Experimental Variables & Video Practice

Experimental Variables & Video Practice

1. Day 2 - Experiments

2. The Plan: Discuss experimental design and variables

3. What is an ​experiment? Experiment - a test under controlled ​conditions that is made to show a certain principle or to ​test a hypothesis.

4. To make sure that an experiment yields ​useful results, it must be performed under ​controlled conditions . We refer to these controls as experimental variables . Variable - any factor that can be changed or controlled in a situation

5. In a scientific experiment, there are 3 ​different kinds of variables that we need ​to consider: 1. The Manipulated Variable (MV)  - the variable that is deliberately  changed 2. The Responding Variable (RV)  - the variable we actively measure; the variable that responds to changes in the ​manipulated variable. 3. The Controlled Variables (CV's)  - the variables that must remain ​constant throughout the experiment.

6. Lab Write Up

7. Let's Practice Identifying Variables in a few different situations

8. 1) Begin with a testable question that defines the manipulated and responding variables. EXPERIMENTAL PROCEDURE 2) Write a prediction or hypothesis. 3) Make careful observations and record the results. Analyze those results (create a table, graph, or diagram if necessary). 4) Explain why you saw these results. 5) Ask a new testable question that would deepen or confirm your understanding of what you learned in the experiment.

9. A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable. This increases the reliability of the results, often through a comparison between control measurements and the other measurements. CONTROL FAIR TEST It is important for an experiment to be a fair test. You conduct a fair test by making sure that you change one factor at a time while keeping all other conditions the same.

10. What makes a test fair? The importance of a Fair test: how can you possibly know the correct result if the test is not fair?

11. FAIR TEST For example, let's imagine that we want to measure which is the fastest toy car to coast down a sloping ramp: how could we make this a fair test?

12. Question: Which is faster, sound or light? Problem statement : If I shine a flash light across a football field (at night) at the same time as I blast an air horn, which will cross the field fastest: the sound or the light? Hypothesis: I think that the sound will cross the field the fastest because the darkness will slow the light down. Observations/Results: The air horn sound arrived at the other side of the football field about 0.5 seconds after the light could be seen. Interpretation: The light crossed the football field first because light is faster than sound. Next Question: If I do the same experiment underwater, which will be faster: light or sound? Can you identify: MV, RV, and fair test?

13. A sentence that identifies the possible relationship between the manipulated and responding variable. PROBLEM STATEMENT How does the MV affect the RV ?

14. A testable claim, often based on evidence and or reasoning. HYPOTHESIS Example: "Have you noticed that Howard can take any topic and use it to remind you that he went to space?"

15. Detailed examination of something. ANALYSIS Explaining the meaning of something. INTERPRETATION (INDUCTION)

16. The Plan: We will practice identifying variables, write problem statements, practice hypothesizing.

17. A. Float or sink soda can Choose your own examples B. Elephants afraid of mice C. Bull in a China Shop D. Marshmallow test E. Coca Cola & Milk F. Burning money G. Elephants and mice I. Does Methane and CO2 actually make the air hotter? H. Crowd wave time J. Weaving in traffic K. Swimming in syrup L. Dropping potatoes M. Big bang theory N. Fizzy pop cans O. Plant Growth P. Curving bullet Q. Gummy bears/rocket fuel