Work, Force and Motion Students complete a pre review in their Textbooks.

What are the ways forces cause change? One way force causes change is ____. When a force is applied to a ____, some changes I have noticed are _____. So, what do you know about Force? In pairs, write the answer to these questions on the white board: Each pair will explain their answers.

TEKS 7A: The student will contrast situations where work is done with different amounts of force to situations where no work is done such as moving a box with a ramp and without a ramp, or standing still. TEKS 7C: The student will demonstrate and illustrate forces that affect motion in everyday life such as emergence of seedlings, turgor pressure, and geotropism.

Vocabulary 1) Work – the application of a force to an object and the object’s movement in the direction the force is applied. 2) Turgor pressure – pressure exerted by water inside the cell on the cell wall. 3) Geotropism – growth that happens in living organisms in response to gravity, such as the downward growth of plant roots.

Work = Force X Distance W=Fd (see reference material in back of your notebook) In order for work to take place, the object must move when the force is applied. Force is measured in newtons (N), distance is measured in meters (m) (convert centimeters to meters), and work is a calculated unit joules (J). W(Joules) = F(Newtons) x d(meters) If I kicked a soccer ball with 4 N of force, and it went 10 meters, then I did 40 J of work. Equation: 4N x 10 m = 40 J

Setting up your Investigation proving the Forces on Seedlings and Plants Watch as the teacher demonstrates the three experiments. Take notes in your notebook and read along with the handout. Then, the class will be divided into three groups and each will set up one of the experiments. These three experiments will be observed for the next 8 days and you will prepare one page to write in your Science Notebook what you observe each day. Students construct a data table in which to diagram the three set-ups, make predictions about the results, and record the results of the investigations.

Date It!! 1)Problem: What forces affect the motion of plants? 2)Hypothesis: If a force is being applied, then some changes I will notice are…(you write your prediction, now)……………….. Geotropism 3) Materials 4) Procedure 5) Drawing/Data Observation: 9/29/14 I saw ……… 9/30/14 I saw ……… 6) Results: Emergence of Seedlings 3) Materials 4) Procedure 5) Drawing/Data Observation: 9/29/14 I saw ……. 9/30/14 I saw ……. 6) Results: Turgor Pressure 3) Materials 4) Procedure 5) Drawing/Data Observation: 9/29/14 I saw ……. 9/30/14 I saw ……. 6) Results: cup plaster seeds Salt water water 7) Conclusion: The forces that affect the motion of plants are --(your answer)- And my hypothesis was -----(your answer)----because-----(your answer)-- 8) Application: I see this information important because ----(your answer)--

Scientists have a very specific definition of the term “work”. It involves both force and motion.

See webpage Don’t use the wrong side of the meter stick!

The purpose of this investigation will be to illustrate situations of work vs. situations of no work. Instruct students to set up a page or pages in their science notebooks on which to record observations of various situations involving force and motion. Explain to students that for each station, students will diagram the situation, identifying the forces involved, and showing the direction of motion. They will need room for each station in their notebooks and should leave room after each station for additional notes. video

Explain to students that they will be placed into one of six groups and will rotate through the six stations, following the directions on the station cards and recording their observations. Leave room for notes. In your Notebook write: Date It! Station 1: Meter Stick, book (draw, label forces) Station 2: meter stick, book, string (draw, label forces) Station 3: meter stick, book Station 4: meter stick, book, timer Station 5: meter stick, wall Station 6: meter stick, book, string videos

Explain (or remind) students there is a tool used to measure force. Introduce students to a spring scale. Allow students to work back through the six stations again, but this time they will measure the amount of force applied in each situation. You will need to attach the spring scale to the object with string. Pull. And while pulling, record the Force on the scale; N (newton). Video:

F x d = W Then, Small group activity: Each person must check their work with 3 other people. Then, Large group activity: discussion on results. END

Students may think that applying force equals work, rather than work occurs when a force is used to move an object through a distance.