Mystery Footprints Case #2

One Saturday morning Nina saw the three musketeers in the mall. Jenny, Brittany, and Mitzi called themselves by that name because they always were together. "I've been shopping for sandals," Jenny told Nina. "But I have such a wide foot nothing seems to fit. We've been looking everywhere." "And it's been slow going," Mitzi added. "On account of Brittany's-" "I know," Nina said looking at Brittany, "I heard you sprained your ankle in gym yesterday. Does it still hurt a lot?" "It's okay as long as I move really slowly," Brittany told her. "We're going to get ice cream at the Just Desserts Shop now. Want to join us?" "Better not,” Nina said, “ Max is meeting me at home. See you later." Source:

Nina was taking a short cut through Harborville's city park when she saw Mr. Hansen kneeling beside a new sidewalk. The city maintenance man frowned as she drew closer. "Somebody jumped right in the middle here while the cement was still wet," he said, pointing at two narrow footprints embedded in the concrete. "Now I'll have to rip out this section and re-do it. Sure can't leave the sidewalk looking like this!" "Any idea of who did it?" Nina asked. "A kid over there on the slide said that girls named Brittany, Mitzi, and Jenny were the only ones near here. But he doesn't know which one ruined my sidewalk." "I know who did it," Nina declared. How did Nina figure it out?

The footprints were narrow. Jenny had wide feet. Because of her sprained ankle, Brittany would not have jumped. Since Mitzi was the only one left, she had to be the guilty one.

Key Ideas How Can I think like a scientist? How do scientists measure things? Why it matters? Thinking logically, or like a scientist, can help you solve daily problems. Which method of training is helping me improve my running times? 1.2 The Way Science Works

Activity Investigate the impact that adding various amounts of fertilizer has on plant growth. Think about what you would need to do to conduct this experiment. 1.2 The Way Science Works Disclaimer****** - Thinking has been shown to challenge the capacity of your brain, I, Mr. Shull am not responsible for any resulting injuries of this activity, SO DON’T HURT YOURSELF!

How can I think and act like scientist? Identifying problems, planning experiments, recording observations, and correctly reporting data are some of the most important science skills. Scientists approach a problem by thinking logically. 1.2 The Way Science Works

The Scientific Method a series of steps followed to solve problems including collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions The scientific method is a description to follow, not an exact path that has to be followed. 1.2 The Way Science Works They are all intertwined!

Observe Observe/watch anything in nature Formulate a question What do you want to know? Research and collect data What is already known about your question Form a hypothesis Propose an answer to your question based on observations, research, and data Test the Hypothesis Observe Draw Conclusions Did your results support your hypothesis? If not modify the hypothesis based on observations 1.2 The Way Science Works Observations give additional data for a new hypothesis

hypothesis: a possible explanation or answer that can be tested Scientists test a hypothesis by doing a controlled experiment. controlled experiment: an experiment in which the variables that could affect the experiment are kept constant (controlled) except for the one that you want to measure variable: a factor that changes in an experiment in order to test a hypothesis Only Change 1 Variable!!!!!!!!!!!!!!!!!!!!!!!! 1.2 The Way Science Works

Experiments test ideas. No experiment is a failure! The results of every experiment can be used to revise the hypothesis or plan tests of a different variable Peer Reviewed Research: Research that has been reviewed by other scientists. 1.2 The Way Science Works Other scientists perform the experiments themselves to confirm your results.

These experiments are always being performed as new information becomes available to us Earth’s Systems Space Biology Hibb’s Boson particle Forensics (DNA cases) Which leads us to… The Way Science Works

Science and technology are heavily dependent on one another. What special tools can you think of that scientists use? Ex – Telescopes Particle Accelerators Satellites Many, many, many, many, many, many, many, many more. Microscope Types? New discoveries in technology can lead to new discoveries in science. 1.2 The Way Science Works House dust mite

Well, how do scientists measure things? Feet, inches, yards, gallons, cups, quartz? Do you realize how hard those are to convert? Scientists use standard units of measure that together form the International System of Units, or SI. Units of measure are easily converted and are the same throughout the world. 1.2 The Way Science Works

SI units are used for consistency. SI has seven base units. Derived Units: Combinations of base units. Kilo-gram Centi-meter Milli-second 1.2 The Way Science Works

