ___cm• 5kg = ___mg• 7.3mL = ___L