Daily Head Scratcher… 1. Do objects with large masses always have large weights? 2. Explain the relationship between mass and inertia.
Daily Head Scratcher… 9/14/2011 Using your periodic table of the elements, create a model (with protons, neutrons and electrons) for the atom with the symbol P. Make a Bohr model and a Lewis dot model for the same atom.
Daily Head Scratcher… 9/14/2011 Use the following data table to create a graph. How much salt can be added to water that is 35 degrees celsius in order for it to reach its saturation point?
Daily Head Scratcher… 9/16/11 1. Mrs. McNiece wanted to see how different types of music affected students' pulse rates. She played different types of music: heavy metal, rap, R&B, alternative, pop, country, and classical music. Identify the dependent variable 2. Justin usually blows his nose using Kleenex tissues. His snot keeps leaking through the tissue. He decided he is going to create an experiment to find out if there is something better. Write out an experimental design. What is his independent variable? Dependent variable?
Daily Head Scratcher…9/19/2011 Mr. Leadbetter believes that mice exposed to radiowaves will become extremely strong. 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 mice exposed to radiowaves were able to push the block away. 7 out of 10 of the other mice were able to do the same. Identify the – • Control group • Independent Variable • Dependent Variable • What should Bart’s conclusion be?
Daily Head Scratcher…9/20/2011 A certain type of tree branch obey’s Hook’s Law. When a 50 kg load is hung from the end of it, the branch sags a distance of 5 cm. What if a load of 75 kg is hung from it? • How far will the branch sag? • If the branch sags 10 cm, what load can we assume is hanging from it? • How is Hook’s law similar to the principals behind liquid pressure? (station III)
Daily Head Scratcher…9/21/11 Write out a detailed procedure for brushing teeth.
Daily Head Scratcher…9/23/11 Make the Lewis model for Cl. Make the lewis model for Hydrogen. If the above elements combined, what type of bond would they have?
Daily Head Scratcher… 9/26/11 A group of college students were given a short course in speed-reading. The instructor was curious if a monetary incentive would influence performance on a reading test taken at the end of the course. Half the students were offered $5 for obtaining a certain level of performance on the test, the other half were not offered money. 1. Independent variable: 2. Dependent variable:
Daily Head Scratcher…9/28/11 • Flower Power SpongeBob loves to garden and wants to grow lots of pink flowers for his pal Sandy. He bought a special Flower Power fertilizer to see if will help plants produce more flowers. He plants two plants of the same size in separate containers with the same amount of potting soil. He places one plant in a sunny window and waters it every day with fertilized water. He places the other plant on a shelf in a closet and waters it with plain water every other day. What did SpongeBob do wrong in this experiment? Explain. What should SpongeBob do to test the effectiveness of Flower Power fertilizer?
Daily Head Scratcher…9/28/11 1. Use the graph to describe Carmen’s trip. You can start the description like this: “In the first half hour, Carmen rode the bike for 6 miles. In the second half hour, she increased her speed because…” Think and Discuss 2. Explain how the graph shows how fast Carmen was riding. 3. Determine during which half hour Carmen was riding fastest.
Daily Head scratcher… 12/5/11INFO: A solubility curve is a graph that represents how much SOLUTE is SOLUBLE in a SOLVENT at a given temperature. Every substance has it’s own unique solubility curve. Look at the graph and fill in the blanks… The solubility of the solid chemicals _____________ as the temperature of the water is _____________.
Daily Head Scratcher 12/6/11 Name the IV and the DV for each of the questions. • How does water purity affect surface tension? • When is the best time to plant soy beans? • Which material is the best insulator?
Daily Head Scratcher 12/7/11 Answer the following questions about the element Aluminum: Al • What is it’s atomic #? • What is it’s atomic mass? • How many electrons does it have? • How many neutrons does it have? • How many protons does it have? • Draw it’s Lewis dot diagram.
Daily Head Scratcher 12/8/11 • What was the independent variable in this study? Dependent variable? • Construct a three or more sentence paragraph summarizing the findings in “Effect of added Nitrogen on Plant Height”.
Daily Head Scratcher 12/9/11 • How do different foundations stand up to earthquakes? 2. What sugars do yeast use?
Daily Head Scratcher 12/9/11 • Create a hypothesis to go with each experimental question below. (Remember: A hypothesis is supposed to address causes that lead to effects.) • How do different foundations stand up to earthquakes? 2. What sugars do yeast use?
Answer: The basic form of a hypothesis is usually similar to one of the following: 1) Dependent variable will happen BECAUSE of the independent variable. This form is best used for questions phrased as "What causes _______?" OR 2) AS independent variable is applied THEN the dependent variable will happen or be affected. OR 3) IF independent variable applied AND experiment done, THEN the dependent variable will happen. This version gives the independent variable (If...), basic experimental design (and...), and the dependent variable (then...) in one sentence
Daily Head Scratcher 12/12/11 Which of the following questions are testable ones? • What is the effect of octane on gas milage? • How does washing affect the flame-retardant properties of sleepwear? • What happens when water expands as it freezes? • How do various aquatic plants affect the pH of pond water? • How much force is needed to keep water from expanding as it freezes? 6. How do Rockets work?
Daily Head Scratcher 12/14/11 • Testable questions are those that can be answered through hands-on investigation by the student. The key difference between a general interest science question and a testable question is that testable questions are always about changing one thing to see what the effect is on another thing. • 1,2,4&5. • Citation: Discovery Education, “Science fair Central” http://school.discoveryeducation.com/sciencefaircentral/Getting-Started/Investigation.htm
Daily Head Scratcher 12/14/11 The burning of a candle is a chemical change. What feature of the reaction makes it chemical in nature? • The candle changes in size. • The substance of the candle’s wick changes. • The temperature of the candle changes. • The change requires large amounts of energy.
