Experimental Investigations Adapted from Stemscopes Malnory/Pietsch 7 th grade science Anna Middle School

Teacher Notes.  Example student responses:  1. My Question of Inquiry: Example responses: What prevents the signal from the transmitter  from reaching the receiver? What materials block radio waves?  2. The Hypothesis: Responses depend on the question, examples responses: If materials that  contain metal come between a transmitter and receiver, the remote controlled car will not move.  Look to see that your students understand that they will vary type of material used to see what  happens with the responding variable.  3. What is the independent variable (also known as the manipulated variable)? The independent  variable is the type of material used to wrap around a transmitter (remote control).  4. What is the dependent variable (also known as the responding variable)? The responding  variable depends on the well-defined question that leads to the hypothesis, example response:  the movement of the car.  5. Is there a control group or control variable for this investigation? Explain. Yes. The one trial as  the control with not have anything wrapped around the transmitter (remote control).  6. What materials, equipment, and technology will I need for this investigation? Example  response: Remote control and remote controlled device, meter stick, batteries, various  materials such as foil, paper, plastic, glass, etc.  7. What safety precautions must I take in this investigation? Example response: Normal safely  precautions for investigations are used, special precautions are not necessary.

Experimental Investigations  Experimental investigations involve designing a “fair test” similar to a comparative investigations,  but a control is identified. The variables are measured in an effort to gather evidence to support or  not support a causal relationship. This is often called a “controlled experiment”.

Experimental Investigation  When planning an experimental investigation, the first step is to ask a well defined question.  You might ask, “What prevents a remote controlled device from responding?”  Then you need to ask: “How are radio waves received and transmitted?” or  “Do some materials block radio waves?”

Experimental Investigations  Just as in a comparative investigation, we compare the same thing under different circumstances. We make sure that we only change one variable at a time and keep all other conditions the same.  Only the independent (manipulated) variable is changed to observe the response of the  Dependent (responding) variable. Additionally, a control sample is included

Experimental Investigation  While riding your bike, you notice a toy radio controlled car racing by. You stop and look around for  the source and see your neighbor at the end of the block holding a remote control. The toy car  continues on, makes a turn and then stops. Your neighbor walks up to you and says that every  time the car makes that turn, it stops because it seems to loose connection with the controller.  That makes you start wondering about what could be preventing the radio signal from the  transmitting controller from reaching the receiver on the car.

Experimental pg 3 handout  1. My Question of Inquiry:  ______________________________________________________________________ ______  2. The Hypothesis:  ______________________________________________________________________ ______  3. What is the independent variable (also known as the manipulated variable)?  ______________________________________________________________________ ______  4. What is the dependent variable (also known as the responding variable)?  _______________________________________________________________

Experimental pg. 3 cont.  5. Is there a control group or control variable for this investigation? Explain.  6. What materials,  equipment, and  technology will I  need for this  investigation?

Experimental pg. 3 cont.  7. What safety precautions must I take in this investigation?  _________________________________________________ ___________________________  _________________________________________________ ___________________  8. I will implement this investigation using the following procedures.  Record your procedure on the back of this worksheet or in your lab journal if needed.  Youtube video: Electromagnetic wave shielding (radio)