SI (Le Système Internationale d’Unités) 1.2 The Way Science Works

SI prefixes are for very large and very small measurements. The prefixes are multiples of ten. SI Prefixes for small measurements Centi-meter =.01 meters 1.2 The Way Science Works

SI prefixes for large measurements Kilo-gram = 1,000 grams Kilo-meter = 1,000 meters Mega-watt = 1,000 watts 1.2 The Way Science Works

The metric system is based on a base unit that corresponds to a certain kind of measurement Length = meter Volume = liter Weight (Mass) = gram Prefixes plus base units make up the metric system Example: Centi + meter = Centimeter Kilo + liter = Kiloliter

The three prefixes that we will use the most are: kilo centi milli kilo hectodeca Base Units meter gram liter deci centimilli

So if you needed to measure length you would choose meter as your base unit Length of a tree branch 1.5 meters Length of a room 5 meters Length of a ball of twine stretched out 25 meters

But what if you need to measure a longer distance, like from your house to school? Let’s say you live approximately 10 miles from school 10 miles = meters is a big number, but what if you could add a prefix onto the base unit to make it easier to manage: meters = kilometers (or 16.1 if rounded to 1 decimal place)

These prefixes are based on powers of 10. What does this mean? From each prefix every “step” is either: 10 times larger or 10 times smaller For example Centimeters are 10 times larger than millimeters 1 centimeter = 10 millimeters kilo hectodeca Base Units meter gram liter deci centimilli

Centimeters are 10 times larger than millimeters so it takes more millimeters for the same length 1 centimeter = 10 millimeters Example not to scale 1 mm 1 cm

For each “step” to right, you are multiplying by 10 For example, let’s go from a base unit to centi 1 liter = 10 deciliters = 100 centiliters 2 grams = 20 decigrams = 200 centigrams kilo hectodeca meter liter gram deci centimilli ( 1 x 10 = 10) = (10 x 10 = 100) (2 x 10 = 20) = (20 x 10 = 200)

An easy way to move within the metric system is by moving the decimal point one place for each “step” desired Example: change meters to centimeters 1 meter = 10 decimeters = 100 centimeters or 1.00 meter = 10.0 decimeters = 100. centimeters kilo hectodeca meter liter gram deci centimilli

Now let’s try our previous example from meters to kilometers: meters = decameters = hectometers = kilometers So for every “step” from the base unit to kilo, we moved the decimal 1 place to the left (the same direction as in the diagram below) kilo hectodeca meter liter gram deci centimilli

If you move to the left in the diagram, move the decimal to the left If you move to the right in the diagram, move the decimal to the right kilo hectodeca meter liter gram deci centimilli

Now let’s start from centimeters and convert to kilometers centimeters = 4 kilometers centimeters = kilometers kilo hectodeca meter liter gram deci centimilli

Now let’s start from meters and convert to kilometers 4000 meters = 4 kilometers kilo hectodeca meter liter gram deci centimilli kilo hectodeca meter liter gram deci centimilli Now let’s start from centimeters and convert to meters 4000 centimeters = 40 meters

Now let’s start from meters and convert to centimeters 5 meters = 500 centimeters kilo hectodeca meter liter gram deci centimilli kilo hectodeca meter liter gram deci centimilli Now let’s start from kilometers and convert to meters.3 kilometers = 300 meters

Now let’s start from kilometers and convert to millimeters 4 kilometers = millimeters or 4 kilometers = 40 hectometers = 400 decameters = 4000 meters = decimeters = centimeters = millimeters kilo hectodeca meter liter gram deci centimilli

Summary Base units in the metric system are meter, liter, gram Metric system is based on powers of 10 For conversions within the metric system, each “step” is 1 decimal place to the right or left Using the diagram below, converting to the right, moves the decimal to the right and vice versa kilo hectodeca meter liter gram deci centimilli

Units of measure that tell you a number, or quantity? Quantitative! Measurements quantify your observations. length: a measure of the straight-line distance between two points mass: a measure of the amount of matter in an object volume: a measure of the size of a body or region in three- dimensional space weight: a measure of the gravitational force exerted on an object 1.2 The Way Science Works

Observation Something you can see Inference Coming to a conclusion based on your observations 1.2 The Way Science Works

What Inferences can you make from your observations of this picture?

Review Questions! 1.2 The Way Science Works