Work and Force in Living Things Get your lab notebooks, a pencil, and have a seat. Moore MST Science 6/27/2018

Forces Change Things Write in your notebook about ways that forces cause change. Here are some helpful sentence stems to get you started One way force causes change is ____________. When a force is applied to a _______________, some changes I have noticed are ____________________. Use complete sentences and write for about 2 minutes. Moore MST Science 6/27/2018

Main Ideas Unbalanced forces cause motion. Work = force X distance. Simple machines reduce force and increase distance. Moore MST Science 6/27/2018

Force Force: The cause of motion (what causes objects to move) Two major types of forces Pushes Pulls

Slow Motion Skateboard Crashes While viewing the video, think about what forces are effecting the skateboarders. Moore MST Science 6/27/2018

Measurement of Forces Newtons: SI (metric) unit of force Symbol: N Measured by using a spring scale

Types of Forces Balanced forces – all forces acting on an object are equal There is NO MOTION Unbalanced forces – one or more forces acting on an object are stronger than others There is MOTION Moore MST Science 6/27/2018

Unbalanced forces can = Work When objects or living creatures are moving they can do work. But what is work? In science class work is defined as: a force causing an object to move in the direction of the force applied Effort doesn’t always equal work. I can push on the school building all day long, but little or no work will be done. Moore MST Science 6/27/2018

What is Work? Work can be calculated with the following formula: W = F * d Work equals force X distance Work is measured in a metric unit called joules (J) newtons joules meters Moore MST Science 6/27/2018

What is Work? W = F * d Let’s solve an example problem: If student “A” lifts a box of Christmas lights with 11 newtons of force 3 meters to the rooftop, how much work has he done? A: W = 11 X 3 = 33 joules of work Moore MST Science 6/27/2018

What is Work? W = F * d Let’s solve an example problem: If student “A” pushes a box with 5 newtons of force 8 meters down the hall, and student “B” lifts a box with 12 newtons of force 2 meters to the top of a table, who has done the most work? A: W = 5 X 8 = 40 joules of work B: W = 12 X 2 = 24 joules of work Moore MST Science 6/27/2018

What is Work?- a review Work = Force X Distance Work is the product of a force applied Causes movement in the direction of the force applied (no movement in the direction of the force = no work) If I push against a house no work is accomplished… W = F * d Work is measured in joules; force in Newtons; distance in meters Moore MST Science 6/27/2018

The Great Book Drag Work in lab-groups of 4 Share data between all 4 Each group of two will turn in their own paper Measure the force required to lift a book .5 meters versus using a ramp to pull a book to the same height. Be sure and follow directions! Ask your lab partner before me! Moore MST Science 6/27/2018

How simple machines make work easier BIG SCIENCE IDEA: Simple machines such as ramps, wheels, levers, etc. change the direction of our input force or allow us to use less force because they increase the distance Remember: Work = force X distance Moore MST Science 6/27/2018

Work and No Work Contrast the situations of work and no work using an illustrated comic strip. Identify the forces at work in those situations. Describe the force and work being done in the illustrations (if there is work being done). Moore MST Science 6/27/2018

Main Ideas Unbalanced forces cause motion. These forces are observable in the everyday life of organisms. In plants the emergence of seedlings relies on unbalanced forces to allow the seedling to push its way to through the soil. Force in the form of pressure allows green-stemmed plants to stand upright. This turgor pressure also keeps vegetables crisp. Plants also respond to forces in the way they grow. Geotropism is the growth of a plant in response to gravity. In animals, the contracting of muscles allows for movement of the organism. For example- the muscles of the heart create forces which cause the flow of blood through the circulatory system. When a force is applied to an object and the object moves, work is done. In the physical sense, work is equal to the force multiplied by the distance. Moore MST Science 6/27/2018

Plant Tropisms Tropisms occur when plants respond to external stimuli. Tropisms are movements caused by a change in a plant’s growth pattern. Tropisms can be negative or positive. If the plant moves toward the stimulus, the tropism is defined as positive. If the plant moves away from the stimulus, the tropism is considered negative. Moore MST Science 6/27/2018

Plant Tropisms Moore MST Science 6/27/2018

Plant Tropisms Moore MST Science 6/27/2018

Plant Tropisms Moore MST Science 6/27/2018

Plant Tropisms Moore MST Science 6/27/2018

Plant Tropisms Let’s see some- “Plants in Motion” http://plantsinmotion.bio.indiana.edu/plantmotion/starthere.html Moore MST Science 6/27/2018

Thigmotrophism Phototropism Thigmotrophism What type of tropism is shown in these pictures? Phototropism Geotropism Thigmotrophism Phototropism Geotropism Thigmotrophism Moore MST Science 6/27/2018

Virtual Corn Geotropism Lab Does gravity affect the emergence of a corn seedling? We will record our hypothesis and information in our lab-books: work with lab partner Moore MST Science 6/27/2018

Virtual Corn Geotropism Lab Problem/Question: Does gravity affect the emergence of a corn seedling? Research: Discuss with lab partner Hypothesis: If -------, then -------… Experiment: Draw the initial placement and appearance of the 4 corn seeds; explain procedure, etc. Data & Conclusion: ??? Corn seed Petri Dish Moore MST Science 6/27/2018

Virtual Corn Geotropism Lab Day 1: Petri Dish Corn seed Moore MST Science 6/27/2018

Virtual Corn Geotropism Lab shoot/stem Day 4: root Moore MST Science 6/27/2018

Virtual Corn Geotropism Lab shoot/stem Day 4: root Moore MST Science 6/27/2018

Virtual Corn Geotropism Lab Problem/Question: Does gravity affect the emergence of a corn seedling? Research: Discuss with lab partner Hypothesis: If -------, then -------… Experiment: Draw the initial placement and appearance of the 4 corn seeds; explain procedure, etc. Data & Conclusion: ??? Corn seed Petri Dish Moore MST Science 6/27/2018

Today’s Pre-AP Assessment Work with your lab partner Design your own science experiment to test a question about one of the types of tropisms that we have studied: Geotropism Hydrotropism Thigmotropism Phototropism Remember the steps of the scientific method: People really hate eating dirty carrots. Problem, Research, Hypothesis, Experiment Moore MST Science 6/27/2018

Main Ideas Unbalanced forces cause motion. These forces are observable in the everyday life of organisms. In plants the emergence of seedlings relies on unbalanced forces to allow the seedling to push its way to through the soil. Force in the form of pressure allows green-stemmed plants to stand upright. This turgor pressure also keeps vegetables crisp. Plants also respond to forces in the way they grow. Geotropism is the growth of a plant in response to gravity. In animals, the contracting of muscles allows for movement of the organism. For example- the muscles of the heart create forces which cause the flow of blood through the circulatory system. Moore MST Science 6/27/2018