Science Starter8.22-23.2013

Bart believes that mice exposed to radiowaves will become extra strong (maybe he's been reading too much Radioactive Man). He decides to perform this experiment by placing 10 mice near a radio for 5 hours. He compared these 10 mice to another 10 mice that had not been exposed. His test consisted of a heavy block of wood that blocked the mouse food. He found that 8 out of 10 of the radiowaved mice were able to push the block away. 7 out of 10 of the other mice were able to do the same.

1. What were the results (observations) of Bart’s experiment?

2. What kind of observations are these?

3. What should Bart's conclusion (inference) be?

4. Identify the independent and dependent variable using your cheat sheet.

Control Variables and Control Groups

Is there a difference?

Let’s say a scientist develops a special vitamin, Study No More, that claims to help students remember everything the teacher says in class which, in turn, will keep them from having to study. (Woooohoooo!)

IV: The usage of STUDY NO MORE

DV: The ability of a student to remember everything

Testable Question: How does changing the usage of STUDY NO MORE affect the ability of a student to remember everything?

Writing Our Hypothesis…

• Hypothesis statements are what you think the outcome will be (infer or predict) in the experiment based on your observations.

• They are usually written in the following format: “If IV, then DV.

Hypothesis: If a student takes STUDY NO MORE, then he/she will remember everything.

How would we know if the scientist’s claim is true? Should all students in the experiment use STUDY NO MORE? What needs to happen?

One group of students do not need to take STUDY NO MORE. They are called the control group, or experimental control.

A control group, or experimental control is the “normal” group that IS NOT exposed to the independent variable. This group is used to compare the results to observe if the independent variable caused a change.

The experimental group is the group who IS exposed to the independent variable. They are the “guinea pigs” of the group.

Does STUDY NO MORE really work?

• 100 students took part in the experiment to test STUDY NO MORE vitamins. Here are the results:• Of the 50 students who took STUDY NO MORE, 38 could not

remember everything while 12 could remember most.• Of the 50 students who did not take STUDY NO MORE, 32 could

not remember everything while 17 could remember most. One student remembered everything the teacher said in class.

• What conclusion can we make about STUDY NO MORE? • STUDY NO MORE does not really make you remember

everything. My hypothesis was incorrect because I thought STUDY NO MORE would make students remember everything.

Got to practice to be perfect!

Krusty was told that a certain itching powder was the newest best thing on the market, it even claims to cause 50% longer lasting itches. Interested in this product, he buys the itching powder and compares it to his usual product. One test subject (A) is sprinkled with the original itching powder, and another test subject (B) was sprinkled with the Experimental itching powder. Subject A reported having itches for 30 minutes. Subject B reported to have itches for 45 minutes

• Independent Variable • Type of itching powder

(Experimental powder)

• Dependent Variable• Length of time of itchiness

• Control Group • Group A

• Explain whether the data supports the advertisements claims about its product.

Just a little more practice!

Patrick and SpongeBob love to blow bubbles! Patrick found some Super Bubble Soap at Sail-Mart. The ads claim that Super Bubble Soap will produce bubbles that are twice as big as bubbles made with regular bubble soap. Patrick and SpongeBob made up two samples of bubble solution. One sample was made with 5 oz. of Super Bubble Soap and 5 oz. of water, while the other was made with the same amount of water and 5 oz. of regular bubble soap. Patrick and SpongeBob used their favorite bubble wands to blow 10 different bubbles and did their best to measure the diameter of each one. The results are shown in the chart on the next slide:

• What did the Super Bubble ad claim?

• What is the independent variable?

• Type of bubble solution (Super Bubble Soap)

• What is the dependent variable?

• Size or diameter of bubble

• What is the experimental control?

• Regular soap bubble

• What can you conclude from the data?

Quiz Bonus• Complete corrections on notebook paper.

• List the problem number.

• Use your notes (not someone else’s quiz) to help you determine the correct answer.

• Using COMPLETE sentences, explain why you missed the question and then write the correct answer. Underline your correct answer in your explanation.• Example: I missed the control variables because I was

not specific about the bread. My correct answer for the control variable is the type of bread.

• Staple your notebook paper to the BACK of your original quiz and turn it in the bin.