Daily Head Scratcher 12/14/11 Answer: B
Daily Head Scratcher 12/15/11 Where do physical and chemical changes occur in nature? • They occur only within living organisms. • They occur only within non-living objects. • They occur only outside of, but closely associated with living organisms. • They occur outside of and within both living and non-living objects.
Daily Head Scratcher 1/3/12 If an object at rest is to be set into motion, which of the following is NOT necessarily required? • A force acting on the object. • Overcoming the object’s inertia • Physical contact with another object • A direction of movement
ANSWER: C. Many forces act and create motion without physical contact, so physical contact is not necessarily required.
Daily Head Scratcher 1/4/12 Identify the independent and dependent variable for the following question: How fast does a candle burn?
Answer: Independent : (What I change) Time measured in minutes. Dependent: Height of the candle measured in cm at multiple intervals of time.
Daily Head Scratcher 1/5/12 Identify the control and the dependent variable in the following question: Does an electric motor turn faster if you increase the voltage?
ANSWER: Dependent: Speed of rotation measured in Rotations per minute (RPMs) Control: Same motor for each test. The motor should be doing the same work for each test.
Daily Head Scratcher 1/6/12 Astronomers can predict the positions of each planet in our solar system at any point in the future. Which of the following things are used to predict the orbits of the planets? • Wind patterns. • The sun’s energy • Computer modelling • Mathematical models
ANSWER: D. Scientists can use mathematical models to predict the movements and positions of objects orbiting in our solar system.
Daily Head Scratcher 1/9/12 • Which of the following is NOT an ion? • H +1 • Br- • O2 • Mg +2 • NO 3- • Which of the following elements will most likely form an ion with a +2 charge? • Na • Mg • Ne • Si • Cl
Answer: 1. C. 2. Mg
Daily Head Scratcher 1/11/12 If you take money away from your bank account and the bank will show a negative credit. Take an electron away from an atom, however, and the atom shows up positive. Explain.
Answer: A neutral atom contains identically charged but oppositely signed protons and electrons. Removing one of the negative electrons results in an excess of positively charged protons.
Daily Head Scratcher 1/12/11 1. Given the following generic chemical reaction, which is the product and which is the reactant? X Y 2. For the following balanced equation, which has the highest coefficient? 4 H2 + 2 C 2 CH4
Daily Head scratcher 1/17/12 • Since atoms are mostly empty space, why don’t objects pass through one another? • The electrons on the atoms repel other electrons on other atoms when they get close. • The nucleus of one atom repels the nucleus of another atom when it gets close. • The nucleus of one atom attracts the nucleus of a neighboring atom to form a barrier. • The electrons of one attracts the nucleus of a neighboring atom to form a barrier.
Daily Head Scratcher 1/18/2012 Three high school students wanted to investigate how far they could drive if the gas tanks of the cars were full of gasoline. The students went to the same gas station to fill the tanks of the cars. The drove the cars until the gas tanks were nearly empty. The table shows all the information the students collected during their investigation. Describe three specific changes the students could make to improve their experiment.
Answer: Should contain: • Drive the cars at the same speed. • Drive the cars on the same road. • Put the same amount of gas in each car. • Monitor the amount of gas more closely. • Conduct more trials of the experiment to obtain more reliable data. • Have the same person drive each car.
Daily Head Scratcher 1/19/12 Three groups of students decided to design experiments to learn more about the process of evaporation. One group of students used the four different containers shown below. The students poured 100 milliliters of water at 20 degrees C into each container. The containers were placed side by side on a table near the window for 24 hours. The next day the students used a graduated cylinder to measure the amount of water left in each container. Write one question the students were probably trying to answer in their investigation.
answer Elements of correct answer: • Does the container size have any effect on evaporation rate? • Does container shape have any effect on evaporation rate? • In what type/kind of container will water evaporate fastest? • Any question that relates containers’ shape or size to evaporation rate.
Daily Head Scratcher 1/20/12 Another group of students decided to see if different liquids evaporate at the same rate at room temperature. The students decided to test three liquids: freshwater, saltwater, and rubbing alcohol. The students poured 50 mL of each liquid into a separate beaker. All the beakers were placed next to one another on a shelf. After two days, the students used a graduated cylinder to measure the amount of liquid remaining in each beaker. The table below shows the results. Before the experiment, the students had the hypothesis that saltwater would evaporate faster than other liquids. Do the results of the experiment support the hypothesis? Explain your answer.
Answer: Elements of correct answer: • No, the table shows that less of the freshwater and rubbing alcohol were left. • No, more liquid evaporated from the beakers containing freshwater and rubbing alcohol. • No, the amount of freshwater and rubbing alcohol left in the beakers was less than the saltwater. • No, 11.4 mL of saltwater evaporated which is less than the evaporated freshwater (14.7 mL) and rubbing alcohol (27.3 mL). • Any explanation that data does not support the hypothesis since more saltwater was left or less saltwater evaporated than the other two liquids.
Daily Head Scratcher 1/20/12 Use four steps to describe a process to separate a mixture of iron filings, wood shavings, and salt.
Answer: Use a magnet to separate iron filings Add water to dissolve the salt and filter off the wood shavings Evaporate the water to obtain the salt.
Daily Head Scratcher 1/23/12 The graph below shows the distance a student walks down a hall over time. Use the information shown on the graph. 1. During which time interval was the student moving the fastest? A, B, C, D 2. What was the average speed of the student from 0 to 5 seconds? _____________________
Answers: • D • 2 m/s